17th Project Integration Meeting Handout PIM... · with you to the PIM! ! ~ LI n . . ~ . . G . . n...

5101-168

Department of Energy

Low-Cost Solar Array Project

17th Project Integration Meeting

Handout

Pasadena Center February 4-5, 1981

Jet Propulsion Laboratory

California Institute of Technology

Pasadena, California

3-8

Prepared by the Jct Propulsion Laboratory, California lnstllutc or T ech nology,

for the Dcpartn1<:nt or Energy through an agreement with the National

Aeronautics and Space Administration.

The J PL Low-Cost So lar Array Project 1, sponsored by the Department or Energy

(DOE) and forms part of the Solar Photovoltaic Conversion Program to initiate a

major effort toward the development of low-cost solar arrays.

This report was prepared as an account of work sponsored by the United States

Government. Neither the United States nor the United States Department of

Energy , nor an y of their em ployees, nor any or their contractors, subcontrac tors.

or their cn1ployccs, makes any warranty. express or implied . or assumes any icgal

liability or responsilJ1lity for the acrnracy, completeness o r usdulncss of any

infor1na11nn, apparatus, product or procc,, disclosed, or reprcwnts that its use would not 111fr111ge privately nwne<.1 righrs.

REMINDER:

Please bring this Handout

with you to the PIM! !

~ LI

n . .

~ . .

G . .

n LI

r1 u

5101-168

Department of Energy

Low-Cost Solar Array Project

17th Project Integration Meeting

Handout

Pasadena Center February 4-5, 1981

Jet Propulsion Laboratory California Institute of Technology


LOW-COST SOLAR ARRAY PROJECT

PROJECT MANAGER W. T. CALLAGHAN

DEPUTY MANAGER R.R. McDONALD

SECY: M.J. PHILLIPS FINANCIAL

STAFF B. S. LENCK, MGR PROCUREMENT

E. CHRISTENSEN P.S. RYKEN C. T. HANSEN QUALITY ASSURANCE

K.J. ANHALT

I I I I TECHNOLOGY PRODUCTION ANALYSIS ANO ENGINEERING OPERATIONS

DEVELOPMENT AREA PROCESS AND EQUIP. INTEGRATION AREA AREA

K.M. KOUWAD, MGR AREA AREA

M. LEIPOLD, DEP.MGR. D .B. BICKLER, MGR P.K. HENRY, MGR R.G. ROSS, MGR L.N. DUMAS, MGR

SILICON - PROCESS AUTOMATION - PROJECT - ARRAY ENGINEERING LARGE SCALE MATERIAL TASK INTEGRATION PRODUCTION - -- NEWLY DEVELOPED

- ARRAY TECHNOLOGY - ADVANCED ARRAY TASK

R. LUTWACK, MGR PROCESSES COSTS

REQUIREMENTS L.D. RUNKLE

LARGE AREA Si - TECHNOLOGY TRANSFER - ECONOMICS/

-ARRAY - FAILURE DEVELOPMENT - SHEETTASK INDUSTRIAUZATION ANALYSIS AN;>

- ASSESSMENT OF - ENVIROhlMENTAL REPORTING

J.K. LIU, MGR EMERGING TECHNOLOGY - ARRAY LIFE CYCLE TESTING R&D ANALYSIS - ENVIR/FIELD

ENCAPSULATION - NEAR-TER¥ co:;T - ENVIRONMENTAL TESTS

TASK REDUCTION ASSESSMENT - - PERFORMANCE

C. COULB!:RT, MGR MEASUREMENTS

ADVANCED -MODULE

PHOTOVOL TAICS INTERFACE AND - TASK CONTROL

R.J. STIRN, MGR

---MIIJ -- - - ·IQ fflk\T@ljt -

~

0 ' .

n 0 n 0 n ~

n ~~

C 0 n '

'

n n ~

a D 0 0 0

CONTENTS

MEETING OBJECTIVES----------------------------------------------- 1

MAP: Meeting Locations------------------------------------------ 2

AGENDAS---------------------------------------------------------- 3

IPEG4 DEMONSTRATION---------------------------------------------- 9

STATUS OF TECHNOLOGY TRANSFER------------------------------------ 11

TECHNICAL SUMMARIES

Project Analysis and Integration--------------------------- 19

Silicon Material------------------------------------------- 21

Large-Area Silicon Sheet----------------------------------- 27

Encapsulation---------------------------------------------- 41

Advanced Photovoltaics ------------------------------------- 49

Production Process and Equipment--------------------------- 51

Engineering------------------------------------------------ 65

Operations------------------------------------------------- 75

LSA PROJECT ACTIVE CONTRACTS------------------------------------- 85

LSA PROJECT PUBLISHED DOCUMENTS---------------------------------- 89

MAPS: Pasadena Area; Pasadena Center-------------------------- Inside Back

Cover

For Your Information

Check-in: Please check in at the registration desk on the lower level of the conference building before the start of the meeting on Wednesday morning.

Telephone Messages: Incoming calls will be received at JPL on (213) 577-9520. Constant coverage of this phone will be provided and messages transmitted.

Badges: We will appreciate your returning your badges at the end of the meeting.

iii

n ~

. .

n . .

~ ~

a ' '

a u .

.

0 .

a ~

.

I

~

n .

~ . .

a ' .

u D

MEETING OBJECTIVES

The Low-Cost Solar Array Project is convening its 17th Project Integration Meeting (PIM). It will convene at the Pasadena Center (Convention Building) on February 4-5, 1981. Registration will begin at 7:30 a.m. on February 4, lower level of the Conference Building. Attendance is by invitation only.

The Project meetings are conducted to enable an exchange of data within the photovoltaic corrmunity, the LSA contractors, LSA personnel, Department of Energy, NASA Headquarters and other governmental agencies. This exchange is required to assess recent progress; to identify, implement, and evaluate the integration of activities; to gain perspective of trends and new developments; and to guide the near- and long-term planning and adjustment of priorities within the Project •

The objective of the 17th PIM is to perform an overview of technology status of the Project .

1

MEETING LOCATIONS

C 314 C 304 C 306

C312 I t;; 11

C 315 -----C 305 0307

CONFERENCE BUILDING PLAZA LEVEL

1111 Iii iii ii

C 101 C 102 C 103 C 104 C 105

cl Ill H lb

IJI D EXHlBIT AREA D I[

~~:nl EXIT

C 124 C 112

LITTLE THEATRE

[_:rJ -1.: FREIGHT DOOR

I UW>ING

DOCK

CONFERENCE BUILDING LOWER LEVEL

2

I -

I I

I I I I . .

'fl 11

I I I I I I I I I • It

I I

,a Li

rnr u

" Li

fi u

n a n n u

n-ll

a 0

AGENDA

TUESDAY: February 31 1981 - Flat Plate Module/Array Safety Design Workshop - Ross - All day

WEDNESDAY: February 4 1 1981

7:30 Registration

8:30 Welcome and PIM Overview

8:35 Announcements

8:55 Sull111ary of Meeting on Role of Government in Photovoltaics

9:05 Silicon Material Activities

Union Carbide Silicon Process Status Hydrogenation of SiCl 4 for Si Processes Significance of the Hydrogenation Results

9:50 Near Term Cost Reduction Results

9: 30-1 O: 30 Coffee Available

10:30 Encapsulation Materials and Design Principles

11 :15 Flat Module/Array Safety Design Surrmary

11:35 Block IV Module Results

12: 20 Lunch

1:30 MEPSOU* - Presentations and Discussion

2:30-3:00 Coffee Available

3:30 Technology Sessions (Parallel)

Sil icon Material Large Area Silicon Sheet Encapsulation Production Process and Equipment Block IV fttldul e Presentations & Discussions

5: 30 Social Hour

*Module F.xperimental Process System Development Unit

THURSDAY: February 51 1981

8:00 Technology Sessions (Parallel)

Silicon Material Large Area Silicon Sheet Encapsulation Production Process and Equipment Engineering/Operations

9:30-11 :00 Coffee available

12: 00 Lunch

1 :15 Parallel Activities

Encapsulation Materials and Processes Forum

Demonstration/Display - IPEG-4 1

SAMICS Cost Account Catalog, Wafer Crack Detector

2:00-3:00 Coffee Available

3:05 International Perspectives on Photovoltai~s

3:20 surrmaries LSA Lead r.enter DOE

5:00 End of Meeting

3

Lower Lobby of Pasadena Center

Callaghan

Maycock/Magid/Forney

Robil 1 ard

Cl 01

Cl 01

fl04 C314 C301 C312 Cl 05

r.104 C314 r.301 C312 Cl05

ClOl

EXHIBIT AREA

l C101

Kol iwad

Uni on Carbide MIT Lutwack

Boyd

r.uddihy

Ross

Dumas

Bickler

Lutwack Liu Coulbert Bi·ckler P.unkl e

Lutwack Liu coulbert Bickler Ross/Dumas

ruddihy

(Various)

Mlavasky

5 min

20 min

10 min

45 min

20 min

45 min

20 min

45 min

70 min

1 hr 40 min

2 hrs 2 hrs 2 hrs 2 hrs 2 hrs

4 hrs 4 hrs 2 hrs 4 hrs 4 hrs

1 hr 30 min

hr 15 min

hr 15 min

20 min

15 min

1 hr 40 min

SILICON MATERIAL

CHAIRMAN: RALPH LUTWACK

WEDNESDAY - 3:30 p.m. - 5:30 p.m. (Room Cl04)

3:30

4:10

4:35

Silicon Particle Formation and Growth

Process Analysis

Silane/Silicon Process

AeroChem Research Labs

Lamar University

Union Carbide Corp.

5:00 Zinc Reduction of Silicon Tetrachloride Battelle - Columbus Labs

THURSDAY - 8:30 a.m. - 11:00 p.m. (Room Cl04)

8:30 Hydrochlorination Process

8:50

9:30

9:50

10:30

Dichlorosilane CVD Process

Coffee

Definition of Purity Requirements

Effects of Impurities on Solar Cell Performance

4

Massachusetts Institute of Tech.nol ogy

Hemlock Semiconductor Corporation

Westinghouse R&D Center

c. T. Sah Associates

I I I I I I ,, I I I I I I I I I I I I

D n a a n n 0 a 0 ,~ iA

0 '

0 .D

u 0

LARGE AREA SILICON SHEET

CHAIRMAN: Jim Liu

WEDNESDAY - 3:30 p.m. - 5:30 p.m. (C314/315)

3:30 Web

3:55 EFG

4:20 soc

4:45 02 Analysis

5:05 Characterization

5:20 Discussion

THURSDAY - 8:00 a.m. - Noon (Room C314/315))

8:00 Advanced Czochralski

8:?.0 Advanced Czochralski

8:40 Semicrystalline Process

9:00 HEM

9:20 FAS:

9:30 r.offee available

9:40 ID

10:00 ID

l 0:20 Characterization

10:40 Cost Analysis

11 :40 ni scussi on

5

Westinghouse

Mobil-Tyco

Honeywel 1

Univ. of Missouri

Materials Research, Inc.

Kayex

Sil tee

SEMIX

Crystal Systems, Inc.

Crystal Systems, Inc.

Silicon Tech. r.orp.

Sil tee

Applied Solar Energy Corporation

PA&I

ENC AP SULA TI ON

CHAIRMAN: CLIFF COULBERT

WEDNESDAY - 3:30 p.m. - 5:30 p.m. (C301/302)

General Topic: Material Degradation and Life Prediction

3:30

4:00

4:20

4:45

Polymer Degradation and Life Modeling

Polymer Degradation Models (EVA)

Polymer Degradation Modeling (acrylic)

Corrosion and Interface Degradation

5: 15 \.lPL Model Verification Testing

THURSDAY - 8:00 a.m. - Noon (Room C301/302)

General Topic: Materials and Process Development

8:00 overview

8:10 Module Design Analysis and Verification

8:45 Low-Cost Materials

9:15 UV Screening Films

9:30 Electrostatic Bonding

9:45 Ion Pl a ting

A. Gupta

Univ. of Toronto

case Western

Science Center

H. Maxwell

Cliff Coulbert

Spectrolab

Springborn

Univ. of Massachusetts

Spire

Il 1 i noi s Tool Works

THUP.SDAY - 1:15 - 3:00 p.m. (Room 101/102) Chainnan: Cuddihy

Forum on Encapsulation Materials and Design Principles

6

I I I I I I I I I I I I I I I I I I I

PRODUCTIP~ PROCESS AND F.QUIPMF.NT

CHAIRMAN: DON BICKLER

WEDNESDAY - 3:00 p.m. - 5:30 p.m. (Room C312)

3:30 Junction Formation

Pulsed Electron Process

Laser

Non-mass Analyzed Ion Implants

THURSDAY - 8:00 a.m. - 12:00 noon (Room C312)

8:00 Metallization

Midfilm Process

Thi ck Fi 1 m Meta 1 Inks

9:00 Assembly

10:00

10:30

Robot Adaptation

Robotics

Coffee

Processing Non-Czochralski Sheet

Opti ca 1 Design

Assessment

7

Spire

Lockheed

In-house/Caltech

Spectrolab

Bernd Ross Assoc.

MBAssociates

In-House

Motorola

Science Applications

Univ. of Pennsylvania

ENGINEERINC/OPERATIONS AREAS ACENDA

CHAIRMEN: ROSS/DUMAS

WEDNESDAY - 3:30 p.m. - 5:30 p.m. (Room Cl05)

3:30

3:40 3:50 4:00 4:10 4:20 4:30 4:40 4:50

5:00

Introduction - Block IV Contracting

Contractor Experience

Applied Solar Energy Corporation ARCO Solar Genera 1 F.1 ec tri c Motorola Corporation

o. Runkle

Photowatt International (Sensor Technology) Solar Power Corporation Solarex Corporation Spire Corporation

Open Discussion: J. c. Arnett (Engineering), R. w. Aster (PA&I), L. D. Runkle (Operations)

THURSDAY - 8:00 a.m. - 11:45 a.m. (Room Cl05)

8:00 Environmental Test Results Griffith

8:15 MIT/LL Field Experience Status Fonnan

8:30 Field Portable IV Curve Tester Cox

8:40 Module Failure Analysis -Shorts to Ground Sollock

9:00 Produce Liability Considerations Weinstein

9:50 Coffee

10:15 Recent Interconnect Fatigue Developments Mon

10:40 Hot-spot Test Method Development Results Gonzalez

11:05 Cell AR coating Reliability Testing r.lemson

11: 25 Minimodule Accelerating Weathering DSET

11 :45 Solar Spectral Measurements DSET

8


n ~ ~

~ .

t !

n n 0.

I

0 n a a a D D a D D D

IPEG4 DEMONSTRATION

Standard methods for estimating manufacturing prices have been established for the LSA Project. Different methods can be used for different purposes. The most detailed and complete method available is to use the SAMIS (Standard Assembly-line Manufacturing Industry Simulation) program. A less detailed and easier to implement method is to use IPEG.

IPE"G stands for Improved Price Estimation Guidelines. The original IPEG was developed before SAMIS was completed, and was replaced by IPEG2 at the 14th LSA PIM. IPEGl and IPEG2 are based on financial and indirect cost parameters which are frozen at the nominal values specified in SAMICS (Solar Array Manufacturing Industry Costing Standards). The result is a straightforward equation which is suitable for manual calculations.

IPEG4 is a computer program which develops IPEG2 type models that are specially calibrated for particular financial and indirect cost parameters. IPEG4 was recently used at JPL to perform financial sensitivity analyses on the $2.80 Technical Readiness factory. This analysis would have required at least 40 SAMIS runs, but was accomplished by IPEG4 in less than an hour at a total computer cost of less than $100.

The general purpose of IPEG4 is to provide some of the flexibility inherent in the SAMIS model~ but to retain the inherent straightforwardness of the IPEG2 model. IPEG4 can be automatically calibrated by a SAMIS run, or an operator can calibrate IPEG4 independently of SAMIS.

A demonstration of IPEG4 will be given on Thursday afternoon.

9

WU lU

~ t:J

n

a [il u

0

n u

0

0 n u

0 fl u

STATUS OF TECHNOLOGY TRANSFER

The Production Process and Equipment Area is concerned with the transfer of technologies developed by the LSA Project for manufacturers of solar modules. The status of this transfer activity is reported periodically to provide an overview of processes available from JPL, and to promote experimentation, modification, and application. Inquiries and requests for process specifications should be directed to the LSA Project PP&E Area at (213) 577-9225.

Surface Preparation

Process Contractor Status Surveyed By Comments

Texture Etching Lockheed E General Electric Confirmed

E Int'l Rectifier Confirmed

EP Solar Power

Univ. of PA Economic only

Spray A-R Lockheed EP Solar Power

Int'l Rectifier

Spectrolab

Etching Damage MBAssociates EP Solar Power Removal

Int'l Rectifier

Texture Etching MBAssociates EP Solar Power

Int'l Rectifier

CVD Si3N4 Motorola A

Plasma Damage Motorola E Westinghouse Confirmed Etching

EP Solar Power

ASEC

Spectrolab


Wax-Masking Motorola EP Solar Power

Westinghouse


Evaluated 15 Evaluation in Process 34 Available 75 Under Development 0 Suspended 0

Status Code: E - Evaluated; EP - Evaluation in process; A - Available; D - Under development; S - Suspended.

11

Surface Preparation (Cont)


Plasma Metal Motorola EP ASEC Pattern Definition

Solamat

Spray A-R RCA E Photowatt Confirmed

EP Solar Power

Spectrolab

Westinghouse


Si3N4 A-R Coating Photowatt A

Spin-On A-R Coat Photowatt A

Texture Etching Photowatt E Lockheed Confirmed; req. mod.

EP Solar Power


Wafer Surface Photowatt EP Solar Power Preparation


Plasma CVD Photowatt A

Surface Preparation Solarex A

Polish Etching Spectrolab A Rev. A

A-R Coating Spectrolab A

Dip A-R Westinghouse E ASEC Confirmed by Spin-on

EP General Electric

Solar power


12

I .

I I .

I I I I I I .

<

I I I I I I I II I I

fn t]

a " filJj

n n LI

0 0 .

'

a D

fi lliJJ

tll u

a

Process

Ion Implantation

Laser Annealing

Aluminum BSF

Edge Etching

POCI3 Diffusion

Ion Implantation

POCI 3 Diffusion

Ion Implantation

Laser Scribing

POC13

Spray-on Dopants

Post-Diffusion Cleaning

Al Printing Paste Rev. A

Laser Scribing

Polymer Diff. Wafer

Print and Fire BSF Rev. A

Junction Formation

Contractor

Lockheed

Lockheed

MBAssociates

MBAssociates

MBAssociates

Motorola

RCA

RCA

Photowatt

Photowatt

Photowatt

Solarex

Spectrolab

Spectrolab

Spectrolab

Spectrolab

Status Surveyed By

EP

A

EP

A

EP

EP

EP

A

E

EP

A

A

A

E

EP

A

E

E

General Electric

Univ. of PA

Solec Int'l

Solar Power

ASEC

Univ. of PA

General Electric

Solar Power

Mobil Tyco

Spectrolab

Westinghouse

Univ. of PA

Photowatt

Solec Int'l

Westinghouse

ASEC

RCA

Comments

Economic only

Economic only

Confirmed

Confirmed

Confirmed

Economic only

Confirmed

Confirmed

Confirmed

Confirmed

Westinghouse Confirmed

EP General Electric

Photowatt


13

Junction Formation (Cont)


Remove Oxide and Spectrolab E Photowatt Confirmed Clean Al Back

Rev. B

EP Univ. of PA Economic only

Ion Implantation Spire E Motorola Confirmed Furnace Anneal

RCA Confirmed

EP General Electric

Univ. of PA Economic

Spin-on Polymer Texas Inst. EP Univ. of PA Economic Dopants CVD p+ Westinghouse A


14

only

only

I I I .

I I .

I I I I I I II I I I I I I II

" IU

a . I I

a '

I I

[1

0 n tJl

0

n V

a a []

[]

u

Metallization


Al Back Contacts ARCO Solar E Westinghouse Confirmed

EP General Electric

Solar Power

Solec Int' 1

Spire


Thick Film Lockheed EP General Electric


Front Contact MBAssociates EP Solar Power Formation

Electroless Pd/Ni Motorola E ASEC Confirmed

Photowatt Confirmed

Solarex Confirmed

Solar Power Confirmed

Westinghouse Confirmed (Mod.)

EP ARCO Solar

NASA Lewis

RCA

Spire

Univ. of DE Economic only


Plate Copper ASEC A

Thick Film RCA EP General Electric

Spectrolab


Electroless Ni Photowatt EP Solar Power

Spire




15

Metallization (Cont)


Electroless Ni Solarex EP Motorola

Solar Power

Spire



Mo/Sn Metallization SOL/LOS EP Bernd Ross System

Solar Power

Print and Fire Spectrolab E Photowatt Confirmed Front Contact

Rev. A

EP General Electric

Salee Int'l


Silver Printing Spectrolab A Paste


16

IJ I I I I -

I I I I I I I I I I I I I I

n u

a I

'

n u

a I

'

a I I

ITT\ tu

a

a

n u

Module Assembly


Elec. Test and Sort MBAssociates A

Framing MBAssociates EP Solar Power

Lamination MBAssociates EP Solar Power

Module Layout and MBAssociates EP Solar Power Interconnect

Double Glass RCA A

Mass Soldering RCA EP Solar Power

Interconnect and Solarex EP Solar Power Encapsulation

Apply & Cure Spectrolab A Conformed Coating

Applying Interconnects Spectrolab A

Cell Test Spectrolab A

Circuit Assembly Spectrolab A

Final Test Spectrolab A

Frame Module Spectrolab A

Interconnect Cells Spectrolab A

Lamination Springborn A

Laminate Circuit Spectrolab A

Lead Cell Spectrolab A

Mount Cells on Spectrolab A Superstrate & Cure Adhesive

Mount Superstrate in Spectrolab A Frame

String Assembly Spectrolab A

Tin Solder Pad on Spectrolab A Back Al


17

TECHNICAL SUMMARIES

[l i I

n '

!

ft\ u

a

~

u ' .

a I

.

~ I

I .

ff ~

Fl LI

n u

u

fl u

In-House Program

PROJECT ANALYSIS. AND INTEGRATION


Pasadena, CA

An in-depth analysis of Czochralski and HEM ingot technology has been conducted in cooperation with the Technology Development and Production Process and Equipment Areas. Various ingot diameters, sawing methods and degrees of optimism were subjected to detailed SAMIS analysis. The results indicate prices in the approximate range of $0.80/Wp to $1.00/Wp (1980$).

An analytical, closed form, optimal solution has been written for the single busbar grid design (for two design variables). Additionally, an optimizing program written in APL has been used in conjunction with the power loss equations. This program finds the optimal design for two or more potential design variables. Additional solutions and refinements are being pursued for grid designs that require more than one busbar. The grid optimization technique will be incorporated into a procedure for minimizing the cost/watt of the processing steps preceding and following the metalization step which are impacted by the grid pattern design. This work is being performed in cooperation with the PP&E area.

19

n I

'

ffill u n kl

n LI

a 0 a I

/

a a []

u

In-House Program

SILICON MATERIAL TASK

Jet Propulsion Paboratory Pasadena, California

Silicon Processing

The objective of this effort is to provide support to the Silicon Material Task in selected areas.

The two-inch-diameter fluidized bed reactor was modified to improve instrumentation and to facilitate experiments. A series of experiments was then performed to determine how bed clogging would be affected by gas velocity. The results showed that the reactor could be operated without clogging at velocities as low as four Simes the minimum fluidization velocity (i.e., V/V = 4) at 700 C and 10 mole% silane in hydrogen, but the velocity du~fng the initial period of the test must be higher (U/Umf .::_ 7) to prevent clogging.

A paper on "Pyrolysis of Silane in Free Space," which described JPL in-house work in that area, was delivered by Dr. H. Levin in October 1980 at the Electrochemical Society meeting and will appear in the Proceedings.

Feasibility tests for the direct conversion of silane to silicon (Si) were conducted without damage to the apparatus.

In the task for the analysis of impurities using the TSCAP (Thermally Stimulated Capacitance) measurement, the procedure for suitable Schottky diodes is being established in the Silicon Material Research Laboratory. Process improvements were made, and experiments to determine the optimum geometry are underway. TSCAP measurements are being made on these new diodes.

A Zeeman Atomic Absorption Spectrometer, capable of measurements of metallic impurity concentrations in Si in the ppba range was purchased and will be delivered in January 1981. The unit will be operable in February.

In the task for the consolidation of sub-micron Si powder, the experimental efforts were directed to the means of feeding the powder to the melt-pedestal and to ensuring a suitable temperature in the melt zone.

Ralph Lutwack 1-9-81

Approval Signature Date

21

Contract Title:

Contract No. :


AeroChem Research Laboratories, Inc.

Princeton, New Jersey

Development of Processes for the Production of Solar Grade Silicon from Halides and Alkali Metals (Phase II)

955491

The objective of this phase of the program is to characterize the kinetics and mechanism of the formation and growth of silicon particles from the decomposition of silane at high temperatures. The experiments are aimed at determining the rates at which gas-phase species form silicon particle precursors, the time required for silane decomposition to produce silicon particles, and the competing rate of growth of silicon seed particles injected into a decomposing silane environment.

In this reporting period, the AeroChem high-temperature fast-flow reactor (HTFFR), modified to study the decomposition of silane and the subsequent growth of particles, was tested and particle growth measurements were made as functions of temperature (600-1200°C), pressure (50 to 550 Torr), and residence time (0.5-30 ms). Optical diagnostics consisting of attenuation and 90° Mie scattering of the light from He-Ne or Ar+ lasers were used to determine the formation, growth rates, and absolute sizes of the particles. The extent of silane decomposition was measured by infrared absorption spectroscopy. Particles were collected in the observation zone to check the particle concentrations measured optically, and scanning electron micrographs (SEM) confirmed the particle sizes as calculated by Mie theory.

Representative data obtained at 900°C indicate that: (i) Particles formed from silane decomposition have a narrow size distribution and are spherical in shape at a given time in the decomposition/growth process. (2) Silane loss processes (and particle growth) are dominated by heterogeneous gas-particle interactions for sizes greater than 0.05 µm radius. (3) The particle growth rates and silane decomposition rates are consistent with diffusion-limited kinetics in the 50-550 Torr pressure range studied. (4) Tentatively, that particles larger than 0.05 µm radius do not grow by agglomeration. (5) Particles larger than 0.05 µm radius have a cellular structure (from SEM of collected particles). This result and the above data led to the formulation of a simplistic model for the particle growth process.

Our results also provide the particle size, growth rate, and particle concentration data correlations with residence time, temperature, pressure, and silane concentration needed as input to the silane-to-silicon production process.

Approval Signature

22

2 January 1981 Date

I .

I I .

I I ' I .

I I I I I I I I I I I I I

riJ filn

ITT []

a fi u 0

f1l lliJ

ITT ln

a

a []

a fll lU

Contract Title:

Contract No. :


BATTELLE'S COLUMBUS LABORATORIES Columbus, Ohio 43201

EVALUATION OF SELECTED CHEMICAL PROCESSES FOR PRODUCTION OF LOW-COST SILICON

954339

Current activity in the development of the zinc vapor reduction of silicon tetrachloride in a fluidized bed of seed particles relates to the experimental operation of a Process Development Unit (PDU) which consists of four critical units (full scale) from the 50,000 Kg/year EPSDU design, equipped to operate in an 8-hour batch mode.

At the time of the 16th PIM in September of 1980, operation of the PDU had been limited to a few runs of short duration. These and other shake-down activities revealed the need for modifications of equipment design and operating procedures.

During October and a portion of November, a number of such modifications were made to improve operability. These included:

1. Redesign of the inlet and outlet connections to the fluidized-bed reactor to better allow for thermal expansion differentials and to improve sealing.

2. Correction of the condition that caused binding of the graphite reactor inside the outer shell.

3. Modification of the quartz-tube zinc-vapor line to provide greater flexibility.

4. Increase in line diameter and sump capacity, and provision of level indicators to provide for controlled increase flow of recirculated zinc chloride in the wet-wall condenser.

5. General improvement in the design and rigidity of the zinc vaporizer section to avoid equipment breakage and zinc leakage.

As the result of these improvements, it has been possible to eliminate most of the defeating problems that frequently occurred early in the start-up procedure. However, with this improved capability, additional problems have been disclosed, among them a manufacturer's error in drilling the SiCl4 inlet ports of the fluidized-bed reactor, which lead to unacceptably high pressure drop at the higher SiCl4 flows. This problem and others that will be discussed have been corrected in anticipation of runs of full 8-hour duration in January.

23

; )

Date

SILICON MATERIALS TASK

HFiMLOCK SEMICONDUCIDR OORPORATION HFiMLOCK, MICHIGAN 48626

Contract Title: Development of a Polysilicon Process Based on Chemical Vapor Deposition

Contract No. : 955533

The objective of this program is to demonstrate the feasibility of a chlorosilane based chemical vapor deposition process for the production of a low cost-high purity polysilicon. Efforts are currently being expended in the following technical areas:

• Dichlorosilane (ICS) Reactor Feasibility/Optimization • Intermediate Sized DCS Reactor Development • DCS Process/Product Evaluation

• Preliminary EPSDU Design/Integration The experimental reactor feasibility and optimization programs have

been successfully completed. The feasibility of generating high purity silicon from DCS with high conversion and energy efficiencies has now been well established.

Solar cells have been fabricated and evaluated by Westinghouse from material grown in DCS-fed runs. The twenty-five cells included in the test provided an average uncoated AMl efficiency of 9.1% compared to the baseline value of 9.28%. Westinghouse personnel estimated that with AR coatings, the material would produce cells with AMl efficiencies of 12-14%, and considered results to date "quite encouraging."

Construction of the PDU and the DCS feed to an intermediate reactor have been delayed pending receipt of safety-related information about combustion and hydrolytic properties of DCS from experimental work performed by Hazards Research and Dow Chemical Corps. Data from these sources indicate a substantial explosion hazard from DCS/air mixtures, but that the hazard is significantly attenuated if DCS is diluted with hydrogen to make a mixture appropriate for reactor feed. Extensive redesign of both the PDU and intermediate reactor programs have been undertaken to accommmodate the new hazards information.

PDU construction was begun in November; the unit is scheduled for completion in May.

A laboratory scale rearranger system has been utilized in conjuction with an experimental decomposition reactor to determine purity of silicon generated for the liquid phase redistribution of trichlorosilane by Dowex ion exchange resin MWA-1. All electrically active impurities in the silicon were determined to exist in concentrations less than 1 ppba.

An economic analysis of a 1000 tonne facility based on DCS technology has indicated a capital requirement of $21.9 Rand a product price of $18.95/kg silicon.

; > Approval si6nature Date

24


fl I '

a .

'

!] 1 '

.

a .

.

n IJ

fl u

a

TASK I SILICON MATERIAL

Massachusetts Institute of Technology Cambridge, Massachusetts.

Contract Title: Investigation of the Hydrogenation of Sic14

Contract No.: 955 382

A research and development program was initiated in April of 1979 to study the nydrochlorination of silicon tetrachloride and m.g. silicon metal to trichlorosilane,

3 SiC14 + 2 H2 + Si 4 SiHC13

This two-year contract is conducted as a complementary program to supplement the engineering process development activities for the process-unit under Union Carbide Contract No, 954 334. As this contract work progresses satisfactorily on schedule toward the expiration date on March 31 of this year, most of the major objectives of this contract have been accomplished, A summary of the accomplishments on the overall program is presented. The potential commercial application of this rather unique hydrochlorination reaction for the existing polycrystalline silicon metal industry is also discussed,

Activities in the current period include a prolonged experiment carried out with the object of studying the life of the silicon mass bed. After about 238 hours of reaction, no significant change on the reaction rate was observed. A material balance of 92,2% was made on silicon. These results confirm the stoichiometry of the hydrochlorination reaction as written in the above equation, A corrosion study was made on Incoloy 800 as the material of construction for the hydrochlorination reactor, No measurable amounts of corrosion on this material was observed when a test sample was exposed to the hydrochlorination reaction for 238 hours at 500°C, JOO psig. A stable silicide protective film of approximately twenty microns thick appears to be formed on the Incoloy 800 metal surface. However, this protective film is highly reactive toward air and moisture when it is exposed to the atmosphere. The serious corrosion problem as previously reported on the material of construction for the hydrochlorination reactor appears primarily due to atmospheric corrosion and not due to the reaction enviroment itself, As the present study indicates, Incoloy 800 is a good choice as the material of construction for the hydrochlorination reactor.

1fr81 , Date

25

Contract Title:

Contract No.: 954334


UNION CARBIDE CORPORATION

Tonawanda, New York 14120

Silane-to-Silicon EPSDU

Construction of the 100 Kf/Y EPSDU at East Chicago, Indiana is continuing. A subcontract was awarded in late September, 1980 for all civil and structural work. As of December 31, all foundations for equipment and structures were completed and the structural steel for the process gantry was erected. All underground utilities and service lines have been installed including 12.5 KV primary power, yard lighting, natural gas, nitrogen, hydrogen, potable water, cooling water, fire/emergency water, process waste drains, and sanitary drains. The civil-structural subcontract will be completed in mid-February, 1981 with installation of two pre-engineered structures - the switchgear/control room and the melter building.

Fabrication of process and auxiliary equipment for EPSDU is progressing well, with many items scheduled for final inspection and delivery in January and February, 1981. Equipment is arriving at the job site; larger items are being placed in position while smaller items are being stored during the winter months.

EPSDU engineering activities on detailed drawing-spec packages for all mechanical and electrical subcontracted work are nearing completion. These subcontracts will be awarded this Spring and will include installation of all equipment, piping, tubing, insulation, power wiring, and instrumentation wiring.

The free-space reactor PDU work was successfully completed after demonstrating long-term operability of the reactor. Three 12-hour runs and several shorter runs verified reliable operation. A polycrystalline boule pulled from the melted powder exhibited a resistivity of 55 ncm, P-type, which indicates that the free-space pyrolysis process maintained the purity level of the silane feed. Fabrication of an alternate silane pyrolysis PDU using a fluidized bed was completed and installation is underway.

Melter subcontract work with Kayex Corporation is proceeding well, although it is somewhat behind schedule. Most of the major components for the silicon shatter were procured and assembled. System checkout and preliminary melting tests using chunk silicon will start soon.

Approval Signature

26

Ii II

I .

.

I I I I I I I I I I I I I I I I I

n fiJ LB

[] ' .

In-House Program

LARGE AREA SILICON SHEET TASK



(1) Silicon Crystal Growth Laboratory:

Crystal growth work on silicon bicrystal with varying grain orientation is continuing. Experiments on crystal growth with impure silicon is in progress. Variation of crystal growth furnace temperature profile is being tried for growth experiments.

(2) Photovoltaic Materials and Device Testing Laboratory:

The following work is in progress:

(a) Experiments with bicrystals using static and transient capacitance and conductance measurements.

(b) Minority carrier lifetime and surface recombination velocity measurements using SEM with beam blanking.

(c) Oxygen, and carbon content analysis of low-cost sheet using IR absorption spectroscopy.

(d) Recombination mechanism studies utilizing dark IV and EBIC results on various silicon sheet material.

(e) Evaluation of low-cost sheet materials using high energy electron irradiation technique.

(3) Solar Cell Prototype Fabrication Laboratory:

Routine fabrication and testing of solar cells made from different low-cost sheets is continuing.

01/05/81 Approval Signature 27 Date

IAR:;E ARhA SILIC0:1 SHEEr TASK

Applied Solar Energy Corp. City of Industry, Calif.

Contract Title: Silicon Solar Cell Process Developtent, Fabrication and Analysis

Contract No: 955089

The objective of this program is to investigate, develop and utilize technologies appropriate and necessary for mproving the efficiency of solar cells made fran various unoonventional silicon sheets. Silicon sheets processed included EFG (M:>bil-Tyco), dendritic Web (Westinghouse) and HEM (crystal systen) •

Solar cells were fabricated using a baseline process. Performance was evaluated under AMl illumination oondi tions. In addition, back-up neasurenents were made of minority carrier diffusion length, spectral response, dark diode I-V characteristics and small light spot scanning. Good agreerent was found between these back-up measurements and the cell perfonnance. Solar cells made from EFG riboons grown in CO-on and CO-off envirornnent and the performance r-esults were canpared.

Other process variations (in efforts to improve cell perfonnance), such as fonnation of shallow junction with fine grid lines, BSF and better AR coating were applied on dendritic web. I.cM temperature ( - 600°C for about 30 hours) anealing was applied on EFG riboons. Efforts were made to passivate grain boundaries by bJo step diffusion (using EFG, snso and Poly CZ) and gettering by diffusion glass (HEM). The results will be reported.

Baseline solar cells were fabricated fran a large cast ingot (HEM, "'40 Kg) and detailed mapp-ing of the cell perfonna.nce will be presented.

APPROVAL SIGNA'IURE

28

January 5, 1981

DATE

I I .

.

Ii I

I I I I I I I I I I I I I I I I

a .

.

frll Li

(] '

.

rn bJJ

Fil u

fl Li

[]


CORNELL UNIVERSITY

ITHACA, NY

Contract Title: Characterization of Structural, Electrical and Chemical Properties of Slicon Sheet Material


In the period 9/25/80 to 12131/80 we analysed processe~ and unprocessed EFG ribbons, WEB ribbons and HEM cast ingots by optical microscopy and etching, EBIC (electron beam induced current microscopy), TEM (transmission electron microscopy) and HVTEM (high voltage transmission electron microscopy at 1.2 MeV). The results are :

(a) EFG material

(1) In general, the electrical activity of coherent twin boundaries exhibiting dotted EBIC contrast is caused by the presence of partial dislocations in the boundary. Occas:bnally, we observe partial dislocations which are not electrically active. Safar it appears that the electrically active partials tend to be curved and the non electrically active partials tend to be straight (which suggests kinks as the cause of electrical activity) but impurity based explanations are also possible.

(21 Hydrogen passivation greatly reduces the activity of deformation induced dislocations, but is less effective in reducing the activity of ingrown dislocations .

(3) TEM analysis of the dislocation networks in procesed EFG is continuing.

(b) WEB material

(1) The misfit dislocation network contained in the internal twin boundaries has been studied in detail with EBIC. Almost all dislocations are electrically active, with Lamer Cotrell dislocations being the most prominent.

(cl HEM material (.11 EBIC and etching studies of grain boundaries show a one to one correlation between recombination sites and the presence of dislocations. The boundaries examind sofar were not intrinsically electrically active. Beautiful examples of faceted grain boundaries were observed, indicating that the boundaries are in a low energy configuration and well equilibrated.

Approval Signature

29

J 2131 /HQ Date


CRYSTAL SYSTEMS, INC.

SALEM, MA ')1970

Contract Title: SILICON INGOT CASTING--HEAT EXCHANGER METHOD (HEM) /MULTI

WIRE SLICING--FIXED ABRASIVE SLICING TECHNIQUE (FAST): PHASE


This contract is for casting silicon ingots by the Heat Exchanger Method (HEM) and slicing by multi-wire Fixed Abrasive Slicing Technique (FAST).

It has been demonstrated that large silicon ingots up to 34 cm x 34 cm x 20 cm weighing 45 kg can be cast by HEM. The crucibles had curved bottoms and rounded corners resulting in reduced square cross-sections. A new crucible with a flat bottom and square corners has been developed which will produce an 86% yield after sectioning the ingot into bars.

The projected add-on cost for meeting the goal of casting 30 cm2 ingots was $8.50/m2

, much less than the allocation of $18.15/m2• Cost projec

tions show that casting of 35 kg ingots would be sufficient to meet the DOE goal of $0.70/watt in 1986, and therefore the program has been redirected. The emphasis of the program now is to optimize the material quality with an ingot size of 35 kg to yield 9 bars 15 cm long and 10 cm x 10 cm cross-section.

Detailed ch&racterization of two ingots has shown that post-solidification he~t treatment has significant effect on the solar cell performance. Another area of optimization is to control the heat flow to achieve single-crystallinity across the bottom of the ingot. Considerable effort has been placed in studying the annealing cycle and improving crystallinity of the cast ingots. A 30 cm x 30 cm x 15 cm ingot has been sent to JPL for detailed characterization.

The new bladehead installed on the FAST slicer has improved performance. The average slicing rate during slicing of three 10-cm diameter silicon ingots was 3.8 mils/min, 0.097 nun/min, with this modification, as against 2.2 mils/min, 0.056 nnn/min achieved earlier.

Emphasis during the present period has been on blade development. Since it is now possible to electroplate diamonds in the cutting edge and this blade is better than impregnated wires, most of the effort has been concentrated on electroplated wires. It has been found that masking techniques to selectively electroplate diamonds on wires produce flats which do not allow the seating of the wires in the grooved rollers during slicing. Other techniques such as electroforming are presently being pursued.

Crystal Systems has set up a plating facility to achieve better reproducibility and to correlate the plating variables with the slicing performance. Slicing tests with such a bladepack already resulted in a

9(121~~, ;;LJ Approval Signature

30

I I I

IV

I I I I I I I I I [I

I I I I I I

~ ~ ~

n '

I

~ ~ ~

n ~

a I

.

~ ~

~ ~

~ ~


HONEYWELL TECHNOLOGY CENTER BLOOMINGTON, MINNESOTA 55420

Contract Title: Silicon-On-Ceramic Process


Since the last PIM, SCIM-coating of fully slotted 10 cm x 100 cm substrates has been achieved. Numerous coater modifications and refined coating techniques contributed to this accomplishment. Considerable progress was made toward minimizing problems which have in the past limited the success of the SCIM-coating technique. One of the more serious of these problems was related to substrate warpage and breakage. Optimization of longitudinal temperature profiles in the pre and post heat zones of the coater has for the most part eliminated this problem. Likewise, improved transverse temperature uniformity has also contributed to more uniform silicon layers. A careful study of growth parameters has also improved coating reproducibility from run to run. The silicon layers produced by SCIM-II have good thickness uniformity except for dendritic regions th~t tend to occur all along the coating. These dendritic regions are not characteristic of coatings produced in SCIM-I and may, therefore, be related to the oxygen level in the SCIM-II coater. They frequently can be eliminated by blowing argon on the meniscus.

Due to the continuing need for changes in the carbon parts, purified parts have not been installed in SCIM-II. The design has now been frozen and purified parts have been ordered. Because of these impure carbon parts, the best cell results are still being achieved with dip-coated substrates. For dip-coated cells, the best cell so far has a total area conversion efficiency of 10.54% (AMl,AR) for a cell area of 5 cm2. This cell was produced from SOC material grown in an argon-hydrogen environment rather than a pure argon environment. The 25% hydrogen gas seems to increase cell performance but more work is needed to verify this preliminary result.

For SCIM-coated cells, the highest cell efficiency is 7.64% (AMl,AR), for a cell area of 5 cm2. The short-circuit current density is 20.2 mA/cm2, as compared to 25 mA/cm2 which is typical for dip-coated SOC cells. This lower Jsc is to be expected on the basis of earlier dip-coating results on material grown with impure carbon parts.

Work on SOC during 1981 will be continued under SERI funding as part of the Exploratory Development Program. Three approaches will be compared: (1) SOC using semiconductor grade (SG) silicon, (2) epitaxial layers on heavily-doped SOC substrates using SG silicon, and (3) epitaxial layers on heavily-doped SOC substrates using refined metallurgical grade (RMG) silicon. The final report on the present contract is under preparation.

oval Signature 31

Contract Title:

Contract No. :


KAYEX CORPORATION

ROCHESTER, NEW YORK

Development of an Advanced Czochralski Growth Process to

Produce Low Cost 150 kg· Silicon Ingots from a Single Crucible for Technology Readiness

955733

A unilateral modification to JPL contract number 954888 was issued in April, 1980 to enable the design phase of the crystal grower to be undertaken. This design phase was successfully completed by December, 1980.

JPL contract number 955733 was issued in September, 1980. This contract comprehends the building and process development of a crystal puller suitable for demonstration of technology readiness rapidly transferrable to industry.

To date, the ordering of all the puller components and the necessary raw materials for process development has been completed and assembly of the crystal puller has connnenced.

The crystal puller has been designed to acconnnodate crucibles of up to 16-inch diameter and will be interfaced with microprocessor controls to automate the crystal growth process. The contract also allows for development of various sensors to aid process control, i.e. melt level, continuous diameter measurement.

A radiation shield will be utilized as a method of achieving accelerated growth rates.

An investigation of impurity build-up and its effects on ultimate crystal purity and fabricated solar cells will be undertaken.

Design/analysis studies using SAMICS FORMAT A techniques will be ma.de during the process development phase of the contract to enable identification of cost elements and their effect and impact on CZ add-on cost.

12/29/80 '.Approval Signature Date

32


n I '

W11 lH

a

"11 fi~

Frfl ~

a

~ '

.

[] ' .

u

Contract Title:

Contract No. :


Mobil Tyco Solar Energy Corporation

Waltham, Massachusetts 02254

LARGE AREA SILICON SHEET BY EFG

954355

Crystal growth experiments in furnaces 17 and 18 have continued to investigate factors influencing the quality of 10 cm wide ribbon grown at speeds of 3 to 4 cm/min, The more recent work has focussed on improving the means of introducing oxygen into the ribbon, both through the use of quartz in the bulk melt and by ambient manipulation, and on studying the effects of resistivity on solar cell performance. A new interface gas distribution system has been tested, which achieves control of the interface ambient composition by the use of a hollow dietop shield. This work has been combined with a study of the effectiveness of an alternate means of introducing oxygen to the ribbon - by intentionally adding quartz to the bulk melt, Growth of ribbon from melts doped to 1 and 5 n-cm is also in progress in conjunction with the work on control of ribbon oxygen content.

The solar cell performance of ribbon grown with and without CO and COz present in the meniscus ambient is similar to that already reported in experiments at slower growth speeds. Top cell efficiencies for the 10 cm wide ribbon range from 10 to 11%, and so have not reached the levels of 12 to 13% attained earlier. The results of adding quartz to the bulk melt and effect of resistivity variations on cell performance will also be reported,

In furnace JPL no. 3A, the multiple equipment, further engineering work was continuing toward reaching the "technical features demonstration," in particular with respect to throughput. The problems to be overcome are related chiefly to the temperature distribution along the main furnace heating elements. Progress has been made in this area to the extent that on Dec. 10, 1980 a reasonably successful multiple run very nearly demonstrated all the technical features, During 5 hrs and 21 min of running, ~19 m of 10 cm wide ribbon were produced at an average growth speed of 3.3 cm/min. The center cartridge performed absolutely flawlessly; it ran for 5 hrs and 17 min without problems under automatic control. The two other cartridges, because of the above mentioned problems were not yet as stable so that simultaneous automatically controlled growth in all three cartridges was achieved only for a period of 1 hr. 10 min.

Approval Signature

33

1tt-. I 11 / 10 r· Date

Contract Title:

Contract No. :


SEMIX INCORPORATED

GAITHERSBURG, MD

Semicrystalline Casting Process Development and Verification

DE-FC01-80ET 23197

"Semicrystalline Casting Process Development and Verification" is a three year Cooperative Agreement oetween Semix Incorporated and the United States Department of Energy. The goals of this Agreement are to demonstrate the commercial readiness of a silicon sheet manufacturing process compatible with the 1982 price goal of $2.80 per peak watt and to demonstrate the technology readiness to meet the 1986 price goal of $.70/Watt.

Since the last Project Integration Meeting extensive economic analyses utilizing SA1-IICS methodology have been carried out indicating that the Semix Ubiquitous Crystallization Process (U.C.P.) exceeds the United States Department of Energy price goals for 1986. In addition, the U. C, P. compares favcrrably, 'fo.r 19..82 and frozen 19.82 tecfule::,logy-,

Work has progressed in designing and developing the required critical subsystems and construction of key prototype equipment is on schedule.


~ I l {ft! u

[] . '

a '

I

fl! u

a j

~ ' 1

Contract Title:

Contract No. :

LSA LARGE AREA SILICON SHEET TASK

Siltec Corporation Menlo Park, California

CONTINUOUS LIQUID FEED CZOCHRALSKI GROWTH

DOE/JPL-954886

This project is directed toward the design and development of equipment and processes to demonstrate the continuous growth of crystals, via the Czochralski method, suitable for producing single-crystal silicon for use in solar cells. "Continuous" is defined as the growth of at least 150 kg in monocrystalline ingots, 150 mm in diameter with 50 kg minimum weight per ingot, obtained from one growth crucible.

Our approach in meeting this goal is to develop a furnace with continuous liquid replenishment of the growth crucible. This has been accomplished through the use of a meltdown system with a continuous solid silicon feeder and a melt transfer mechanism with associated automatic feedback controls.

After demonstrating the capability of pulling several ingots >50 kg from one melt in the previous reporting period, the most recent efforts were aimed at identifying and controlling process variables on a higher level of process performance to achieve optimum monocrystalline yields.

Progress was made in the performance of automatic diameter control for ingots >125 mm with diameter variations of ±380 µm.

A significant increase in monocrystalline yield was achieved through better control of thermal convection currents in the melt of the growth crucible.

The melt transfer system was further simplified through various design improvements of the super insulation, the heating elements, and the temperature control of the replenishing melt stream.

Preliminary material analysis has shown great consistency in impurity levels (e.g., carbon, oxygen and other impurities) in material obtained from the CLF-CZ furnace.

The overall design for the production prototype CLF-CZ furnace, in order to meet 1982 technical readiness goals, has begun, incorporating Siltec's new microprocessor-controlled AG660-CZ growth furnace.

/·- 6 - !9fl/

Date

35

Contract Tit I e :

Contract No. :

LSA LARGE AREA SILICON SHEET TASK

Siltec Corporation Menlo Park, California

ENHANCED I.D. SLICING TECHNOLOGY

DOE/JPL-955282

The goal of this program is to enhance I.D. slicing technology so that a significant increase in the number of usable slices per inch of ingot over industry practice can be achieved. A reduction of both blade and slice thickness is required, necessitating the introduction of several new technologies.

Extensive experimentation in I.D. slicing with ingot rotation was performed during the final months of this program with the following results: Severe limitations were experienced in trying to produce slices of 250 µm thickness with economic cutting feed rates of 211 /min due to the combination of unisotropic material characteristics of monocrystalline silicon and ingot rotation during slicing. A harmonic ingot feed mechanism coordinated with the cutting direction of the ingot is required to eliminate the fracturing problem. This measure, however, reduces the throughput rate below the level of a cost-effective operation. The best results achieved consistently with ingot rotation were produced with 100 mm diameter slices, 250 µm thick, with a kerf of 200 µm and a feed rate of 15 rrm/min. These results were improved by increasing the size of the cutting head, thereby lowering high frequency vibrations during slicing.

The effectiveness of the cutting edge position control system was successfully demonstrated in all experiments, particularly when cutting wfth low kerf (152-200 µm} blades. For a given set of operating parameters, the deflection of the cutting edge could typically be reduced by one order of magnitude through the control device.

New blade constructions for low kerf slicing were further investigated. The blade construction with the prefabricated cutting edge insert has great potential; however, it requires more fundamental work in the materials area of the bond to become an effective production tool. The alternative solution of etched core construction has shown good results, although further refinement in order to improve lifetime is required.

A comparison of slicing with ingot rotation and plunge cutting indicated that straight cutting with simultaneous multiple ingot feed will improve the present picture of I.D. slicing significantly.

/- t,- 191/ /~ prcJ'al Sign#re Date .,

36


rfll u lfr1 u

a fll tJ

ITT! u

~ I

'

[] ' ' fl Li

n u

r1 tU

Contract Title:

Contract No. :


SILICON TECHNOLOGY CORPORATION

OAKLAND, N.J.

I.D. WAFERING OF SILICON FOR SOLAR CELLS

FY-730105

The purpose of this contract is to evaluate state-of-the-art I .D. Wafering technology for wafering of 6-inch diameter single crystal silicon and 4-inch square silicon suitable for terrestrial solar cells. A standard 22-inch STC I.D. Saw, equipped with progra:mmable feed and crystal rotating capability and a prototype I .D. Saw (RD-140) capable of cutting up to 8-inch diameter silicon have been used to perform the slicing tests.

To date, we have been able to slice 6-inch diameter silicon at a thickness of 12.5 mils with 13.5 mils kerf loss. Maximum cutting rates were 1.75 inches per minute with 90% yield. The rotation experiments were less successful on 6-inch diameter silicon. Although kerf loss was only 11 .5 mils, we were not able to achieve satisfactory yields on wafers below 17 mils in thickness. Maximum cutting rates were .5 inches per minute. The main problem is edge chipping and wafer breakage during the cutting stroke. The 6-inch diameter silicon exhibits considerable difference to slicing parameters than 4-inch diameter silicon.

Future plans include development of rotation and feed programs to improve rotational slicing of 6-inch diameter silicon.

We also plan to improve the performance of the RD-140 machine by:

1) Modification of the blade mount, 2) Improving mounting techniques, 3) Redesign of blade mount enclosure to reduce turbulence, 4) Experiments on slicing 4-inch square silicon.

12/31 /80

Date

37

LARGE AREA SILlCON SHEET TASK

University of Missouri - Rolla Rolla, Missouri

Contract Title: Measurement of Oxygen Partial Pressure in JPL LSA Contractors' Silicon Sheet and Ribbon Production Facilities


A thoria-yttria solid electrolyte oxygen sensor was transported to the Westinghouse dendritic web silicon growth facility (Pittsburgh, PA) for the purpose of measuring the levels of oxygen in their silicon web furnaces. The p02 of their argon purge gas supply was measured (in the 10000c oxygen cell) to be 10-12.5 atm., and approximately the same value was obtained when the silicon web was being grown (at 1420°c), varying only slightly with the purge gas flow rate.

Similar measurements were made at the Honeywell silicon-on-ceramic (SOC) facility (Minneapolis, MN) using a zirconia-yttria oxygen cell. The p02 og the house argon purge gas supply was measured to be 10- atm., or about 1 ppm. With the SCIM coater at temperature J14200C) with no ports open, the p02 dropped to about 10-l atm. as measured at 10000c in the oxygen cell. This increased to 10-13.2 atm. when a port was opened to atmosphere for boron doping and silicon melt replenishment. The p02 varied between these values as the ceramic substrate was being coated, higher oxygen levels occurring when the ceramic substrate entrance and exit gates were opened, returning to lower values after the soc was removed and the gates were closed.

The Ho~e~ell DIP furnace purge gas indicated a po2 of about 1(T't• atm., or 15 ppm, but values similar to those in the SCIM coater, i.e., about 10-15.5 atm., were obtained with the furnace at operating temperature, dropping to 10-13.2 atm. when new samples were inserted, with excursions to 0.1 atm. when it was necessary to retrieve a broken sample.

For comparison, the p02 (measured at 1000°c) in the Mobil-Tyco (Waltham, MA) EFG silicon ribbon furnace has been previously reported to be 10-12.1 atm.

38

January 2, 1981 Date


a I.

Fl u

a '

r

fil kJJ

a '

'

[]

u '

'

r1l fu..cl

a <·

a ' .


Westinghouse Research and Development Center

Pittsburgh, PA 15235

Contract Tit I e : ADVANCED DENDRITIC WEB GROWTH DEVELOPMENT

Contract No.: DOE/JPL 955843

This program started October 22, 1980 and among its several tasks includes a continuing design of an advanced web growth design effort begun under now-completed JPL contract 954654. The design includes both mechanical and electronic control features of the apparatus as necessary to satisfy the functional and equipment cost requirements identified by economic analysis.

The design of the mechanical system is complete except for refinements to minimize equipment cost. These refinements are confined to the fit and function of the existing design and will not alter either the function or the operation of the apparatus. The design of the electronic control system is less complete, awaiting experimental verification of some of the design elements. As with the mechanical design effort. refinements of the electronic design to minimize equipment cost are in progress.

Another major task of this program is enhanced web throughput, an effort underway in several areas. Additional growth speed has been obtained from a known high speed thermal configuration by reduction of the lid thickness, thus providing more effective removal of the heat of fusion from the growth region. This change also modifies the vertical temperature profile and increases the thermal stress, a condition which is corrected by adjustment of the heat shields, now in progress.

Also, for enhanced throughput, computer models are being developed for the effect of temperature profiles on both the "plastic" thermal stress (responsible for residual stress) and "elastic" thermal stress (responsible for deformation). Also, a criterion is being determined for the maximum thermal stress that can exist without causing buckling of the web ribbon. This model will aid in the thermal design of growth configurations for increased si~ultaneous width and speed (throughput).

Several lid/shield thermal configurations are being investigated with the goal of growing web at constant width for very long lengths with continuously replenished melts. One design concept produces ribbon of about 3 cm width, but requires additional trimming of the temperature within the melt, an effort now in progress. This configuration is similar to that of the high speed growth system such that the two systems may be readily integrated. When development of the 3 cm width control system has been completed, the concept will be applied to widths in the 4 to 5 cm range.

Approval Signature Dote

39

f1I ld

n fun

ITTll fu j

fff lli-11

ITT] tu

[] I I '

~ I '

Fl tJJ

LI

LI

In-House Program

ENCAPSULATION TASK

Jet Propulsion Laboratory Pasadena, California

Material Degradation and Life Modeling

Developing quantitative relationships that relate environmental stress such as solar ultraviolet, wind, temperature extremes, and moisture to the rate of degradation of module performance and structural integrity are objectives of the Encapsulation Task in-house efforts. These activities are integrated with contractual activities to develop an over-all module life prediction method.

Photothermal degradation rates and mechanisms and ultraviolet absorption characteristics of polymeric encapsulants are being measured as a function of polymer composition and test exposure conditions. Data are being obtained for silicones, FNA, P-nBA, polyurethane, and acrylic films. Additional materials will be characterized during the coming year. Failure mechanisms and critical temperature limits associated with module hot cell experience are being identified for use in establishing module circuit design and diode protection criteria.

Modeling of the pho~degradation of UV screening acrylic outer cover films has yielded rates of degradation of the material constituents and of the total system. These data have been used to provide material composition criteria for the achievement of optimum low-cost long-life cover films.

Encapsulation material degradation data for low-cost advanced encapsulant systems is being gathered using various test hardware such as mini-modules (12" x 16"), two-cell modules and individual material samples. Exposure facilities include JPL laboratory test chamber and selected California field test sites at Point Vicente, JPL, Goldstone, and Table Mountain.

A JPL-LSA (5101 series) report is being written which will describe the encapsulant material requirements for the various functional elements of a complete photovoltaic module encapsulation package. This information will be presented in terms of material properties, performance, life and cost requirements. It will describe the status and availability of potential material and process candidates with criteria and guidelines for their selection, processing, and optimizing configurations for specific applications.

t!:~if~~!&~ ,Approva1 Signature

41

Jan. 8, 1981

Date

ENCAPSULATION TASK

CASE WESTERN RESERVE UNIVERSITY CLEVELAND, OHIO

Contract Title: Systems Studies of Basic Aging and Diffusion


The objective of this study is to establish the kinetics and mechanism of thermal and photo-oxidative degradation of candidate encapsulation materials for the LSA Project. That information is to be used to develop accelerated testing and life performance prediction methods and to guide the continuing selection of optimum performance encapsulation material systems. The study is being carried out in cooperation with related studies at JPL.

The present work is aimed towards establishing the modes of degradation of poly(n-butylacrylate)(PNBA) and their effects on selected chemical and physical properties. It has been found that for PNBA: 1. Extensive gel formation is obtained after 425 hours exposure in the QUV weatherometer. The crosslink density of this gel is less than 1%. 2. A study of the dynamic mechanical properties by torsion-braid analysis shows an 8°C increase in the glass transition temperature (Tg) for a sample exposed to the medium pressure mercury lamps for up to 160 hours. This Tg shift indicates the formation of a network with a crosslink density of about 2%. 3. Spectroscopic analysis of PNBA films indicates that long term (2300 hours in the QUV) photo-oxidation results in a 40% loss of the butyl ester group. New absorbance bands are formed during photo-oxidation to indicate a conversion of the ester to in-chain alcohols, carboxylic acid and a lactone.

Continuing studies include. the determination of: 1. Changes in polymer mass, molecular weight and its distribution (including network structure) and chemical composition after very long tern exposure. 2. The quantum efficiency of the reactions. 3. Changes in polymer flow (creep), dynamic-mechanical properties, and other relevant physical properties related to continuing crosslink formation (and -other degradation modes) upon exposure. 4. Spectroscopic analysis of model compounds related to probable degradation products and comparison with the spectra of degraded films. 5. The validity of predictions of long term exposure performance based on short term testing.

1/6/81

Date

42


~ fil_~

[]

a ' .

n u f) u

a

~ . .

~ . .

u

Contract Title:

Contract No. :

Encapsulation Task

Illinois Tool Works, Inc., Venture Group

Elgin, IL

Ion Plating of Solar Cell Arrays

955506

The ITW contract was initiated in December 1979 to investigate, develop and demonstrate the capability to produce operational solar cells having metallizations and AR coatings deposited by gasless ion plating, which will separately and/or in combination with a low cost encapsulation system meet the LSA project life, cost and performance goals.

Present work has been focused on developing metallization systems, which when deposited by ion plating will yield an acceptable ohmic contact (contact resistance~ .160 Q•cm2) to nondegenerate silicon surfaces. A Ti-Cu composite film has been shown to produce a contact with a resistance of ~.120 Q•cm2 when deposited on n-type silicon (phosphorous doped, p=1~2 Q•cm). More recently, a Ti-Al alloy has been developed that when deposited on p-type silicon (boron doped, p=6~12 Q•cm) will yield an ohmic contact with a resistance of "'. 11 O n • cm2 •

With the development of materials which provide ohmic contacts to nondegenerate silicon, a major hurdle has been cleared in the ongoing metallization program. A masking fixture is being designed for 3" diameter wafers having phosphorous doped junctions in p-type base material. 4" diameter wafers with boron doped junctions in n-type base silicon have been metallized utilizing copper as the current carrying material. Preliminary data indicated that these cells are as good as production cells. Complete test results will be presented at the PIM.

t - s- 81 Date Approval Signet

43

Contract Title:

Contract No.:

ENCAPSULATION TASK

ROCKWELL INTERNATIONAL SCIENCE CENTER

THOUSAND OAKS, CALIFORNIA

Study Program for Encapsulation Materials for Low Cost Solar Arrays

JPL Subcontract No. 954739

The major objectives of this study are to conduct a physical/chemical study of surface and interface degradation in solar cell encapsulant systems induced by moisture, temperature, and UV radiation. One current effort, which nears completion, is focussed on developing corrosion monitors as nondestructive evaluation (NDE) tools for LSA life prediction. A second effort is directed toward developing corrosion models and materials selection criteria for environment and corrosion resistant interfaces.

Atmospheric corrosion monitors (ACM) have been returned to the Science Center following 13 months deployment at the Mead, Nebraska test site. During this period the ACM units recorded the corrosion protection function of an encapsulant system and correlated Mead climatology with corrosion rates of a nonencapsulated ACM. The fundamental assumptions of a new atmospheric corrosion model were verified in this study. This corrosion model predicts that corrosion rate is the product of a condensation probability (Pc) and the maximum ionic diffusion current (IL)• Encapsulant corrosion protection is specifically related to its efficiency in suppressing IL at the potential corrosion interface.

AC impedance measurements combined with impedance spectrum analysis and feed back control to a branch circuit appear as a direct means of remotely locating degraded LSA modules and modifying series to parallel S/P interconnects between modules to achieve maximum LSA power efficiency.

A hydrothermal stress analysis (HTSA) computer model has been successfully applied to evaluate the combined effects of temperature-humidity cycling on development of internal stresses and solar cell cracking in solar cell modules using a fiberboard substrate. The effect of protective polymer coatings of ethylene vinylacetate (EVA) and polytrifluoro-chloroethylene (Kel-F) is to delay but not change the failure process.

A new materials selection criteria for encapsulant bonding is being developed which incorporates both ionic conduction and electrochemical mechanisms of corrosion. The new selection criteria and test methodology is specifically directed at suppressing the micro-corrosion process in the presence of internal defects such as micro-cracks.

Approval Signature

44

L4n ~, /PtPI >

Date


tfJI [j

n a .

.

a I .

a a

~ I '

D I .

ITT! kJJ

[]

r, lY

Fl u

rTI mJ

Contract Title:

Contract No. :

ENCAPSULATION TASK

Spectrolab, Inc.

Sylmar, California

The Design, Analysis, and Test Verification

of Advanced Encapsulation Systems

955567

The objective of this program is to develop analytical methodology for advanced encapsulation systems which will aid in the determination of optimum systems for meeting the Low-Cost Solar Array Project goals.

During this period optical, thermal, electrical, and structural analytical models have been finalized and documented.

Work has begun on Phase II of the program which will test the models developed in Phase I by manufacturing modules and test coupons and subjecting them to environmental stresses. A test plan for this phase has been developed with cooperation of JPL and module construction is underway.

ENCAPSULATION TASK

Spire Corporation Bedford, Massachusetts O 17 30

Contract Title: INTEGRAL GLASS ENCAPSULATION FOR SOLAR ARRAYS


This program is aimed at the development of electrostatic bonding (ESB) as an advanced encapsulation technique for terrestrial solar arrays. The electrostatic bonding process is used to join cells directly to the module front glass without use of adhesives or other organic materials. A variety of module designs combining this integral front structure with either electrostatic bonding or conventional processing for back encapsulation have been developed.

Three types of modules being developed under this program are:

• Integral front - Conventional cells are electrostatically bonded to glass sheets to provide hermetic and permanent sealing of the cells to module fronts. Ordinary encapsulating procedures are used to protect the module back.

• Preformed contacts - Silicon wafers containing p-n junctions but no front contact metal are electrostatically bonded to glass fronts. As part of this process wire screens are trapped between the glass and wafers to provide the front contact and eventually the cell to cell interconnects. Conventional back encapsulation is employed.

• Low temperature ESB Planar front surface cells are electrostatically bonded to large area glass sheets on a hot plate type of bonder. Capital equipment requirements for this process are negligible.

During the current period ESB minimodules have been fabricated. A total of 10 integral front ESB minimodules, each containing 24 series connected cells, have been made and delivered to JPL for testing. Cell efficiency in the completed modules have consistently been above 12.596.

Three 24 cell preformed contact minimodules (out of five scheduled to be delivered) have been fabricated. Efficiency of multiple cell assemblies fabricated in this manner exceeds 996, and individual cell performance is significantly higher.

Five 12"x19" samples demonstrating the feasibility of low temperature ESB have been fabricated and delivered to JPL for test.

Date

46

I .I I I I I I I I I I I I I I I I I I

n .

I

a

a fl Li

tn LI

0 n '

.

Will filJl

fl LI

~.

PRODUCTION PROCESS & EQUIPMENT DEVELOPMENT (TASK 4)

Contract Title:

Contract No.:

Spire Corporation Bedford, Massachusetts 01730

DEVELOPMENT AND FABRICATION OF A SOLAR CELL JUNCTION PROCESSING SYSTEM

DOE/JPL 955640

22 August - 31 December 1980

The objectives of this program are to design and build equipment capable of ion implanting and pulse annealing junctions for 4-inch-diameter solar cells. Wafers will first pass under a phosphorus ion beam and then under a pulsed electron beam at the rate of 1800 wafers per hour in a cassette-to-cassette mode. The wafers are transported in vacuum by means of a "walking beam" which uses no oils and has no rubbing parts in the vacuum, thus providing a contamination-free environment.

The present status is that all parts and subsystems for the electron beam pulser have been fabricated and final assembly is almost completed. Present activities are the electrical checkout of the energy storage capacitors and the calibration of the beam diagnostic sensors. After electrical checkout, the electron beam will be evaluated using a multisegment calorimeter to measure beam fluence uniformity. Annealing of 4-inch-diameter wafers and an overall pulser demonstration at the specification rate should occur in March.

Many subsystems, such as the electronic control system, vacuum system, and wafer transport system are operating successfully. The portion of the wafer transport/vacuum lock system associated with the electron beam pulser is operating as expected under microprocessor control. This wafer handling system has now demonstrated the movement of wafers in and out of vacuum, with no oils or grease at a track speed of 4.6 inches per second. This speed, using 4-inch wafers 2 inches apart, corresponds to processing rates of 1 wafer every 1.3 seconds. Vacuum cassette elevators are now being built which will bring the vacuum lock speed up to the track speed.

The ion implanter construction task is scheduled to begin in January. The ion implantation scheme will utilize the same transport system with the wafers moving horizontally under the beam at about 3 inches per second.

The entire junction processor system should demonstrate the implant and anneal of 500 4-inch wafers in 25 minutes before the end of 1981.

' 3/yk:<: If Jo Approval Signature Date

47

Contract Title:

Contract No. :

ENCAPSULATION TASK

SPRINGBORN LABORATORIES, INC. Enfield, Connecticut

INVESTIGATION OF TEST METHODS, MATERIAL PROPERTIES AND PROCESSES FOR SOLAR CELL ENCAPSULANTS

954527

This program involves the evaluation of materials and processes for the encapsulation of solar cells. Material selections are being investigated consistent with the DOE objectives of achieving a photovoltaic flat-plate module or concentrator array at a manufactured cost of $0.70 per peak watt ($70/sq. M) (1980 dollars).

During this quarter development efforts on solar module potting compounds were continued. An industrially ready version of EMA (ethylene methyl acrylate) was prepared and will be supplied by Springborn Laboratories in experimental quantities as a sheet lamination type of pottant. Experiments were continued with the butyl acrylate syrup intended for the liquid casting encapsulation technique. A wide range of cure formulations were developed, including a system capable of full cure in fifteen minutes at room temperature. The cured butyl acrylate resin has properties similar to the expensive silicones, but will become available at a much lower cost.

In order to insure maximum life of potting compounds and outer cover materials it is desirable to have an ultraviolet absorber that may be chemically coupled to the base resin to prevent extractfon. The synthesis of 5-vinyl tinuvin, developed at the Universi"ty of Massachusetts for this purpose, has been started at Spri'ngborn Laboratories in order to demonstrate commercial production feasi·bility.

A survey of edge seals and gasket compounds for the perimeter of the modules has been completed. All trial modules prepared in the future will employ a butyl compound sealant with a formulated EPDM gasket.

Evaluation of materials under RS/4 ultraviolet radiation is being continued. After 3,000 hours exposure the new EMA formulation shows no change in optical or mechanical properties. A new outer cover candidate, X-22417 acrylic film., has also survived this exposure with only slight decrease in tensile strength but no significant change in performance.

S/ Bernard Baum Approval Signature

48


I I I I I I I I I I I I

I I I I .1 I I

a '"·•.":··(··.·./' u

a

[] ..

u

a '

' .

In-House Program

ADVANCED PHOTOVOLTAICS TASK


(1) Advanced Materials and Device Characterization Laboratory Equipment presently in place includes: (1) automated data acquisition system for light and dark current-voltage characteristics, and spectral response; (2) transmittance and reflectance spectrophotometry; (3) high resolution profilometry; (4) ellipsometry; and (5) Hall and Van der Pauw for mobility and carrier concentration measurements. Presently under installation is a closed-cycle cryogenic set-up for temperature dependence studies of Hall effect and thermopower, and later, for photoluminescence measurements.

(2) CdS-Based Solar Cell Assessment Laboratory Experiments are planned to evaluate state-of-the-art materials and processes: (1) to determine which are best amenable to manufacturing with appropriate technology development (TD); (2) to identify critical scale-up problem areas for TD; and (3) to verify parameters that will be needed to determine the best approaches and to allow meaningful costing analysis. The chemical spray deposition technique for CdS films is the first approach to be investigated, because of its potential for simplicity, low cost, and minimum cadmium usage. A spray system with stainless steel or acrylic nozzles that can operate over large areas and in any chosen atmosphere is now operational. Provisions have been made for spraying the conducting tin oxide layer on the glass substrates (back wall structure), CdS films using aqueous solutions of CdC1 2 and thiourea, and wider band-gap films of Cd 1 Zn S by adding ZnC1 2 solution. Currently, the spray parameters suchxasxsolution molar concentration, flow rate, and substrate temperature are being optimized to obtain a baseline CdS film suitable for solar cell application. X-ray diffraction is used to determine average grain size and preferred orientation, while the conductivity, Hall mobility, and optical transmission properties are measured by conventional techniques. The surface morphology is observed with a scanning electron microscope and spatial distribution of impurities and elemental constituents of the films are measured by ion microscopy. Provisions for wet-dipping the CdS films, and later the Cd(Zn)S films, to form a heterojunction by converting the CdS to Cu 2 S are completed. Evaporation facilities for metallization and for "dry processing" the heterojunction are near completion.

R. J. Stirn JI.~ .. ~ Approv~ ~gnature

49

9 January 1981 Date

rt [j

n n

n u

0

In-House Program

PRODUCTION PROCESS AND EQUIPMENT AREA


Non-Mass Analyzed Ion Implantation

Several groups of silicon samples have been ion implanted directly with a phosphorous ion beam without mass analysis. The samples were thermally annealed, metallized and given an AR coating by Applied Solar Energy Corporation. The test results indicate that the solar cell made without mass analysis is as good as its mass analyzed counterpart. All of the samples used a standard metallization pattern which is optimized for a sheet resistance of 50 ohms/a. The best perfonning solar cells had a dose of about 1 x 1015 atoms/cm2 , which was the highest dose usm. This dose produced a sheet resistance of a bout 100 ohms /D . The mismatch in the sheet resistance to the metallization pattern resulted in a fill factor below 0.70 and an efficiency of about 13% (AMl). The tests indicate that the solar cell efficiency would increase to about 14% (AMl) when the dose is 2.5 (1015 ) atoms/cm2 • In addition, subsequent tests have shown that a diffused back surface field can increase the efficiency by a factor of 1.1.

The present plan is to test several gaseous sources beginning in 1981 for both front junctions and back surface fields.

Additional improvements have been incorporated into the modified Freeman Ion Source over the last period. An improved ion optics system has increased the beam current by a factor of 2. In addition, a new simpler hollow cathode design has eliminated the need for a cathode heater and has improved the starting speed. Tests are in progress to evaluate the performance with different gases.

Robotic Automation Studies

The Robotic and Teleoperator Group personnel have been involved in an automation evaluation study and in the development of a demonstration of computer vision applied to solar cell module assembly.

A strawman process sequence was developed for the purpose of evaluating automation potentials in the fabrication of solar cell modules. For each process step and each inter-process step, material handling requirements and sensing requirements for process control and quality control were identified. In addition, inter-process communications and buffering to insure a continuous assembly line flow in the case of asynchronous process steps and machine down time were considered.

Donald B. Bickler /Q1n (?~ Approval Signature

51

8 January 1981 Date

PRODUCTION PROCESS AND EQUIPMENT AREA IN-HOUSE SUMMARY (Continued)

The strawman process sequences were expanded to include the Solarex and Westinghouse MEPSDU sequences. A critique of each MEPSDU proposal relevant from an automation standpoint has been made. New strawman process sequences based on the MEPSDU proposals and incorporating automation strategies are being developed.

The Robotic and Teleoperator Group is also working on computer vision studies. The purpose of these studies is to demonstrate that robots with adequate sensing can perform successfully in the face of workplace uncertainties. The studies involve using computer vi~ion in module layup to determine cell locations, to verify cell emplacement, and to detect damaged or broken cells. Major pieces of software, which will be used in demonstrating computer vision, have been completed.

52

I I ll .


ITT lliJ

~ ,.

a I

..

PRODUCTION PROCESS AND EQUIPMENT

LOCKHEED MISSILES AND SPACE CO., INC. Sunnyvale, CA.

Contract Title: EVALUATION OF LASER ANNEALING FOR SOLAR CELL JUNCTION FORMATION


This suunnary covers work perfonned from September 1980 .to date.

The goal of the contract is to evaluate the merits of large spot size lase~ annealing of ion implantation induced-damage in Cz silicon wafers. A determination is also to be made of a laser system capable of single pulse annealing of 3-inch diameter or larger wafers, at a rate ~f 1 wafer per second.

Cell size scale-up from 2 x 2 cm sizes to 2 x 4 cm was achieved during this reporting period. For these larger cells, laser annealing was performed by a two-step overlap pulsed beam p~ocess. Various process conditions were used, including wafer surface variations, pulsed laser energy densities, with and without back ,surface fields fonned by both ion implantation and pulsed electron beam annealing, and screened and fired aluminum paste. Best results were attained with laser annealing at 1.5 J/cm.2 and the screened aluminum BSF configuration, where conversion efficiencies exceeding 15% AMl were realized.

A quantity of fifty (50) ion implanted three-inch diameter cells were fabricated by furnace annealing for reference. Cells were made with and without back surface fields. Those without BSF showed subpar conversion efficiencies which warranted repeating the fabrication of additional cells for confirmation. This repeat work is currently in progress.

The process verification phase of the contract was initiated for both small size cells as well as three (3) inches diameter. A laser energy density of 1.5 J/cm2 has been selected as the most suitable, along with screened and fired aluminum paste _for those requiring back surface fields.

Also during this period a high throughput laser system was conceptualized.

~..;.e-M. Lopez / 1/5/81

Approval Signature Date 53

Contract Title:

Contract No. :

Production Processes and Equipment

MBAssociates

San Ramon, CA

Automated Solar Module Assembly

955699

This contract is to produce prototype equipment for the totally automated assembly of solar modules using an industrial robot. The .assembly sequence starts with the completed solar cells and includes interconnecting the cells into a l'x4' string, encapsulating the string with glass, EVA and foil, and finally applying the edge seal and frame to form the finished module.

The program is broken into five parallel phases which were detailed in the previous PIM summary. Work since last September has concentrated on phases one and three.

Phase one involves improving the equipment developed under the previous contract to reduce the layup and interconnect time from 15 sec to 10 sec. This has been accomplished by rewriting the controlling computer program to overlap several operations. Time from cycle start to robot pickup connnand is now 8.5 sec, but that does not include robot pickup time.

Phase three is actually the bulk of the program as it involves the automated encapsulation of solar modules. To do this we are developing several distinct pieces of equipment.

Most complex is the Encapsulation Preparation Station. This machine measures and cuts to length, from roll storage, all the various encapsulation materials except the cover glass. It also guides the materials as they are laid up into the Automated Lamination Chamber.

Work to date has involved doing all of the detailed design work for the EPS. All major components have been received from ven4ors and construction has begun with the fabrication of the frame work and attachment of some components.

The Automated Lamination Chamber is a vacuum chamber with a built-in heat source to cure the encapsulants. It is of modular design in order to interface with the Encapsulation Preparation Station in a manner that would allow many chambers to be cycled simultaneously.

Detailed design work has begun on the chamber which includes a novel method of automatically covering and uncovering the chamber.

54

2 't Dec '80 Date

I I I I" I I

I I I I I I I I I I I I

n n 'ftl .• ::·::·.::·· u

D

fl u

D D n 0 rl u n lll

f1 u


MOTOROLA INC., SEMICONDUCTOR GROUP PHOENIX, ARIZONA

Contract Title: THE ESTABLISHMENT OF A PRODUCTION-READY MANUFACTURING PROCESS UTILIZING THIN SILICON SUBSTRATES FOR SOLAR CELLS.


Sunnnary of Progress for Period Starting September 1980.

This contract has been completed and the draft final report awaits approval for distribution.

/- ~ -J/ Ap I dL. prove ~~nature Date

55


MOTOROLA INC., SEMICONDUCTOR GROUP

PHOENIX, ARIZONA

Contract Title: PROCESSING EXPERIMENTS ON NON-CZOCHRALSKI SILICON SHEET

(MEPSDU SUPPORT CONTRACT)


Summary of Progress for Period Starting September 1980.

The JPL Low Cost Solar Array (LSA) Project, through the Phase I and Phase II efforts of the Automated Array Assembly Task, has sponsored the development of high volume, low cost process sequences suitable for production of commercial terrestrial silicon solar cells and photovoltaic modules. Much of this development work has been executed with single crystal Czochralski silicon wafers and substrates. Under the present contract, Motorola will further develop a low-cost process sequence for the manufacture of solar cells from non-Czochralski (non-Cz) silicon sheet forms, using Ribbon-to-Ribbon (RTR) substrates in particular, and other non-Cz material as available.

Particular development emphasis is being placed on material preparation, metallization, and solar cell production technology requirements which may be unique for non-Cz silicon sheet substrates. Where practical and desirable, processes presently available to the LSA Project for production of solar cells from single crystal silicon wafers are being adapted and utilized for the non-Cz substrates.

An additional task being undertaken is the evaluation of non-Cz process sequence cost effectiveness by using both a Motorola cost analysis program and the JPL SAMICS procedure. A comparison between the two costing techniques is being formulated.

, I '/ fl•, . / /L - /_.,r, '-·J "' \....- /- ~-rfl

Dote Approval sfgnature

56

I I I

I I I I I I

I I I I ,I I I I

0 '

'

n Li

fi LI

n Li

a r .

f1f u

0 ITT Li

0 }J

Il .

'

rl fJ

n

nl u

Contract Title:

Contract No:

PRODUCTION PROCESSES AND EQUIPMENT

Science Applications, Inc. 1710 Goodridge Drive, P.O. Box 1303

McLean, Virginia 22102

Analysis of Cost Effective Photovoltaic Panel Design Concepts Using Light Trapping

955787

The objectives of this contract were to summarize the results of prior .SAi work using light trapping in photovoltaic modules, and to begin exploration of the cost/benefit of these designs. Light trapping, a known but not well understood effect, can produce increased power levels (gain) on a cell due to the diffuse reflection and total internal reflection in the module encapsulant. Trapping makes use of regions between cells and achievable gain depends on the encapsulant layer thickness, its index of refraction, and the cell shape, size, and spacing in a complex way.

In-house SAi studies have evolved several novel ways to use trapping. Because there is no "classical" solution, a Monte-Carlo · computer model has been constructed to evaluate trapping. The model includes the effects of Fresnel reflection at all interfaces, optical extinction of light in the material, and diffusing material characteristics. The computer program can evaluate design options quickly and has been validated by experiments. Modeling has indicated that gains of 2.0 may be obtained for very sparsely packed arrays of cells and 1.2 to 1.4 for densely packed cells. The first task has summarized the Monte Carlo model in a series of design rules relating the physical, optical, mechanical and thermal properties of the module to gain. The rules allow a designer to get more power out of cells. This is particularly important for round cells.

The second task has evolved a procedure to optimize present day PV panel designs. Packing fraction (P.F.) is varied in conjunction with costs of solar cells, materials, construction, and land to calculate a gain. As cell costs and other costs change with time, optimum gain (or P.F.) will change. Therefore, based on the predicted solar cell costs ($/watt), it is possible to design "growth systems" that may prove to be advantageous to some users. When cell costs are high, as they are now, a low P.F. will provide greatest power out per invested dollar. As cell costs decrease, a retrofit with more tightly packed arrays of cells can be economical. For example, based on preliminary information 1979 panels should have used a P.F. of 0.16, 1982 panels-- 0.25, and 1986 panels--0.5. Solar cell costs will have to go below $0.50/Wp before P.F.'s above 0.5 appear interesting except in areas of high land costs, ($50,000 per acre and up). Growth systems will make greater use of current supplies of solar cells attract users interested in evaluating PV systems, and allow expansion of these systems as needs warrant. Many of the escalating cost items (land, structures, and labor) are procured early.

As a further result of SAi work, it was learned that thick optical films can be used to direct, channel and conduct light making possible completely new design approaches to photovoltaic modules. Three novel trapping approaches were studied, intercell trapping via a high index layer between cells, intracell trapping from the cell grid itself, and trapping of light passing through thin cells. Trapping produced in these and customary designs were reviewed and results indicate that trapping methods have merit in PV modules to improve performance, and to allow less tightly packed and thinner cells to be used.

T~~ T. M. Knasel 6 January 1981


57

Contract Title:

Contract No. :


Solarex Corporation

Rockville, Maryland

Phase II of the Array Automated Assembly Task for the

Low Cost Silicon Solar Array Project

954854

This program has been completed. Studies were conducted on several fundamental aspects of electroless nickel/solder metallization for silicon solar cells. A process proposed by Motorola, which precedes the electroless nickel plating with several steps of palladium plating and heat treatment, was compared directly with single step electroless nickel plating.

It was demonstrated by ellipsometry measurements that the electroless nickel plating solution dissolves silicon dioxide. Measurements of tab pull strengths and electrical characteristics of cells show that the presence of the oxide has no effect on cell properties. It was also shown, by sheet resistance measurements and gravimetric measurements, that the plating solution dissolves some silicon before depositing nickel. This phenomenon dictates that special care be taken during the diffusion process to assure that the p-n junction is deep enough to survive the silicon dissolution.

Brief sintering at relatively low temperatures after nickel plating sometimes increases otherwise poor adhesion. It has been shown by leakage current and electron microprobe measurements that sintering can safely be conducted for long times at 3QOoc, but it has also been shown that excellent adhesion can be obtained without sintering.

Cells with electroless nickel/solder metallization have been shown to survive perfectly for over 1,000 hours under bias-temperature-humidity stresses of 0.45 volt forward bias at 95°c and 85% relative humidity. This metallization also survives 763 hours at 1000c and 25 cycles of thermal shock from -40° to +100°c.

The Motorola process was found to be extremely lengthy and cumbersome, and was also found to produce a product virtually identical to that produced by single step electroless nickel plating, as shown by adhesion tests and electrical characteristics of cells under illumination.

1 /s/81 Approval Signature Date

58

I I -I Ii II

I I I I I I I .

I I I I I I I I

[J . .

n

fff u n ll!

n u

Il . .

n lJ

0 I

.

n u

u I . .

Vi u

Contract Tit I e :

Contract No. :


Solarex Corporation

Rockville, Maryland 20850

A MODULE EXPERIMENTAL PROCESS SYSTEM

DEVELOPMENT UNIT (MEPSDU)

955902

The purpose of this program is to demonstrate the technical readiness of a cost-effective process sequence that has the potential for the production of flat plate photovoltaic modules which met the price goal in 1986 of 70¢ or less per Watt peak. For this demonstration Solarex will:

Design a detailed cost-effective process sequence, Design the equipment required for each process station, Fabricate and assemble the designed MEPSDU (process station equipment). Perform technical readiness demonstration runs resulting in the production of tested modules and the gathering of sufficient production data to permit validation of the program goal, Prepare a process instruction manual including in-line process control information, Perform an economic analysis of the elements of the MEPSDU which includes consideration of performance, production rate, maintenance, process monitoring and control and the sensitivity to different types of input material.

During this initial period (starting December 1, 1980), the program efforts have included preparation and submission of the Work Breakdown Structure, the Baseline Cost Estimate and the Program Plan. A review of the proposed process sequence is underway with laboratory verifications underway. The preliminary process includes the following features:

Semicrystalline silicon (10cm X 10cm) as the silicon input material. Spray-on dopant diffusion source~ Al paste BSF formation. Spray-on AR coating. Electroless Ni plate-solder dip Metallization. Laser scribe edges • K & Stabbing and stringing machine. Laminated EVA modules.

This process will be reviewed and assessed for technical and economic feasibility in the next two months and a process selected for presentation to JPL in the Preliminary Design Review scheduled in March, 1981.

59

January s, 1981 Dote

Contract Title:

Contract No. :

PRODUCTION PROCESS & EQUIPMENT AREA

Spectrolab, Inc.

Sylmar, California

High Resolution, Low Cost Solar Cell Contact Development

955725

The scope of this contract covers the development and evaluation of forming solar cell collector grid contacts by the MIDFILMR process. This is a proprietary process developed by the Ferro Corporation which is a subcontractor for the program.

The MIDFILM process attains line resolution characteristics of photoresist methods with processing related to screen printing. The surface to be processed is first coated with a thin layer of photoresist material. Upon exposure to ultraviolet light through a suitable mask, the resist in the non-pattern area cross-links and becomes hard. The unexposed pattern areas remain tacky. The conductor material is applied in the form of a dry mixture of metal and frit particles which adhere to the tacky pattern area. The assemblage is then fired to ash the photo-polymer and sinter the fritted conductor powder.

Cells have been evaluated using different resins, powders, and firing schedules. An optimum resin and powder have been selected. An optimized firing process has been developed which consists of a pre-fire to remove organics, followed by a higher temperature firing which sinters the powder into a conductive ohmic contact.

Work is continuing on the evaluation of powders forming contact of alternate materials such as copper and molybdenum.

Date

I I .

I " I I I I I I I . I I I I I I I I I

0 l .

ll a a a D '

.

~ I I

n n 1Jl

f:1{\ lf

0 . .

Contract Tit I e :

Contract No. :


University of Pennsylvania Philadelphia, PA

Analysis and Evaluation of Processes and Equipment

JPL-954796

The analysis of the front metallization design on the solar cell performance for large area solar cells has led to a set of definitive Design Rules, most of which were included in the 16th Project Integration Meeting Summary Report. The Design Rules have been augmented by the following: · * If the bus lines cannot have sheet resistance small compared to the

grid lines, omit the bus lines, and use a connector to the grid lines.

* For square bus wires of height-to-width ratio k, multiply each n in the previously published design rules by 4k/n.

*Forbus lines of constant sheet resistance Rsh,BL' rather than thickness directly proportional to width as in round or rectangular wires, the relationship

TBL - ( I~ ) ~ 2W - L1 3 vmp Rsh,BL0 BL

applies. o is a shape factor depending on bus geometry, and varies between 0.75 and 1.0.

* Arrange grid lines normal to bus lines, and parallel to each other.

While in general an optimum value exists only for the grid line and bus line shading ratios, with monotonously decreasing losses found for grid and bus line spacing tending towards zero (with the shading ratios maintained at their optimum values), this rule does not hold, when the bus line is a round or rectangular wire, or the choice of grid line width is limited by technological requirements. In these cases, optimum values can be found for the bus line spacing and wire diameter separately, or for the grid line spacing in dependence on the minimum practical line width.

Some of the metallization processes used in solar cell production are not capable of yielding low losses. Worst seem to be the print-on thick film processes, which are limited to line widths or 127 µm or greater, and which yield onlya fraction of the bulk conductance of the deposited metal.

M. Wolf Approval Signature

61

6 January 1981 Date

PRODUCTION PROCESS AND EgUIPMENT

Westinghouse Electric Corporation Pittsburgh, PA 15235

Contract Title: SILICON DENDRITIC WEB MATERIAL PROCESS DEVELOPMENT


A total of 12 meters of dendritic web has been delivered to JPL under this contract. The web was delivered in lengths that were multiples of 10 cm. Each piece was sufficiently wide to produce 2 cm wide cells.

A total of 133 cells of dimension 2 x 10 cm have been fabricated on dendritic web silicon following the process sequence discussed previously. The process monitors used to achieve uniform cell characteristics will be discussed. The average efficiency of these cells was 12.4% with a maximum efficiency of 14.2%.

These cells were interconnected using ultrasonic seam bonding. Since previous tests indicated that reproducible ultrasonic bonds could not be made to the At eutectic on the back surface of the cell, a back contact metal of evaporated TiPdAg and electroplated Cu was applied.

A demonstration module, 30 cm by 60 cm was fabricated using ethylene vinyl acetate lamination. Module properties will be discussed.

62

I I I ,. I I I I I I .

. I I I I I I I I I

111 h~

n

a r I I

a Flt Li

n

n . I

0 -

0 fl Wt

u \ .

u


WESTINGHOUSE ADVANCED ENERGY SYSTEMS DIVISION

PITTSBURGH, PENNSYLVANIA 15236

Contract Title: A MODULE EXPERIMENTAL PROCESS SYSTEM DEVELOPMENT UNIT (WESTINGHOUSE)


The object of this contract is to design, develop, fabricate and operate a Module Experimental Process System Development Unit (MEPSDU) which will produce photovoltaic modules using a cost-effective process sequence. The process sequence utilized will be optimized to demonstrate that modules can be produced at the 1986 cost goals.

Work on the contract was initiated on November 26, 1980 and the period of performance is 26 months.

A preliminary process sequence has been defined using dendritic web silicon sheet material. Since dendritic web is most easily (and economically) processed in long lengths, several steps in the process sequence were developed specifically for dendritic web sheet material. The process sequence involves fourteen individual process stations, defined as follows:

• • • • • • • • • •

Pre-diffusion cleaning Front and back junction formation Oxide etch Anti-reflection coating application Photoresist coating application Grid pattern definition Metallization Metal rejection and plating Cell separation Cell test

• Cell interconnection • Module lamination • Module test • Module packaging

A SAMICS cost analysis of the Westinghouse MEPSDU process sequence indicates that in a high volume, automated manufacturing facility, the cost goals can be attained. In addition, SAMICS analyses have been carried out to study the sensitivity of overall cost to variations in capital expenditures, module efficiency, dendritic web width, and process yield.

Current emphasis on the program is directed toward completing preliminary module design and MEPSDU process sequence design. The preliminary design review meeting is scheduled for late February, 1981.

C 12-23-80 .r,,....., ' ' \ Approval Signature Date

63

n ITT1 t~

n I I

a n

ITT u

a I

'

0 n lLl

fl y

I] en u ITT u n u

u I

..

a

ENGINEERING AREA

JET PROPULSION LABORATORY


In-House Program

Array Requirements

The dra~ Safety Standard for Photovoltaic Modules and Panels submitted by UL was reviewed by Engineering Area personnel. Sections of the dra~ dealing specifically with construction requirements (document 5101-164) will be included as part of the Block V procurement package for both ILC and Residential Modules. In addition, a safety workshop has been organized in conjunction with this 17th PIM to be jointly conducted by LSA Engineering and Underwriters Laboratories. The workshop will specifically address features of the draft UL Safety Standard for Photovoltaic Modules and Panels.

Also in support of the development of module safety requirements, JPL has recently completed an assessment of requirements concerning the ability of the capacitance of a photovoltaic module holding a hazardous charge following extraction of the module from a high voltage array. Results to be presented in the workshop indicate permissible capacitance levels from cell string to module ground. Current modules easily meet the requirements.

Array Subsystem Development

A design data package describing the large ground mounted array displayed at the last (16th) PIM was completed including detailed panel and array structure design drawings. JPL Drawing Nos. 10097880, 10097881, and 10097882 provide sufficient detail to permit adaptation to a variety of module configurations. Copies are available from the LSA Engineering Area. A task report documenting the overall structure design effort is currently in preparation.

Array Component Engineering

The module soiling studies task report was published and distributed during this reporting period. The report, 5101-131 (DOE/JPL 1012-41) "Photovoltaic Module Soiling Studies May 1978-0ctober 1980", November 1, 1980, describes the results to date of the in-house experimental study to characterize and understand the effects of outdoor contaminants on sensitive optical surfaces of flat-plate photovoltaic DX>dules and cover materials. This report is available through the LSA Data Center and NTIS.

Approval Signature

65

ENGINEERING AREA IN-HOUSE SUMMARY (Continued)

During this reporting period, the series-parallel effort concentrated on the development of a hot-spot qualification test and, in turn, a better understanding of the operation of cells under back-bias conditions. Several problems in connection with the analytical prediction of hot-spot problems and subsequent correlation of these results with tests are under investigation. These include the significance of power dissipation in a cell relative to the cell area, uniformity of power generation loci, and the uniformity of the light beam over the surface of the cell under test. The infrared camera equipment is being used to determine the temperature gradients over the surface of test cells. A hot-spot qualification test has been included in the Block V procurement package and test results will be presented at this PIM.

As part of the electrical isolation study, backcover material supplied by one of the Block IV manufacturers was tested to breakdown. This material is Tedlar-Aluminum-Tedlar (.0015 in. - .002 in. - .0015 in.). It was found that under grounded foil conditions, the 50% probability failure voltage is 7.3 kV while under floating foil conditions, the 50% probability failure voltage is 14.6kV (stress= 4.9 kV/mil, both cases).

DuPont has sent to JPL two rolls of 4-mil "experimental" Tedlar for voltage breakdown testing. Testing will begin when Sheldahl delivers their composite Mylar and Tedlar films and the automated Low Voltage Breakdown Apparatus is completed.

Having established voltage breakdown properties of insulating films by flaw characterization, the same is now being attempted for cell string systems. A fixture is being designed to house an interchangeable two-cell/interconnect electrode system which will be used to break down various sized air gaps with and without insulating films. From such testing, we can determine the deviation from parallel plate breakdown and hence ascertain the effects of cell string defects.

The solar cell fracture mechanics effort continued during this reporting period. Optical microscopy and SEM examination of solar cells from Applied Solar Energy Corp. which were facture mechanics tested indicated that the fracture initiating flaw for these solar cells are edge chips and cracks, some of which were not observed prior to the fracture testing. These cracks were sometimes covered by metallization and A/R coating and were not obvious to see. A quantitative correlation of fracture strength and the flaw size is underway.

A task report (5101-163) "Determining Terrestrial Solar Cell Reliability", which documents the proceedings of the solar cell reliability workshop held May 1-2, 1980 at Clemson University, Clemson, South Carolina was published during this reporting period. Included in the report are reproductions of graphic presentation materials and highlights of discussions related to solar cell reliability test methods. The report is available from the Data Center.

66

I I I .

I I 11

I I I I I

' I I I I !I I I I

a '" LI

n a D '

I .

0 Mil u

D

n n u

D ' .

n I

'

n u

u

ENGINEERING AREA IN-HOUSE SUMMARY (Continued)

In the area of environmental test development evaluation of the use of a "greenhouse" effect accelerated aging environmental exposure technique is continuing. After 75 days of exposure mini-modules from the outdoor hot box test have been taken down, inspected, flashed and voltage breakdown tests run. There has been some cosmetic degradation to several of the modules, but no electrical degradation to any of the modules. The post-exposure voltage breakdown test results are being studied. The modules are back in the hot box for further exposure.

A major effort looking at the mechanical fatigue life of cell interconnects is also continuing. The predicitve model presented at the last PIM correlated well with interconncect failures experienced at Schuchuli. Applying this failure prediction technique to similar modules at the Mead NB site indicates that interconnect fatigue problems should be expected there within two years. During the reporting period, an interconnect fatigue cycling apparatus was fabricated and large numbers of interconnects tested to failure. An expanded predictive module based on observed probabalistic failure statistics together with the test data will be presented at this PIM.

In the area of PY/Thermal module development, tests were completed on an unglazed PV/T module configuration to verify the feasiblity of a PV/T test method proposed as part of the !PC. Preliminary indications are that the test method will be applicable to a variety of collector types and configurations. Work has been initiated on a joint task report with Arizona State University to document the background and rationale for the electrical and thermal performance test methods being developed for flat-plate PV/T's and concentrator modules.

Performance Criteria and Standards

The Array Subsystem Task Group met in Huntsville, AL on November 19 and 20, 1980. The Electrical Performance Subgroup of the Array Subsystem Task Group met in October and November, 1980. Test methods for actively and passively cooled concentrator modules were reviewed. Principal issues were: (1) the appropriateness of using reference cells for the I-V characterization of concentrator modules; (2) the advantages and disadvantages of several different formats for presenting electrical and thermal performance data.

The PV/Thermal Subgroup of the Array Subsystem task group met in Huntsville on November 18, 1980 at Wyle Laboratories. The subgroup discussed a draft of the Operating Cell Temperature Determination Test for Flat Plate Actively Cooled Modules and several performance criteria statements. A final version of the test method was prepared for the Task Group. Several of the criteria statements were also prepared for final review by the Task Group.

In support of the SERI funded JPL standards efforts, Wyle Laboratories was contracted by JPL to identify and document corrosion sensitivities and failures associated with outdoor exposure of photovoltaic modules and components and to document performance criteria and candidate test methods for inclusion in IPC-2. A data package on the corrosion observations at JPL field site prepared by LSA Quality Assurance was delivered to Wyle.

67

ENGINEERING TASK

AIA Research Corporatio~

Washington, DC

Contract Title: INTEGRATED RESIDENTIAL PHOTOVOLTAIC ARRAY DEVELOPMENT


The objective of this study is to develop optimal roof mounted arrays for residences that require the least life cycle energy cost. Development of an optimal array will follow an integrated systems approach that considers detailed electrical, mechanical and environmental requirements, as well as such regional variations as codes, construction practices and local costs. The resulting array design will be fabricated in a prototype model to identify additional roof-array interface concerns in production, manufacturing, installation or maintenance.

The study methodology is intended to develop the broadest range of conceptual designs from architects, engineers, homebuilders and designers representative of the Northeast, Southeast and Southwest regions. Eight teams representing a cross section of new and retrofit construction activities will be chosen by an advisory panel convened by the AIA/RC. Its representatives include architects, engineers, homebuilders and manufacturers.

Each team will develop conceptual designs for two generic integrated arrays following a design workshop held at the AIA/RC. During the design process each team will have available technical support provided by the advisory panel. Upon completion these concepts will be independently evaluated for design optimization opportunities. The best concept will be further developed in detail by its design team and appropriate design trade-offs evaluated by the advisory panel for the effect of mass production. A prototype of the final optimized design will be fabricated for final evaluation by the advisory panel prior to shipment to JPL.

The current status of the study shows that proposals have been received from a broad cross section of design teams in each market region. These proposals will be reviewed and teams selected during the next period by the advisory panel. The Design Workshop to be held in the next period will cover the following areas of integrated design: roof construction; life cycle cost; wiring harnesses; codes and standards; safety; module manufacturing;and current field experience.

George Royal Project Manager 68

1/5/81

Date

I I -

I -

I I I I . .

I I I I I I I I

fi u nl u

D

n lhl

r1 u

u a

Contract Tit I e :

Contract No. :

ENGINEERING AREA

BURT HILL KOSAR RITTELMANN ASSOCIATES BUTLER, PENNSYLVANIA

COMMERCIAL/INDUSTRIAL PHOTOVOLTAIC MODULE AND ARRAY REQUIREMENT STUDY

955698

Sunmary of Progress from September, 1980 to February, 1981. The objective of this study was to determine the design requirements imposed on the photovoltaic module, panel and array by conmercial/industrial buildings and the building industry in general. In order to accomplish this, a review of the model building codes, referenced standards and studies of pertinent aspects of commercial/industrial features that relate to photovoltaic module and array design was perfonned. In addition, example installation mountings were defined and costs generated in order to determine cost drivers. The final report is anticipated to be available sometime during the early part of the summer of 1981.

Several important conclusions have been reached as a result of this study:

1. The commercial/industrial sector does not utilize standard building modules. This implies that the size and shape of a photovoltaic module and panel will be defined from an electrical and/or shipping handling standpoint.

2. The codes can be very restrictive to the use of certain materials such as plastics. It is important that the manufacturers know the limitations of area and location regarding such materials.

3. As the National Electrical Code now stands, wiring in certain commercial/industrial applications could be extremely costly and special conditions such as the use of conduit may neet to be met. Presently, a draft of an NEC article dealing specifically with photovoltaics is being generated and hopefully will eliminate this potential problem.

4. The photovoltaic manufacturers should design a photovoltaic module and panel whose ancillary functions (i.e., roof covering, veneer, spandrel panel, etc.) offers the path of least resistance in the building regulatory process. This will help to insure the fastest and least costly product approval process. As the program develops and the product is accepted by the building industry and the buying public, the functions can become more and varied.

/ ASate

69

ENGINEERING AREA

Carnegir-Mellon University Pittsburgh, PA

Contract Title: Exploratory Study on Safety and Product Liability Considerations for Photovoltaic Modules/Arrays


The objective of this study is to conduct an exploratory study and provide explicit considerations and recommendations relative to product safety on future solar photovoltaic module/array device designs. This study is confined to flat-plate photovoltaic modules of the types presently being developed by the Low-Cost Solar Array (LSA) Project.

In performance of this study Carnegie-Mellon University has performed a survey (limited, selective) of photovoltaic module manufacturers' to obtain first hand information on factors of safety that are built into modules during production. The study deliverables include development of a "strawman 11 safety design procedures, which includes, but not necessarily is limited to, the following:

(a) Fault-Tree Analysis Methodology

(b) Failure Modes and Effects Analytis (FMEA)

(c) Ranking of hazards, by probability of occurrence and severity/importance.

It has been concluded that development of appropriate safety and product liability guidelines by the photovoltaic_connnunity should be initiated now - prior to conunercialization. Safety and product liability factors can be introduced as a part of design risk-benefit analyses and product standards.

With regard to the newly developing photovoltaic industry there are concerns relative to litigations which might result if injury is caused by a defective product. A product can be interpreted to be defective.if there can be shown to be excessive preventable danger. Of the various legal theories upon which action might be based, three are included in the study, i.e., negligence, breach of warranty and strict liability.

STATUS: The initial report on this effort is scheduled for early 1981 with a follow-up report planned for later in the same calendar year.

A. Weinstein 01/08/81


70

I I

I I I I I I I I I I I I I I I

n rJ I I fi '1Jl

a []

a a ITT u

a fl a '

.

n 0 till u

a

u

Contract Title:

Contract No. :

ENGINEERING AREA

Clemson University

Clemson, SC 29631

INVESTIGATION OF RELIABILITY ATTRIBUTES AND ACCELERATED STRESS FACTORS ON TERRESTRIAL SOLAR CELLS

954929

The objective of this study is to develop test methods for evaluation of solar cells, perform investigations of factors involved in the reliability of terrestrial solar cells and develop specifications for the accelerated stress testing of solar cells. The overall program approach involves determining the reliability characteristics of currently available connnercial cells by accelerated stress testing. The third year's effort also entails studying methods of second-quadrant characterization, and some experimental work aimed at modeling these effects.

A method of quantifying the loss of antireflective coating has been developed using an IBM 7400 spectrophotometer system. When cells are subjected to pressure cooker accelerated testing (121°C, 15 Psig steam) they loose their A-R coating and use of the IBM 7400 has shown the correlation between A-R coating loss and power output degredation.

Routine first quadrant accelerated stress testing is continuing on a total of 12 different cell types.

Date

71

ENGINEERING AREA

DSET LABORATORIES, INC.

PHOENIX, ARIZONA 85029

Contract Title: SUNLIGHT AGING TESTS OF SOLAR CELL MODULES

Contract No.: BQ 713131

The accelerated aging of mini-modules was continued using DSET's Super-Maq@ Fresnel-concentrating accelerated weathering machine. Through December 31, 1980, the six Block III modules have been subjected to 1,639,410 langleys of radiation. The Block III modules have been exposed to an equivalent of 8.5 years of outdoor weathering in an "average" southwestern environment.

Three new mini-modules, exposed on the Super-Mag® since October 10, 1980, have been subjected to 276,870 langleys of radiation as of December 31, 1980.

The two Block II modules were removed from the Super-Maq® after having been subjected to 2,780,400 langleys of radiation. The modules have been returned to JPL for failure analysis.

Twenty-four submini-modules were placed on exposure on September 10, 1980. Eight of the modules are being exposed on a standard EMMAQUA® accelerated weathering machine, eight on an equatorial mount with water spray (EEKQUA), and eight on a 34° South direct exposure rack.

Weekly visual inspection, monthly 35mm slide photos, and monthly I-V measurements are used in monitoring the physical and electrical characteristics of the modules. Failure modes such as cell cracking, delamination, carbonation, and contact corrosion, as well as max power losses, non-ohmic contact, and series resistance changes have been observed during the Super-Maq@ exposure program.

.... ~~-~µJl.,u-Approval Signature

72


I I I .

I II ti

I I I I .

I I I I I I I I I I

n n [l

a a a a n a ro

0 D 0 0 a 0

fl u

u

ENGINEERING AREA General Electric Co.

Advanced Energy Programs Department Philadelphia, PA 19101

Contract Title: Integrated Residential Photovoltaic Array Development

Contract No. : JPL 955894

The objective of this contract is to develop an optimized integrated residential photovoltaic array concept and to prepare detailed design definition which includes sufficient information to permit fabrication, assembly and installation by a competent third-party. A prototypical simulated roof section of the optimized design concept will be constructed to demonstrate the fabrication and installation features of the photovoltaic array.

This contract effort was initiated on October 24, 1980. The first task activity, which is underway at this time, involves the selection of three generic residential array concepts. This selection process began with the formulation of a set of evaluation criteria. A comprehensive list of existing and proposed residential array designs was developed and each design was rated against the established criteria to select the three most promising concepts for further design optimization which includes the evaluation of the various factors involved in the determination of the total array installed cost.

Based on the results of this optimization study one preferred design concept will be selected for further detailed design development and costing analysis. A representative roof section of this selected photovoltaic array design will be constructed to illustrate the various aspects of the installation including module producibility, interfaces with the roof structure, mechanical attachments, electrical interconnections, module removal and replacement, and maintenance procedures.

1....s_ ~ ~lr-J,J', Approval Signature Date

73

ENGINEERING AREA IIT Research Institute

Chicago, I1

Contract Title: Development of Elements of a Reliability Enginnering Design Guidebook for Flat Plate Photovoltaic Modules/Arrays


The objective of the IITRI support study is to provide and/or develop engineering-oriented reliability data, guidelines, procedures and techniques to serve as elements of a rel i abi 1 i ty design gu·i de book on terrestrial, low-cost, photovoltaic (PV) modules/arrays. The approach being used in this support study is to first initiate an on-going reliability engineering data base and then develop and validate for use, reliability design guidelines based on information derived from that data base. The intent is to provide well founded validated design guidelines that can be used by the photovoltaic industry to build reliability into their products most cost effectively.

Meeting the objective involves accomplishment of at least the following sub-tasks:

o Formulate guidelines for appropriate reliability analysis methodologies {for example, reliability allocation generation and validation, etc.)

o Develop methods to establish failure rates for PV modules.

o Develop methods to determine and assign failure rate and degradation modifying factors and formulate an analysis tool for assessing the reliability/life potential of photovoltaic modules.

Included in the sub-tasks are the performance of qualitative and quantitative analysis as well as complete validation of the guidelines and analysis methods.

P. Milhalkanin/R. Anderson 01/08/81 Approval Signature Date

74

I I ,

I I I I I I I I I I I I I I I I I

n n

a n LI

a a .

0 0

a n u

u

In-House Program

OPERATIONS AREA

JPL


All prototype Block IV modules for test have been received at JPL except the ARCO Solar residential design. Modules from General Electric, Motorola, ASEC, and Spire have satisfactorily completed the qualification test program. Solar Power has terminated developmental activities on the Block IV steel substrate design. ARCO Solar (intermediate load), Photowatt, and Solarex modules are in the qualification test cycle. Small production contracts have been awarded to General Electric, Motorola, ASEC, Solarex, and Spire. Motorola has initiated deliveries on their contract.

Qualification testing of four commercial module types for the United Nations Developmental Project (Halcrow/World Bank) on agricultural pumping has been completed. Two domestic and two foreign module types were tested. Results will be reported at this integration meeting.

Environmental testing of commercially available Cadmium Sulfide modules and of sample modules for the MIT/LL Northeast Residential Experiment Station has been initiated.

Failure analysis on cell string shorts-to-grounq on metal-backed modules from Natural Bridges National Monument has been completed. Most of the problems derived from interconnect foil shorting to the bezel. Failure analysis of interconnect fractures on modules from Schuchuli, Upper Volta, and Mount Laguna confirms a plastic fatigue mechanism at work. Time to failure is affected by the nature of the strain relief loop used in the module, which varied somewhat in the production run for this design type.

I /e, I BI I Date

75

LARGE-SCALE PRODUCTION TASK

ARCO Solar, Inc.

Chatsworth, CA

Contract Title: Design, Fabrication, Test, Qualification, and Price Analysis of "Third Generation" Design Solar Cell Modules


This contract involves two module designs, one for intermediate load and one for residential rooftop applications.

Configurations are as follows:

ILM Dimensions ll.9i" x 47.94"

(0.3025m x 1.218m)

Structural elements Water-white temperedglass superstrate, extruded aluminum frame, junction box

Cells 35 4.05" Cz singlecrystal, in series string, redundant interconnects

Laminate Glass/PVB/cells/PVB/ grounded Tedlar/steel/ Tedlar back foil

Nominal power output 37W@ 28°C

RESIDENTIAL 22.97" X 47.24" (0.583m x 1.200m)

Charcoal· gray, Tedlar coated galvanized steel pan, in standard batten-seam roof style

60 4.05" Cz singlecrystal, in 3 parallel strings of twenty in series, redundant interconnects

Tedlar/EVA/cells/EVA/ Tedlar/galvanized steel

60W@ 28°C

ARCO Solar has fabricated 29 intermediate-load modules, 20 delivered to JPL for qualification and testing, nine undergoing qualification testing at ARCO Solar. A status review with JPL of the rooftopmodule effort was completed in December 1979 and the documentation package for production of modules has been completed.

1-1-?I Date

76


n n

fl a a ITT &J

0 Fil l8

f\1 u

n LI

n u

u '

.

Contract Title:

Contract No. :

LARGE SCALE PRODUCTION


BLOCK V PRODUCTION MODULES

720307

Sunnnary of Progress for Period Starting September 1980.

Shipments of Block V qualified modules against this contract began in December 1980 and are expected to continue through February 1981.

l~-8'i


77



Contract Title: DESIGN, FABRICATION, TEST, QUALIFICATION AND PRICE ANALYSIS OF "THIRD GENERATION" DESIGN SOLAR CELL MODULES


Sunnnary of Progress for Period Starting September 1980. Module qualification testing has been satisfactorily completed at JPL and all documentation and contractual requirements have been satisfied. No additional effort will be expended on this contract.

/-6-81 Approval Signature Date

78

I I I ,


a

Contract Title:

Contract No. :

MODULE PRODUCTION TASK

PHOTON POWER EL Paso, Texas

Letter of Agreement

LK-720306

This paper is a simple update of our last report.

In the research area, we have achieved 8.15 percent cell efficiency in 1980.

In the development activities, we have been able to make 3-5 n/Dtin oxide films.with satisfactory transmission (68% air/air), and spray at 2-1/2 times the previous rate in Cadmium Filming.

The factory is now in the process of being conunissioned with the glass washing and tin oxide filming sections fully operational. Work continues on the Cadmium Sulfide section of the line.

An encapsulant has been found for the back of our panels which seem satisfactory from the humidity, and thermal cycling tests.

The 1981 projections are for production of 750 KW+ 250 KW if all goes well.

G. A. Roderick 01/09/81


79

LARGE SCALE PRODUCTION TASK

PHOTOWATT INTERNATIONAL, INC., (SENSOR TECHNOLOGY, INC.) TEMPE, AZ 85281

Contract Title: THIRD GENERATION SOLAR CELL MODULE

Contract No. : 955410 Date: January 5, 1981

This contract was initiated November 1, 1979 and has as major objectives the design, fabrication, performance qualification and price analysis of an intermediate load solar module that meets or exceeds the requirements of JPL 5101-16. Photowatt's objective is also to design into the intermediate load module, a significant degree of producibility and tolerance to normal production related defects.

The initial design and subsequent design review have been completed. Prototype modules have been fabricated and delivered to JPL. Project personnel have performed characterization of these modules and initiated qualification testing. The initial SAMICS/SAMIS pricing analysis has been completed.

During the next quarter, revisions in the engineering, manufacturing, and quality control documents will be completed in preparation for the final design review.

Michael C. Keeling Approval Signature

80

Jan. 5, 1981 Date


n f1l u

a a a flt la

n I '

0

0 I .

fl u

u (]

SES, Incorporated

Newark, Delaware

Contract Title: Exchange of Information

Contract No. : LK-694034-01

There have been no substantial changes in the design or performance of the standard SES, Incorporated product since the last report. Present efforts are directed at increasing the rate of production in order to meet shipment needs.

Presently specified module efficiency is 3 to 4% for commercial product.

Panels for nominal 12 volt operation are fabricated with extruded aluminum support structures from 48 series cells i2 individugl modules. The nominal peak power rating (100 mw/cm, AMD, 28 C) for these panels is 65 watts (4.1 amps@ 16.0V). Panel size is 3~" X 103".

Super Cell-Internal Circuit (Rear View) r-Wire Grid--,

0 Positive Copper Bus

Positive Terminal 8

Negative Terminal

(/Approvals'ign~ Robert O. Johnson

0

Continuous Sheet Negative Electrode

Positive Copper Bus

L_wire Grid__j

Negative Terminal

Positive Terminal

Rear View of 7.8" square cell

81

Contract Title:

Contract No. :


Solarex Corporation

Rockville, Maryland

Design, Fabrication, Test, Qualification and Price

Analysis of "Third Generation" Design Solar Cell Modules

955404

Solarex has built 36 modules, 18 for intermediate load center application and 18 for residential applications. Features include:

Semicrystalline silicon as the basic cell material.

Outside envelope dimensions of 63.5 cm x 120 cm.

72 9.5 cm x 9.5 cm cells arranged in a high density pattern.

Fault tolerant cell-interconnect design which allows for some cell damage with little resulting performance degradation.

3/16" tempered Sunadex Superstrate Ethylene Vinyl Acetate (EVA) Pottant, White Tedlar moisture barrier.

Manufacturing is complete. Environmental testing of ten modules at Solarex is complete and the modules forwarded to JPL. Environmental tests are being completed at JPL. The final design review is scheduled for January 15, 1981.

__ \~~ \Us.k-Approval Signature

82

January 5, 1981

Date

I I I ,


11

u

a a ' '

.

~ tn

fir ~

n u n u

~ ' .

a t .

0 I

..

n u

Contract Title:

Contract No.:

LARGE-SCALE PRODUCTION

SOLAR POWER CORPORATION

WOBURN, MASSACHUSETTS 01801

MODULE FABRICATION AND TEST

BD-730103

The purpose of this contract is for Solar Power Corporation to fabricate a quantity of new generation modules (product number LG12-361G) and deliver these to JPL for the purpose of Qualification testing per JPL Doc. 5101-16 Rev. A.

The modules will include state of the art materials and construction techniques and are scheduled for delivery early in January 1981.

Approval Signature

83


Spire Corporation Bedford, Massachusetts 01730

Contract Title: DESIGN, FABRICATION, TEST, QUALIFICATION AND PRICE ANALYSIS OF THIRD GENERATION DESIGN SOLAR CELL MODULES

Contract No.: LK-730100

The Block IV module has been revised to accommodate a larger solar cell. The new design uses 108 cells to obtain similar performance to that generated from 1.52 cel1s previously. The parallel crosstie frequency has been changed to reduce the maximum power dissipation per cell in the event of reverse bias operation.

The design is completed and cel1s are in proce;s. Forty modules will be fabricated, producing a peak power of 2 kW.

~proval Signature

84


n n LSA PROJECT ACTIVE CONTRACTS

n EXPECTED START COMPLETION CONTRACT TASK

NAME DATE DATE NUMBER DESCRIPTION

a SILICON MATERIAL TASK:

D AEROCHEM RESEARCH LABORATORY 10/79 02/81 955491 SILICON HALIDE--ALKALI METAL

PRINCETOtl, N.J. FLAMES

BATTELLE MEMORIAL INSTITUTE 10/75 11 /80 954339 EVALUATION OF Si PRODUCTION COLUMBUS, OH

a ENERGY MATERIALS CORP. 04/79 10/80 955269 GASEOUS MELT RFPLENISHMF.NT . HARVARD, MA SYSTEM

Ll HEMLOCK SEMICONDUCTOR r.ORP. 10/79 01 /81 955533 DEVELOPMENT OF A POLYSILICON

HEMLOCK, MI PROCESS

LAMAR UNIVERSITY 10/75 02/81 954343 PROCESS FEASIBILITY STUDY BEAUMONT, TX

[] MASSACHUSETTS INST. OF TECH. 04/79 03/81 955382 INVESTIGATION OF THE CAMBRIDGE, MA HYDROGENATION OF SiCl4

a C. T. SAH ASSOCIATES 02/77 10/81 954685 STUDY OF EFFECTS OF IMPURITIES URBANA, IL IN SILICON MATERIALS

f

UNION CARBIDE CORPORATION 10/75 l 2/82 954334 SILANE TO SILICON EPSDU NEW YORK, NY

n WF.STJNGHOUSf ELECTRIC CORP. 10/75 07/81 954331 SOLAR tELL GRADE SILICON '

PITTSBURGH, PA DEFINITION

0 LARGE-AREA SILICON SHEET: '

APPL!fO SOLAR ENERGY COP.P. 05/78 07 /81 955089 SOLAR CELL PROCESS DEVELOPMENT CITY OF HIDUSTRY, CA

~ CORNELL Ut1IVERSI1Y 03/78 11 /81 954852 CHARACTERIZATION OF STRUCTURAL, ITHACA, NY AND CHEMICAL PROPERTIES OF

SILICON

[l CRYSTAL SYSTEMS 11 /75 03/81 954373 HEM SLICING PROCESS . SALEM, MA

KAYtX CORPORATION 12/77 09/81 954888 DEVF.LOPMENT OF ADVANCED METHODS

[] ROCHESTER, NY FOR CONTINUOUS CZ GROWTH .

KAYEX CORPORATION 03/79 09/80 955270 LOW COST r.zor.HRALSKI CRYSTAL ROCHESTER, NY GROWING TECHNOLOGY

D KAYEX CORPORATION 09/80 1 ?./81 955733 ADVANCED DZ GROWTH PPOCFSS ROCHESTER, NY

MATERIALS RESEAP.CH, nrr.. 06/80 07 /81 955676 MJAL YSIS OF DF.FECTIVE STRUCTURF.

[) CENTERVILLE, UT IN SILICON

MOBIL-TYCO SOLAR EtJERGY CORP. 10/75 12/80 954355 EDGE-DfFINED FILM-FE~ GROWT~ FPP. WALTHAM, MA SILICON GROWTH DEVELOPMENT

~ .

u u 85

I I

EXPECTED START COMPLETION CONTRACT TASK

I NAME DATE DATE ~IUMBER DESCRIPTION "

NORLIN INDUSTRIES 01/80 12/80 955563 SLICING OF SINGLE CRYSTAL AND CARLI Slf, PA POL YCRYSTALLJNE SILICON HIGOTS I USING MULTIBLADE SAW

SILTEC CORPORATION 12/79 10/80 955282 ENHANCED I.O. SLICING - SlLICON MENLO PARK, CA INGOTS

I SPECTROLAB, INC. 08/78 01 /81 955055 SILICON SOLAR CELL DEVELOPMENT, SYLMAR, CA FABRICATION AND ANALYSIS

UNIVERSITY OF MISSOURI 05/79 01 /81 955415 DETERMINE EFFECTS OF PRESSURES I COLUMBIA, MO OF REACTA~JT GASSES

WESTINGHOUSE ELECTRIC CORP. 10/80 01/82 955843 DENDRITIC WEB PROCESS DEVELOPMENT PITTSBURGH, PA

I ENCAPSULATION:

CASE WESTERN UNIVERSITY 03/77 12/81 954738 SYSTEM STUDIES--BASIC AGING AND I CLEVELAND, OH DIFFUSION

ILLHIOIS TOOL WORKS 09/79 08/81 955506 DEPOSIT OF ANTI-REFLECTJVE ELGIN, IL COATING BY ION PLATING

I ROCKWELL SCIENCE CENTF.R 03/77 12/81 954739 MATERIALS INTERFArE PROBLFM STUOY THOUSAND OAKS, CA

SPF.C'TROLAB, me. 11 /79 11 /81 955567 OESJGN, ANALYSIS, AND TEST I SYLMAR, CA VERIFICATION OF ADVANCED H!CAPSULATION SYSTF'MS

SPIRE CORPORATION 05/76 01 /81 954521 ENCAPSULATION--MATERIALS

I BEDFORD, MA PROPERTIES AND PROCESSING

SPRH!C,BORN LABORATORIES, INC. 05/76 08/82 954527 METHODS AND MATERIAL PROPERTIES ENFIELO, CT EVALUATION

UNIVERSITY OF MASSACHUSETTS 08/79 12/81 955531 PROCESS FOR POLYMERIC ULTRAVIOLET I AMHERST, MA STABILIZERS AND ABSORBERS

UNIVERSITY OF TORONTO 01 /80 12/80 955591 PHOTODEGRADATION MODELING

I TORONTO, ONTARIO, CAMADA

PRODUCTION PROCESS AND EQUIPMENT:

I APPLIED SOLAR ENERGY CORP. 03/79 09/81 955423 LABORATORY SERVICES CITY OF INDUSTRY, CA

ARCO SOLAR, HIC. 01 /79 04/81 95~278 AUTOMATFD SOLAP PANEL ASSEMBLY

I CHATSWORTH, CA

BFRND ROSS ASSOCIATES 05/80 05/81 955688 ECONOMI~AL IMPROVED THirK FILM SAN DIEGO, CA SOLAR CELL

I LOCKHf.EO MISSILE AND SPACE CO. 03/80 03/81 955696 LASF.R .AN~'EAL I NG SUNHYVALE, CA

MB ASSOCIATES 07/80 08/81 955699 AtlTnMATI<W EfllllPMENT flEVELOPMENT

I SAN RAMON, CA AND MODIFICATION

I 86

I

n n

EXPECTED

n START COMPLETION CONTRACT TASK NAME DATE DATE NUMBER DESCRIPTION

a MOTOROLA, INC. 09/77 11 /80 954847 PHASE II, PROCESS DEVELOPMENT PHOENIX,· AZ

I

MOTOROLA, I NC • 01 /79 11 /80 955328 THIN-SUBSTRATE CELLS PHOENIX, AZ

[] MOTOROLA. I NC. 10/80 04/81 955844 PROCESSING EXPERIMENTS WITH RTR .

PHOENIX, AZ SILICON MATERIAL

a SC 1rncr APPL ICATIClNS, INC. 06/80 02/81 955787 ANALYSIS OF SOLAR CELL MODULE McLEAN, VA EFFICIENCIES

SOLAREX CORPORATJON 09/77 12/80 954854 PHASF I I, PROCESS DEVELOPMEHT ROCKVILLE, MD a SOLAREX CORPORATION 11 /80 03/83 955902 MODULE EXPERIMENTAL PROCESS SYSTEM

. ROCKVILLE, MD DEVELOPMENT UNIT (MEPSDU)

[] SPECTROLAB, INC. 09/77 11 /80 954853 PHASE II, PROCESS DEVELOPMENT

SYLMAR, CA

SPECTROLAB, INC. 06/80 03/81 955725 HIGH RESOLUTION LOW r.osr CELL SYLMAR, CA CONTACT DEVELOPMENT a SPIP.E CORPORATION 01 /80 02/82 95~640 SOLAP rELL JUNCTION

. BEDFORD, MA

a UNIVERSITY OF PENNSYLVANIA 07/79 02/81 954796 AIITOMATF.D AP.RAY PHILADELPHIA, PA

WESTINGHOUSF. ELEr.TRir. CORP. 03/80 01 /81 95!;624 SILirON OENDT!RIC WEB PP.OCESS

t] PITTSBURGH, Pfi

.

WESTHlfiHOUSr FLErTRJC f.ORP. 11 /80 03/83 955909 MODULF. F.XPERIMENTAL PP.OfFSS SYSTEM PITTSBURf;H, PA DEVELOPMEHT UNIT (MEPSDU)

[J ENlutJEEr.ING: '

AIA RESEARCH fORPORATION l l /80 11 /81 955893 H'TF.r.RATED RESIDF.NTTAL PV

a WASHHIGTON, D.C. DEVELOPMENT

BOEHIG COMPANY 08/77 09/80 954833 FEASIBILITY STUOY--SOLAR DOME . SEATILE, WA ENCAPSULATION

[) BURT HILL KOSAR RITTELMANN 10/79 10/80 955614 OPFP.ATJOtl-MAHITf.NANCE COST DATA BUTLER, PA FOR RESIDENTIAL PHOTOVOLTAICS

.

BUPT HILL KOSAR RITTELMANN 04/80 03/81 955698 r.Of>t1ERCIAL/INDUSTRIAL

~ BUTLER, PA PHOTOVOLTAIC REQUIREMENTS

CARNEGIE-MELLON UNIVERSITY 08/80 02/81 955846 EXPLOP.ATOP.Y STUOY OF PRODUCT .

PITTSBURGH, PA SAFETY LIABILITY CONSIDERATIONS FOR PHOTOVOLTAit MODULE/ARRAY

[l DEVICES CLEMSON UNIVERSITY 12/77 10/81 954929 SOLAR CELL RELIABILITY TEST

CISMSON, SC

u GF.HF.RAL ELECTRIC CORP. 10/80 11 /81 955894 INTEGRATFD RfSIOENTJAL PHILADELPHIA, PA. PHOTOVOLTAIC ARRAY fJEVELOPMENT

u .

~ 87

START NAME DATE

IIT RESEARCH INSTITUTE 03/80 CHICAGO, ILL

UNDERWRITERS LABORATORIES, INC. 05/79 MELVILLE, NY

LARGE-SCALE PRODUCTION:

APPLIED SOLAR ENER~Y CORP. 05/79 CITY OF INDUSTRY, CA

ARCO SOLAR, INr.. 07 /79 CITY OF INDUSTRY, CA

GD!ERAL ELECTRIC CO. 05/79 PHILADELPHIA, PA

MOTOROLA, I Nf. • 05/79 PHOENIX, AZ

SENSOR TECH•IOLOGY (PHOTOWATT) 04/79 PHOENIX, AZ

SOLAREX CORPORATimJ 05/79 ROCKVILLE, MD

SOLAR POWER 06/79 WOBURN, MA

EXPECTED COMPLETION CONTRACT

DATE NUMBER

01 /81 955720

09/81 955392

12/80 955409

08/80 955402

08/80 955401

12/80 955406

03/81 955410

02/81 955404

12/80 955403

88

TASK DESCRIPTION

RELIABILITY ENGINEERING TECHNICAL SUPPORT

SOLAR ARRAY AND MODULE SAFETY REQUIREMENTS

BLOCK IV

BLOCK IV

BLOCK IV

BLOCK IV

BLOCK IV

BLOCK IV

BLOr.K IV


n u vlt u

n Li

[] ' '

0 n \:J

[] I I

a ,·

a . '

[l '

u I l

.

~ I .

LSA PROJECT PUBLISHED DOCUMENTS*

Document No. Author

5040-29 DOANE, J. W. ERDA/JPL-1012-76/3 June, 1976

Title

The Cost of Energy From Utility-owned Solar Electric Systems

5101-2 PROJECT OFFICE Proceedings·of the First Task Integration Meeting ERDA/JPL-1012-76/1 January, 1976

5101-5 PRQJECT OFFICE Proceedings of the Second Project Integration Meeting ERDA/JPL-1012-76/4 April, 1976

5101-7 PROJECT OFFICE LSA First Quarterly Report~ April to June 1976 ERDA/JPL-1012-76/6 October, 8, 1976

5101-8 PROJECT OFFICE Proceedings of the Third Project Integration Meeting ERDA/JPL-1012-76/7 July 30, 1976

5101-10 PROJECT OFFICE ERDA/JPL-1012-77/1

5101-12 ZOUTENDYK, J. October 28, 1976

5101-13 GONZALEZ, C. C. February 14, 1977

5101-14 EDELSON, E. January 26, 1977

LSA Second Quarterly Report - July to September 1976

Progress in Silicon for Terrestrial Photovoltaic Crystal Technology Solar Energy Conversion

Availability of Ultraviolet Radiation Data (for Encapsulation System Design)

Preliminary Analysis of Industrial Growth and the Factors that Affect Growth Rate

5101-15 CHAMBERLAIN, R. G. SAMICS (Solar Array Manufacturing Industry Costing September 1977 Standards) Workbook

5101-16 LSA ENGR. AREA Rev. A November 1, 1978 DOE/JPL-1012-78/10

5101-19

5101-20

5101-21 Rev. B

5101-24 ·ERDA/ JPL-1012-77 /2

5101-31

5101-32 DOE/JPL-1012-77/3

MOORE, D. February 28, 1977

CANTU, A.H. February 28, 1977

BISHOP/ANHALT November 3, 1978

PROJECT OFFICE

STULTZ/WEN July 29, 1977

PROJECT OFFICE__

Block IV Solar Cell Module Design and Test Specification for Intermediate Load Center Applications

Cyclic Pressure-Load Developmental Testing of Solar Panels

Test Program on Low-Cost Connector For Solar Array Modules

Acceptance/Rejection Criteria for JPL/LSA Modules

Project Quarterly Report-3 for the Period October 1976 to December 1976

Thermal Performance Testing and Analysis of Photovoltaic Modules in Natural Sunlight

Quarterly Report-4 for the Period January 1977 to March 1977

5101-33 CHAMBERLAIN/ASTER Interim Price Estimation Guidelines: A Precursor and September 10, 1977 an Adjunct to SAMIS Ill, Version One

5101-36 SMOKLER, M. User Handbook for Block II Silicon Solar Cell Modules October 15, 1977

* Documents with DOE/JPL numbers are available from: Technical Information Center P.O. Box 62 Oak Ridge, TN 37830 Phone: (615) 576-1304

89

Document No.

5101-39

5101-40

5101-43

5101-45

5101-46 DOE/JPL-1012-77/4

5101-51

5101-53 DOE/JPL-1012-77/6

5101-54 Vol. I DOE/JPL-1012-78/1

5101-54 Vol. II DOE/JPL-1012-78/1

5101-55 DOE/JPL-1012-78/2

5101-56 DOE/JPL-1012-78/3

5101-57 DOE/JPL-1012-78/7

5101-58

5101-59

5101-60 Rev. B

5101-61

Author

JAFFE, P. August 3, 1977

COULBERT, C. D. June 8, 1977

GRIPPI, R. A. October 7, 1977

GONZALEZ, C. C. December 6, 1977

PROJECT OFFICE June 1977

PRATURI/LUTWACK/ HSU July 17, 1977

O'DONNELL/LEIPOLD/ HAGAN March 1, 1978

SMITH, J. L. April 1978

SMITH, J. L. April 1978

PROJECT OFFICE

TURNER, G. B. March 1, 1978

CHEN, C. P. February 22, 1978

ESTEY, R. S. March 15, 1978

CHAMBERLAIN, R. G. February 1, 1978

FIRNETT, P.J. April 21, 1980

CUDDIHY, E. April 13, 1978

5101-62 MOORE/WILSON DOE/JPL-1012-78/6

5101-65 LSA ENGR. AREA DOE/JPL-1012/78/7A March 24, 1978

5101-68 Rev.A

,5101-69

ASTER, R. W. January 15, 1980

DAUD/KOLIWAD June 15, 1978

Title

LSA Field Test Activity System Description

Development & Validation of A Life-Prediction Methodology for LSA Encapsulated Modules

Module Efficiency Definitions, Characteristics and Examples

Environmental Hail Model for Assessing Risk to Solar Collectors

Project Quarterly Report-5 for the Period April 1977 to June 1977

Chemical Vapor Deposition of Silicon from Silane Pyrolysis

Compatability Studies of Various Refractory Materials in Contact with Molten Silicon

Historical Evidence of Importance to the Industrialization of Flat-Plate Silicon Photovoltaic Systems: Executive Summary

Historical Evidence of Importance to the Industrialization of Flat-Plate Silicon Photovoltaic Systems

Project Quarterly Report-6 for the Period July 1977 to September 1977

Structure of Deformed Silicon and Implications for Low-Cost Solar Cells

Multi-Wire Slurry Wafering Demonstrations

Measurement of Solar and Simulator Ultraviolet Spectral Irradiance

SAMICS Usage No. 1

Standard Assembly-Line M~nufacturing Industry Simulation (SAMIS) Computer Program User's Guide -Release 3

Encapsulation Material Trends Reliability 1986 Cost Goals

Photovoltaic Solar Panel Resist - Simulated Hail

Photovoltaic Module Design, Qualification and Testing Specification

Price Allocation Guidelines - January 1980

Effect of Grain Boundary in Silicon Sheet on Minority Carrier Diffusion Length and Solar Ce 11 Efficiency

5101-70 Rev. B

CHAMBERLAIN/FIRNETT Standard Assembly-Line Manufacturing Industry /HORTON Simulation (SAMIS) Design Document~ Release 3 April 21, 1980

90

I I I .

I I .

I I I I I I I I I I I I I I

fu fil]

tl ~ Id

a a

l]

a n u n u

D .

I .

a n Li

n l1l

u I .

u '

I

Document No.

5101-71 Rev. B

5101-72

5101-73 DOE/JPL-1012-78/8

5101-75

5101-76 DOE/JPL-1012-78/9

5101-77

5101-79

Author Title

CHAMBERLAIN/FIRNETT Standard Assembly Line Manufacturing Industry /HORTON Simulation {SAMIS) Computer Program Source Code -April 21, 1980 Release 3

MAXWELL, H. June 15, 1978

VON ROOS, O. May 31, 1978

SMITH, J. L. May 30, 1978

STULTZ, J. W. July 31, 1978

GUPTA, A. August 10, 1978

GUPTA, A. August 18, 1978

Encapsulant Candidate Materials for 1982 Cost Goals

Determination of Bulk Diffusion Lengths for Angle-Lapped Semiconductor Material via the Scanning Electron Microscope - A Theoretical Analysis

The Penetration of che International Market by Domestically Produced Photovoltaic Power Systems: A Survey of Recent Estimates

Thermal and Other Tests of Photovoltaic Modules Performed in Natural Sunlight

Photodegradation of Polymeric Encapsulants of Solar Cell Modules

Effe~t of Photodegradation on Chemical Structure and Surface Characteristics of Silicon Pottants Used in Solar Cell Modules

5101-81 PROJECT OFFICE Project Quarterly Report-7 for the Period October 1977 to December 1977 DOE/JPL-1012-78/13 November 15, 1978

5101-82 DOE/JPL-1012-79/6

SMOKLER, M. I. November 15, 1979

5101-83 LSA ENGR. AREA DOE/JPL-1012-78/14 November 1, 1978

5101-84 DOE/JPL-1012-78/11

HOFFMAN/MILLER October 15; 1978

User Handbook for Block III Silicon Solar Cell Modules

Block IV Solar Cell Module Design and Test Specification for Residential Applications

Bias-Humidity Testing of Solar Modules

5101-85 DOE/JPL-1012-78/12

JAFFE, P. LSA Field Test Annual Report August 1977 to

5101-88 JPL Publ. 79-14

5101-91, Vols. I-III DOE/JPL-1012-25 JPL Publ. 79-103

5101-93 DOE/JPL-1012-79/5

5101-94 DOE/JPL-1012-78/17

5101-96 DOE/JPL-1012-23

5101-98 DOE/JPL-1012-79/1

September 15, 1978 August 1978

PROJECT OFFICE

SMITH, J. H

CHAMBERLAIN, R. G. January 15, 1979

ASTER, R. December 1, 1978

Tsou/Schwartz March I, 1979

GRIFFITH, J. S. January 1, 1979

Project Quarterly Report-8 for the Period January-March 1978

Handbook of Solar Energy Data for South-Facing Surfaces in the United States

Volume I: An Insolation, Array Shadowing, and Reflector Augmentation Model Volume II: Average Hourly and Total Daily Insolation Data for 235 Localities (Alaska-Montana) Volume III: Average Hourly and Total Daily Insolation Data for 235 Localities (North Carolina-Wyoming) ·

A Normative Price for a Manufactured Product: The SAMICS Methodology

Volume I: Executive Summary Volume II: Analysis

Economic Analysis of a Candidate 50¢/Wpk Flat-Plate Photovoltaic Manufacturing Technology

Module Performance Assessment: Laboratory and Field Environment

Environmental Testing of Block II Solar Cell Modules

91

Document No.

5101-99 DOE/JPL-1012-3

5101-100 DOE/JPL-1012-4 JPL Publ. 79-16

5101-102

5101-103 DOE/JPL-1012-79/8

5101-104 DOE/JPL-1012-7

5101-105 DOE/JPL-1012-20

5101-106 OOE/JPL-1012-21

5101-107 OOE/JPL-1012-18

5101-108 OOE/JPL-1012-19

5101-109

5101-112 DOE/JPL 1012-27

5101-131 OOE/JPL-1012-49 JPL Publ. 80-87

5101-133 OOE/JPL-1012-29 JPL Publ. 79-88

5101-134 OOE/JPL-1012-30 JPL Publ. 79-96

5101-135 OOE/JPL-1012-31 JPL Publ. 79-92

5101-137 OOE/JPL-1012-32 JPL Publ. 79-102

5101-138 OOE/JPL-1012-36

5101-139 OOE/JPL-1012-34 JPL Publ. 79-116

5101-141 OOE/JPL-1012-38 JPL Publ. 80-5

Author

PROJECT OFFICE

PROJECT OFFICE

SLONSKI, M. L. February 15, 1979

REPAR, J. January 1, 1979

GRIFFITH, J. S. January 1, 1979

PRATURI, A. K. April 15, 1979

PRATURI, A. K. April 1, 1979

RHEIN, R. A. April 15, 1979

RHEIN, R. A. April 15, 1979

PROJECT OFFICE

PROJECT OFFICE

Hoffman/Maag November 1, 1980

PROJECT OFFICE

GRIFFITH, J. S. September 1, 1979

LAUE/GUPTA September 21, 1979

CHEN, C. P. October 15, 1979

LSA ENGINEERING January 15, 1980

SALAMA, A. M. November 1, 1979

JAFFE, Peter December 15, 1979

Title

Project Quarterly Report-9 for the Period April-June 1978

Project Quarterly Report-10 for the Period July-September 1978

Energy Systems Economic Analysis (ESEA) Methodology & User's Guide

Experience with Silicones in Photovoltaic Modules

Environmental Testing of Block II Solar Cell Modules

Modeling of Silicon Particle Growth; a Progress Report

On the Modeling of Silane Pyrolysis in a Continuous Flow Reactor

Purification of Silicon by the Silicon Fluoride Transport Process - A Thermochemical Study

Silicon Preparation and Purity from the . Reaction of Sodium with Silicon Tetrafluoride

and Silicon Tetrachloride - A Thermochemical Study

Quarterly Report-11 for the Period October· 1978-December 1978 and Proceedings of the 11th Project Integration Meeting

Progress Report 12 for the Period January 1979 to April 1979 and Proceedings of the 12th Project Integration Meeting

Photovoltaic Module Soiling Studies May 1978-0ctober 1980

· Progress Report 13 .for the Period April 1979 to August 1979 and Proceedings of the 13th Project Integration Meeting

Environmental Testing of Block III Solar Cell Modules - Part 1: Qualification Testing of Standard Production Modules

Reactor for Simulation and Acceleration of Solar Ultraviolet Damage

Fracture Strength of Silicon Solar Cells

1982 Technical Readiness Module Design and Test Specification - Intermediate Load Applications

Characterization of Deliberately Nickel-Doped Silicon Wafers and Solar Cells

LSA Field Test Annual Report August 1978-August 1979

92


[I

a I !

[]

a

a

UV uJ

[] I .

[] I I .

(J

Document No.

5101-142 DOE/JPL-1012-42 JPL Publ. 80-21

5101-143

5101-144

5101-146 DOE/JPL-1012-37 JPL Pub 1. 80-25

5101-147 DOE/JPL-1012-40 JPL Pub 1. 80-12

5101-148 DOE/JPL-1012-41 JPL Pub!. 80-34

5101-150

5101-151 DOE/JPL-1012-44 JPL Publ. 80-27

5104-154

5101-155

5101-156 Rev.A

5101-158 Rev.A

5101-159 Rev.A

Author

PROJECT OFFICE

PROJECT OFFICE January 1980

CUDDIHY, E. F. January 15, 1980

Leipold/Radics/ Kachare February 15, 1980

BOUQUET, F. L. February 1, 1980

MOORE, D. M. March 1, 1980

CHRISTENSEN, E.

PROJECT OFFICE April 1980

CHAMBERLAIN/ASTER/ FIRNETT April 21, 1980

CHRISTENSEN, E. June 1980

FIRNETT, P.J. November 17, 1980

ASTER/CHAMBERLAIN/ MILLER/FIRNETI November 17, 1980

Title

Progress Report 14 for the Period August 1979 to December 1979 and Proceedings of the 14th Project Integration Meeting

Electricity from Photovoltaic Solar Cells -Status of Low-Cost Solar Array Project

Encapsulation Materials Status to December 1979

Cost of Czochralski Wafers as a Function of Diameter

Glass for Low-Cost Photovoltaic Solar Arrays

Proposed Method for Determining the Thickness of Glass in Solar Collector Panels

Electricity from Photovoltaic Solar Cells (Black & White Update of 5101-143)

Progress Report 15 for the Period December 1979 to April 1980 and Procedings of the 15th Project Integration Meeting

SAMICS Cost Accountable Catalog - Version 4

Electrical Power from Solar C~lls (Update of 5101-150)

Improved Price Estimation Guidelines (IPEG) Computer Program User's Guide - Release 2

Improved Price Estimation Guidelines (IPEG) Design Document - Release 2

CHAMBERLAIN/FIRNETT Improved Price Estimation Guidelines (!PEG) /MILLER Computer Program Source Code - Release 2 November 17, 1980

93

PASADENA AREA

0 TO JPL

BLDG . 512 145 NO, ALTADENA D~.

>,

"' ~ .>t. ~

"' C.

0 >,

~-<

U,J

> 0 ~ U,J

(.'.) z <( ex: 0

.; >

<(

0 0, C: (I) ~

"' ::;

Und e r -

g r ound ~ Pa rking

Ent rance/

v"> 0 :,,: (.'.) <(

0 z 0 UJ -' z

"" "" u UJ -' UJ

~ <( ~

:,,: -' -' :::: <( -' u.. UJ

-' :i: <(

COLORADO

GR E N

CALIFORNIA r- -- , I I

_____..

Ex hibition Bldg.

8 T en nis

~

Apts.

CALIFORNIA INSTITUTE

O F TECHNOLOGY

PASADENA CENTER

Cc:iloradc Blvd.

Gr een St. --Con fere nce

Civ ic ! Bldg._....-/" ~

Aud . X

'

8 Ice C ha let

H o liday Inn 8 -Co rdova St.

De l Ma• B.vd

BLDG 502 2500A E. FOOTHIL L BLVD

BLDG 507 2500B E. FOOTHILL BL VD

BLDG. 506 133 N O . ALTADENA DR .

t ~

~ .;

.; > <(

> <( V)

~ "O .0

u 0 a: ::,

w V)

0 ...J

~ p . a r k ,ng

+E ntranc e

- R!,g1stration : Lobby, lower f loor

E:nt r ance s

Under ground pa rkin g has en trance t o con f erence building

17th Project Integration Meeting Handout PIM... · with you to the PIM! ! ~ LI n . . ~ . . G . . n...

Documents

Transcript of 17th Project Integration Meeting Handout PIM... · with you to the PIM! ! ~ LI n . . ~ . . G . . n...