Surface Analysis

LEDN-02

Analysis Techniques

SampleProbe

Response

Modified Probe

Probe: photo Response: photo

electron electron

ion ion

phonon phonon

APPLIED MICROANALYSIS LABSAPPLIED MICROANALYSIS LABS

Analysis Techniques

phonon

photo photoXRF, TXRF, FTIR, Raman

electron electron

ionion

phonon

SIMS, RBS, ISS, GDMS

Scanning Acoustic Microscopy

ESCA

EDS

PIXE, G

DOS

SEM, TEM, AES, EELS

LAMM

A

LEDN-03APPLIED MICROANALYSIS LABSAPPLIED MICROANALYSIS LABS

LEDN-004

Analysis Techniques

Elemental Molecular

Surface ( <10 Å)

Thin film ( <100 Å - 1m)

Bulk ( > 10m)

Types of information provided by chemical analysis


LEDN-005

Surface and Thin film Analysis

Surface Thin Film Elemental Molecular

TXRF

EDS

RBS

AES

ESCA

SIMS


100%

100 ppm

1%

1 ppm XR

F

ES

CA

AE

S

RB

S

SIM

S

ED

X

100Å

10 µm

0.1 µm

1 µm

1 µm

0.1 µm

10 µm

100 µm

1 mm

VD

D

E

SE

NS

ITIV

ITY

SP

AT

IAL

R

ES

OL

UT

ION

QU

AN

TIT

AT

ION

DE

PT

H

RE

SO

LU

TIO

N

LEDN-006

SIMS vs. Other Techniques


LEDN-07

Analysis Principle

K (1s)

L1(2s)

L 2,3(2s)

Atom Ion

e-

h

Excitation

Photoelectron

Eb= h-Ek-

Relaxtation

h

ESCA

EDS, XRF AES Auger electron

KL1L 2,3


LEDN-08

Analysis Principle

10-100 Å electron escape depth

1m Electron excitation depth

Auger electrons (surface)X-ray fluorescence

Primary Electrons

10-100 Å electron escape depth

100-1000 m X-ray excitation depth

photoelectrons (surface)X-ray fluorescence

Incident X-rays X-ray fluorescence (surface)

Incident X-rays

TRXF

Depth information determined either by excitation depth or by escape depth


LEDN-09

+

+

+Primary ions (~10 keV)

Sam

ple

ato

msAbsorbed molecules

Sputtered atoms

SIMS Principle

++

-

++Secondary ions

Mix

ing

range (

~100

Å)

Esca

pe ra

nge

(~10 Å

)

Desorbedmolecular ions

Sputtering event


LEDN-10

SIMS Technique Schema

ION

SOURCE

Sample

MASSSPECTROMETER

DETEC

TO

R

m/q

MASS SPECTRUM

m

DEPTH PROFILE

X-Y

IMAGE

VACCUM


Magnetic sector Quadrupole Time of Flight

LEDN-11

SIMS Instrument Type

r = k/B(m/q)1/2

M-M

M

M+M

Vo(t) = Vc+Vs cost

t-t ~ M-M

t ~ M

t+t ~ M+M

ion pulse

Detection&

Registration

m/q ~ B m/q ~ V(f) m/q ~ t


primary ion

ion: elemental information

ion: molecular information

<< A = A Static SIMS Dynamic SIMS

Primary ion dose <1E12 ions/cm2 >1E12 ions/cm2

Information Chemical Elemental

Analysis Only surface Depth profile

Instrument TOF & Quad Magnetic & Quad

Ion damage section, Desorption area, D

Bombarded surface, A

LEDN-12

Dynamic vs. Static SIMS


LEDN-13

Comparison of SIMS Instruments

MagneticSector

Quadrupole Time ofFlight

Transmission High (~10-1) Low (~10-3) High (~10 -1 )

Mass range Low (< 500) Low (< 600) Unlimited

Mass resolution High ~ 10000 Low ~ 500 High ~ 10000

Detection speed Low High Quasi-parallel

Chargecompensation

Difficult Easy Easy

Analysis modes Bulk analysisDepth profiling(100Å-100m)

Imaging

Bulk analysisDepth profiling

(0Å-10m)Imaging

Surface AnalysisDepth profiling

(0Å-1m)Imaging


Analytical Condition

LEDN-14

H He

Li Be B C N O F Ne

Na Mg Al Si P S Cl Ar

K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn

Fr Ra Ac

Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Tm Yb Lu

Th Pa U

Oxygen bombardment & Positive ions

Cs bombardment & Negative ions

Cs bombardment & Oxygen bombardment


LEDN-15

Detection Limits (atoms/cm3) in InP, GaAs, GaNFor electropositive elements

Element M+ (O2+) M- (Cs+)

Li 3E13 1E16Be 3E14 1E20B 1E15 3E15Na 3E14 2E17Mg 1E14 1E20Al 2E15 1E17K 2E14 2E18Ca 3E14 1E20Ti 2E14 1E18V 1E14 1E17Cr 1E15 2E17Mn 3E14 1E18Fe 1E15 3E17Ni 1E16 5E17Cu 3E16 1E16Zn 1E16 1E20Sr 5E15 1E20Y 1E17 1E20Zr 1E15 4E17Nb 1E16 1E18Mo 1E16 1E18Cd 5E16 1E21In 3E15 3E17

SIMS Detection Limit


LEDN-16

Detection Limits (atoms/cm3) in GaAs,InP and GaNFor electronegative elements

Element M- (Cs+) M+ (O2+)

H 2E17 2E18

C 1E16 2E18

N 5E15 (NGa-) 5E18

O 1E16 1E20

F 2E14 5E16

P 2E15 1E16

Si 2E15 1E16

S 1E15 1E19

Cl 3E15 2E17

Ge 5E15 2E16

Se 5E14 2E17

Br 5E13 1E17

Te 1E15 2E17

Ag 2E16 2E16

Au 1E15 1E17

SIMS Detection Limit


Depth (m)

Conce

ntr

ati

on(a

t/cm

3)

P implantation in Si(2E12 atoms/cm2, 300 keV)

1E13 at/cm3

LEDN-17

High Mass Resolution Analysis for P in Si

High Sensitivity


LEDN-18

Depth profiling of Multi-Quantum wells InGaAsP/InGaAs

SIMS Depth Resolution

Lz = 110 Å

Lz = 125 Å


SiC fiber in a Ti matrix (V-doped)

LEDN-19

Ti

C

Si

V

50 m

Ga+ primary ion (30 keV, 50 pA)

Ti+: 10s; Si+: 200s; V+: 100s; C+: 200s

SIMS Image Analysis


• Enhance production yield

SIMS Analysis for GaN LEDsSIMS Analysis for GaN LEDs

Wafer ControlWafer Control

• LED wafers

• Test wafers

• Purity control (C,H,O,metals)

• Doping control (Si, Mg)

• Layer thickness (Growth rate)

• Interface quality

• Film composition (AlGaN,InGaN)

SIMS SIMS analysisanalysis

Calibration &Calibration & Optimization of GrowthOptimization of Growth

GaNGaNEpitaxyEpitaxy

GrowthGrowth

Failure analysisFailure analysisReverse engineeringReverse engineering

LED dies

• Reduce R&D cycle timeReduce R&D cycle time

APPLIED MICROANALYSIS LABSAPPLIED MICROANALYSIS LABSLEDN-20


SIMS for AlInGaP LED

LEDN-21

1E+15

1E+16

1E+17

1E+18

1E+19

1E+20

1E+21

0 2 4 6 8 10 12

DEPTH (microns)

CO

NC

EN

TR

AT

ION

(a

tom

s/c

c)

Ga (a.u.)Al (a.u.)

Mg

O

Te

Depth (micron)

Co

nc

en

tra

tio

n (

ato

ms/

cm3)

AlI

nG

aPA

lIn

GaP

APPLIED MICROANALYSIS LABSAPPLIED MICROANALYSIS LABSLEDN-22

SIMS for GaN LED

1E+15

1E+16

1E+17

1E+18

1E+19

1E+20

1E+21

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

DEPTH (microns)

CO

NC

EN

TR

AT

ION

(a

tom

s/c

c)

Mg

Al (a.u.)

Si

In (a.u.)

Depth (micron)

Co

nc

en

tra

tio

n (

ato

ms/

cm3)

InG

aNIn

GaN


1E+15

1E+16

1E+17

1E+18

1E+19

1E+20

1E+21

0 0.5 1 1.5 2 2.5 3 3.5

Si

Al (a.u.)

Ga (a.u.)

O

Zn

H

Depth (micron)

Co

nc

en

tra

tio

n (

ato

ms/

cm3)

AlI

nG

aPA

lIn

GaP

SIMS for AlInGaP LD

LEDN-23


SIMS for AlGaAs VCSEL

LEDN-24

1.E+15

1.E+16

1.E+17

1.E+18

1.E+19

1.E+20

1.E+21

0 1 2 3 4 5 6 7 8 9

DEPTH (microns)

CO

NC

EN

TR

AT

ION

(at

om

s/cc

)

Al (a.u.)

CSi

O

Depth (micron)

Co

nc

en

tra

tio

n (

ato

ms/

cm3)

VC

SE

LV

CS

EL


SIMS for LED dies

LEDN-25

GaN LED dieGaN LED die

SIMS cratersSIMS craters

AlInGaP LED die AlInGaP LED die

SIMS cratersSIMS craters

• Doping concentration and distribution• Undesirable Impurities• Layer structure control

Failure analysisFailure analysis• Epi-layer structure• p- and n-type metal stacks• Passivation layers

Reverse engineeringReverse engineering

PL on the beveled surfaceSIMS profile

A B C D

Comparison between PL and SIMS

LEDN-26

Composition Analysis by SIMS

AlxGa1-xAs composition by MCs+ technique



Composition Analysis by Auger

LEDN-27

Depth profiling of the top layers of GaN die

0

10

20

30

40

50

60

70

80

90

100

0 500 1000 1500 2000

Depth (A)

Au

ge

r S

ign

al (

~%

)

AuGaInNiOSi

SiO2 AuNi

Surface Analysis

Technology

Transcript of Surface Analysis