CeNSE ALD user and training documentation Part 1: Selected … · 2020. 4. 7. · Cambridge...

CeNSE ALD user and training documentation

Part 1: Selected pages from Official Manual

Part 2: Basic growth process

Part 3: Official training tutorial from Manufacturer.

Part 4: Our valves and Precusrsors (Needs edit)

Part 1: Selected pages from Official Manual

Savannah 100 Atomic Layer Deposition System

Customer Product Manual

Cambridge NanoTech Inc. 23 Perry Street

Cambridge, MA 02139 USA

© 2004 Cambridge NanoTech Inc. All rights reserved

2

Cambridge NanoTech Inc. welcomes requests for information, comments and inquiries about its products.

Address all correspondence to:

Cambridge NanoTech Inc. 23 Perry Street

Cambridge, MA 02139 USA

This manual is also available in other languages upon written request.

Notice

This is a Cambridge NanoTech Inc. publication which is protected by copyright. Original copyright date 2004. No part of this document may be photocopied, reproduced, translated to another language, or published on-line without the prior written consent

of Cambridge NanoTech Inc. The information contained in this publication is subject to change without notice.

Trademarks

Cambridge NanoTech Inc. and Savannah 100, are trademarks of Cambridge NanoTech Inc.

Kalrez and Viton are registered trademarks of E.I. DuPont de Nemours & Co.

VCR is a registered trademark of Swagelok company.


6

Personal Safety To prevent injury follow these instructions.

• Do not operate or service equipment unless you are qualified andhave fully read and understood the manual and warning labels on the system. Contact Cambridge NanoTech Inc. with any questions in case of uncertainties.

• Do not operate equipment unless safety guards, doors, or covers areintact and automatic interlocks are operating properly. Do not bypass or disarm any safety devices.

• Before adjusting or servicing equipment, or touching any of theparts, turn off the heaters in the software, wait until all temperature sensors are at room temperature, then shut off the power supply and unplug the main power and wait until all unmonitored parts have cooled down. Lock out power and secure the equipment.

• Relieve (bleed off) pneumatic pressure before adjusting or servicingpressurized systems or components, such as gas cylinders. Never disconnect high pressure gas cylinders without specific knowledge. Refer to your supplier for instructions.

• Obtain and read Material Safety Data Sheets (MSDS) for allmaterials used. Follow the manufacturer’s instructions for safe handling and use of materials, and use recommended personal protection devices.

• To prevent injury, be aware of less-obvious dangers in the workplacethat often can not be completely eliminated, such as hot surfaces, sharp edges, energized electrical circuits, and moving parts that can not be enclosed or otherwise guarded for practical reasons.


7

Fire Safety To avoid a fire or explosion, follow these instructions.

• Do not place flammable materials underneath, on or near the unit.Do not place paperwork, clothing etc. on or near the unit.

• Do not run the system unattended; do not run the system overnight.

• Do not heat materials to temperatures above those recommendedby the manufacturer. Make sure heat monitoring and limiting devices are working properly. Note the maximum temperature settings for different parts. Solenoid valves are rated to 115

oC and should not be

heated above that temperature. Center heater maximum temperature is 400

oC, while outer heater should not be set higher then 250

oC

because of the Kalrez™ O-ring. The tee and flexible bellows of the pumping line should not be heated above 180

oC. Temperature of the

precursors should not exceed safety or decomposition temperature of the chemical used. Maximum for the precursor heater jacket is 180 oC.

• The pump may exhaust small amounts of unreacted precursor.Since Cambridge NanoTech Inc. does not supply the chemicals, responsibility for safe venting and exhausting lies with the customer. General exhaust recommendations include using inert pumping fluid such as Fomblin SV, fireproof metallic exhaust lines to prevent fire. Refer to local codes or your material MSDS for guidance. Minimize precursor use. Do not add vapor traps in the pumping line, upon exposure to air large amounts of trapped precursor may ignite or cause chemical burns.

• Know where emergency stop buttons, shutoff valves, and fireextinguishers are located.

• Clean, maintain, test, and repair equipment according to theinstructions in your equipment documentation.

• Use only replacement parts that are designed for use with originalequipment. Contact your Cambridge NanoTech Inc. representative for parts information and advice.


8

Electrical Safety

Chemical Safety

Action in the Event of a

Malfunction

Disposal

To avoid electric shocks, follow these instructions. • Ground the stainless steel cabinet with green wire attached to the back panel. • Turn off and unplug the electronic control unit prior to connecting or disconnecting any sensor, heater, valve or other components. • Do not disconnect live electrical circuits while working with flammable materials. Shut off main power first to prevent sparking. To avoid chemical hazards, follow these instructions. • Know the nature of the precursors you are working with (read MSDS). Some precursors such as trimethylaluminum are pyrophoric, they burn upon exposure to air. Precursors should never be disconnected from the manual valve they were supplied with. Make sure that manual valve is closed before removing the precursor-valve combination from the system. Pump/purge the space between solenoid valve and manual valve before disconnecting any precursor. Always wear proper protection equipment when removing precursors. Precursor replacement should only be conducted by qualified personnel. Read the section on precursor removal before proceeding. Cambridge NanoTech Inc. can be reached for safety assistance with precursor replacement/removal procedure, although the final responsibility lies with the user. If a system or any equipment in a system malfunctions, shut off the system immediately and perform the following steps: • Disconnect and lock out system electrical power. Close valves and relieve pressures. • Identify the reason of the malfunction and correct it before restarting the system. Dispose of equipment and materials used in operation and servicing according to local codes.


9

Section 2

Theory

Atomic Layer Deposition:

Principle of Al2O3 formation

Modes of Operation

Pyrophoric Precursors

Atomic Layer Deposition (ALD) is a technique that allows growth of thin films, atomic layer by layer. Deposition of Al2O3 from water and trimethylaluminum (TMA) precursors will be used to illustrate the principle of ALD. Recipes for other materials can be found in the literature. The chemical principle of Al2O3 growth from water and TMA is outlined in Figure 1. Five steps can be identified: 1. Put in a sample which is hydroxilated from exposure to air,

oxygen or ozone (Figure 1A).

2. Pulse the TMA precursor; TMA will react with the OH groups on the surface. TMA does not react with itself and the monolayer formed passivates the surface (Figure 1B, 1C).

3. Remove unreacted TMA molecules by evacuation and/or purging with nitrogen (Figure 1D).

4. Pulse water (H2O) into the reactor. This will remove the CH3 groups, create Al-O-Al bridges, and passivate surface with Al-OH. CH4 (methane) is formed as a gaseous byproduct (Figure 1E, 1F).

5. Remove unreacted H2O and CH4 molecules by evacuation and/or purging with nitrogen (Figure 1G).

Steps (a)-(g) form a cycle. Each cycle produces a maximum of 1.1 Å of Al2O3 depending on temperature.Thus, 100 cycles produces 11 nm of Al2O3. There are two main modes of operation: 1. Continuously flowing nitrogen carrier gas while pulsing (adding)

precursor and pumping continuously 2. Pulsing precursors with stop valve closed and pumping in-

between pulses This research system can operate in either mode. Trimethylaluminum (TMA) is a liquid at room temperature and is pyrophoric. This means that it burns upon exposure to air. TMA reacts with water vapor in the air. For this reason, the TMA bottle may only be opened in a glove box with inert atmosphere by experienced professionals such as at the chemical supply companies (Strem, Sigma-Aldrich etc).


10

Process Flow

Fig. 1. Chemical reactants in the ALD process are introduced into the deposition chamber as gases, and supplied in pulses delivered to the reactor at different times. Reactants are separated from one another in the flow stream by a purge gas or evacuation. Each reactant pulse chemically reacts with the wafer surface, making ALD a self-limiting process capable of precise monolayer growth.


20

Section 4

Operation

Software Installation

READ ALL INSTRUCTIONS IN THEIR ENTIRETY BEFORE

OPERATION Software for the Savannah 200 ALD system can be installed from the supplied CD or downloaded from our web site: http://www.cambridgenanotech.com We recommend downloading software from our website in order to have the latest revision of the control program. 1. If the PC used with the ALD system does not have LabView

package installed, install LabView runtime engine by opening the

file LVRunTimeEng.exe

2. Install LabJack drivers by opening the file LabJack_drivers.exe 3. Install ALD control program by opening the file

Savannah_200_setup.exe After installation the control program can be started from the “Savannah 200” shortcut on the desktop or through the Start menu.

http://www.cambridgenanotech.com/


21

Preparation

Control Software Features

Make sure that the system is fully assembled and all electrical connections to the control unit are properly made. The control computer is connected to the electronic control unit via a USB cable. System should be degassed and leak checked (refer to the appropriate section of the manual). Turn on electronic control unit and vacuum pump.

Start the software by double clicking the “Savannah 200” program icon. If running LabView version of the software press run button (white arrow) in the top left corner (arrow turns black once the program is running). Do not run the program with USB cable disconnected. This subsection describes the main features of Savannah 200 control software. The control program allows the operator to control the solenoid valves, pumping system, heaters, and to set deposition recipes. Buttons:

Program – stops the program

Vacuum Valve – operates stop valve to evacuate the reactor

Vent Valve – operates vent valve to vent system

All Heaters – turns ON/OFF all heaters Note: Make sure that that there is no run in progress before stopping

the program. Abort run first if necessary, then press Stop. Do not close window of the program while it is running.


22

Run Cycle Area:

Cycle Matrix –allows programming of a cycle sequence (recipe). The number of steps can be changed by toggling the upper left arrows (arrows are disabled during run). The active step is indicated in blue. The valve number is 0-5, depending on which valves have been connected. The pulse duration can be set between 0.0001 and 1.31 sec, however, the valves only start pulsing for t>0.007 sec. Expo indicates the exposure time. If Expo>0, the stop valve will close before the precursor valve pulses, and the stop valve opens again Expo seconds after the pulse valve has closed. With Expo=0, the stop valve will remain open during the step. The pumping time Pump (s) controls the pumping time between the pulses.

Cycles – programmed number of cycles with current cycle number displayed underneath.

Flow – sets inert gas (i.e. nitrogen) flow through the mass flow controller (MFC) with actual measured flow indicator under it. Flow can be changed during a run. Setting the flow to 10 sccm is usually sufficient for most processes. Make sure that two-port, not three-port, valves are being used if no carrier gas is required for the process.

Delay - time delay before start of the run (this is used to degas the sample or system or for temperature stabilization).

Close Stop Valve After Run – check this box to close stop valve after the run is finished. Can be used to vent the system automatically with carrier gas.

Runtime – time elapsed from the beginning of current run.

Save Run – check this box to save the run data into a file.

Start/Interrupt Run – starts or aborts current run.


23

Reactor Pressure Plot Area:

This plot tracks the reactor pressure read by the pressure gauge installed in the pumping line assembly. Pulses of the precursors are

clearly seen on the plot. Time scale can be reset by pressing Reset

Time button.

Heaters Control Area: This section of the program window controls temperature of the heaters. Temperature can be set by typing in values into light blue areas. Current temperature reading is indicated in the red area of each heater (under the set point area).


24

Venting the System

Degassing the System

It is recommended that the system is vented by closing the Vacuum

Valve (reactor is isolated from the pump) and filling the reactor with carrier gas. For faster venting higher flow can be set via mass flow controller (100 sccm). Vent valve can be removed and replaced with a blank flange. When no carrier gas is connected, system can be vented by opening

Vent Valve after Vacuum Valve has been closed. After venting, the vent valve will close automatically after 5 seconds. This method can cause back-streaming of the deposits from the pumping line into the reactor and might lead to contamination of the sample. Regular cleaning can reduce formation of the particles and flaking.

Before using the system for the first time after the installation or when new connections or precursors have been added or replaced, the system has to be degassed and checked for leaks.

Power up the system and evacuate the reactor (Vacuum Valve is opened). Set solenoid valve heaters to 60

oC, 4 way cross and

bellows heaters to 160 oC, and the inner and outer reactor heaters to

200 oC. Wait until temperature reaches set point for each heater. Note

the base pressure of the system. Degas the water cylinder by doing a run with at least 50 cycles, valve

0 Pulse time of 1.2 seconds, and the Pump time set around 3

seconds. The Flow should be set to zero.


25

After the water source degassing run is done and the temperatures have stabilized note the base pressure of the system. Degas the headspace between the solenoid and manual valve of the second precursor by doing the following. Keeping the manual valve on the precursor (trimethylaluminum in this example) still closed do a run

with valve 1 opening for a 1.2 second Pulse time. The Pump time is

again around 3 seconds and the Flow is 0 sccm.

When the base pressure during this run is the same as the base pressure of the system then this area has been degassed. Degas the headspace of atmospheric gases before opening the manual valve every time the space between manual and solenoid valves has been exposed to air. Also degas this area after closing the manual valve if the solenoid valve is to be removed.


26

Loading/Unloading the

Sample

Performing a Growth Run

To load/unload the sample vent the reactor (refer to Venting section of the manual). Once the reactor is at atmospheric pressure, open the lid and place the sample into recessed area in the center of the reactor. Close the lid and evacuate the system. ALD growth of Al2O3 is used to demonstrate a deposition procedure. After system has been degassed and vented:

Load the sample

Pump down the reactor

Make sure that Cycle Matrix has two rows available for water and TMA valves

For valves 0 and 1 set Pulse time to 0.025 sec, Expo time – 0

sec, Pump time – 10 sec

Set number of Cycles to 300, carrier gas Flow to 10 sccm

Delay time is set 10 min to provide enough time for pre-run pump down and temperature stabilization.

Check Save Run box to save run data.

Press Start Run button.

In this example about 30 nm of aluminum oxide is deposited. This thickness is almost invisible to the eye, but if the wafer is turned over an “ALD frame” can be seen on the backside of the wafer.


27

Use of Expo

Exposure mode can be used for the coating of ultra high aspect ratio

structures. In the following screen shot Pulse time for both valves is

set to 1.2 seconds. Expo time is set to 30 seconds. During this time (exposure) the stop valve is closed to allow current precursor to fully

react with the surface of the sample. Pump time is set to 240 seconds to provide sufficient time for removal of unreacted precursor and reaction byproducts. It is recommended to use little or no carrier gas for the process of this type. In this example, 10 sccm was used. This example is only used to illustrate the principle of using the stop valve during a run.


28

Multidosing If more dose of a single precursor is needed, multidosing can be used

instead of or in addition to using Expo. The following screenshot of multidosing illustrates that each valve can be pulsed multiple times for varying amounts of time and each valve can have different pumping times. In this example valve 0 is first pulsed for 0.01 s, with a pump (purge) time of 1 second, after which it is pulsed again for 0.5 seconds. After the second pulse the pump time is 15 seconds. Then valve 1, pulses for 0.01 seconds after which 10 seconds of pump time is used before the cycle repeats.

Part 2: Basic growth process

Cambridge NanoTech ALD System – User Instructions

This is a shortened version that focuses mainly on the operation. For more detailed instructions, please refer to the user manual “Cambridge NanoTech Savannah 100 Atomic Layer Deposition System” available both on-line and near the ALD setup.

System description Atomic layer deposition (ALD) is a technique that allows growth of thin films with atomic layer precision. The ALD system in PRISM clean room is designated for growth of Al2O3 film, which uses water and trimethylaluminum (TMA) as precursors. ALD is a self-limiting process so each cycle produces exactly a monolayer with a maximum of 1.1Å of Al2O3 depending on the temperature. Before starting: Important notes

• TMA is pyrophoric and ignites when in contact with the air. Never remove TMA source.

• The chamber lid and the walls are HOT! Use care when opening the chamber. Do not place any flammable materials on or near the ALD machine.

• The chamber lid cannot be lifted if the chamber is cold. The temperature of the chamber outer heater should be set to at least 80ºC.

• Do not put in materials that will outgas. Do not use a substrate having carbon tape. Do not use vacuum grease on your substrate or in the chamber.

• System is intended to have the pump running, nitrogen flowing, and heaters on at all times, even when idle.

• If restarting the system after it has been cold, e.g. following a power outage or maintenance shutdown, warm up the system first and follow the out-gassing procedure completely as described in the system manual. If you are not sure, contact Helena, Joe or one of the superusers to restart the system.

• In case that either of the precursors is running out, indicated by the disappearance of pulses during the running cycles, contact Helena, Joe or one of the superusers for replacement. Do not attempt to change precursors by yourself.

• The largest wafer size supported is 4” circular.

• Always set the center heater to 150ºC and the outer heater to 150ºC after you finish the growth.

1

Software user interface Buttons:

Program ⎯ Stop the Labview program Stop Valve ⎯ Open and close the stop valve to the pump All heaters ⎯ Turns all the heaters ON/OFF

Run cycle area:

Cycle matrix ⎯ Programming of the cycle recipe. Valve indicates the source valve to be opened. Valve 0 connects to the DI water precursor, and 1 to the TMA precursor. Pulse sets the time for which the source valve is opened. Valves only respond to pulsing for t>0.007 sec. Expo gives the time for which the stop valve is closed after pulsing the source and before pumping the chamber. See exposure mode below. Pump sets the time between the pulses of each source, in which the chamber is pumped and vapor removed. This should be long enough so that the chamber reaches base pressure before next pulse.

Cycles ⎯ Programmed number of cycles. The current cycle number is displayed underneath.

Flow ⎯ Sets the flow rate of carrier gas (here nitrogen with ultra-low water content) as controlled by MFC.

Delay ⎯ Time delay before the start of a run. Usually set for temperature stabilization.

Save Run ⎯ Check the box to save the run data in the file described below.

Run Time ⎯ Calculated total time for the current run.

2

Start/Abort Run ⎯ Start or abort the current run. The arrow turns bright green as run starts and gray green as it stops.

Reactor Pressure Plot Area:

This plot tracks the reactor pressure read by the gauge installed in the pumping line assembly. Pulses can be seen on the plot. Time scale can be reset by Reset Time.

Heaters control Area: Control the temperature of the heaters. Temperatures can be set by typing values into the light blue areas. The current temperature readings are indicated in the red area of each heater under the set point. Heater settings: Maximum / Recommended (°C) Solenoid valve ⎯ 115 / 80 Center heater ⎯ 400 / 250-300 Outer heater ⎯ 200 / 150 (80 minimum) Tee and elbow ⎯ 180 / 150 Pumping line ⎯ 180 / 150

3

Operating Instructions: Load/Unload

1. Close the stop valve and set the flow rate to 100 sccm to vent the chamber. Only vent when system hot (chamber >60°C). Leave system vented for as short a time as possible.

2. Wait for the lid to rise slightly from the chamber. Please be patient, it is important to wait for the chamber to reach atmospheric pressure to preserve the integrity of the O-ring.

3. Lift the lid and place your sample in the center of the chamber. Close the lid. 4. Open the stop valve to pump down the chamber. The base pressure should be less than 1

Torr, depending on the flow rate. Growth run ⎯ Continuous flow mode (recommended)

1. Pump down the reactor chamber by opening the stop valve after loading sample. 2. Make sure all heaters are set to the desired temperatures. 3. Enter the desired values for cycle parameters. A typical recipe is below. This recipe

below will give you 300 monolayers (approx. 33 nm) of Al2O3.

Valve Pulse (s) Expo (s) Pump (s) Cycles Flow (sccm) Delay (min) 0 0.07 0 4 300 20 0 1 0.07 0 4

4. Click Start run in the run cycle area. You can see the pulses in the pressure plot area. 5. After the run is over, vent the system and remove your sample. Close the lid and pump

down with flow rate set to 20 sccm. Let the system idle. Growth run ⎯ Exposure mode Exposure mode can be used for the ultra high aspect ratio structures. A typical recipe is listed below. For both valves, Pulse sets to 0.2 sec; Expo sets to 4 sec to allow fully reaction of the current precursor with the sample surface; Pump sets to 10 sec to provide sufficient time to remove any un-reacted precursor and/or by products. Carrier gas is recommended and Flow can use 5sccm. Degassing (only after installation of precursors or system checked for leaks) Water cylinder ⎯ Valve 0, Pulse = 1.3, Expo = 0, Pump = 3, Cycle = 5, Flow = 5 TMA cylinder ⎯ Valve 1, Pulse = 1.3, Expo = 0, Pump = 3, Cycle = 5, Flow = 5 Keep the manual valve of TMA source still closed while degassing. Degassing is essential every time the space between manual and solenoid valves is open to air.

4

Part 3: Official training tutorial from Manufacturer.

www.cambridgenanotech.com www.cambridgenanotech.com 11

Atomic Layer Deposition

A Tutorial by Cambridge NanoTech Inc.Cambridge, MA 02139 USA

Contact us to receive the Powerpoint version!

Cambridge NanoTech Inc. 23 Perry Street, Cambridge MA 02139 USAOffice:+1-617-233-8934 Lab:+1-617-251-6639 Fax:+1-509-479-0343

E-mail: [email protected]

http://www.cambridgenanotech.com/

mailto:[email protected]


About Atomic Layer Deposition (ALD)About Atomic Layer Deposition (ALD)

Atomic Layer Deposition (ALD) is used to deposit thin films with special qualities.

The principle of ALD is based on sequential pulsing of chemical precursor vapors, both of which form about one atomic layer each pulse. This generates pinhole free coatings that are extremely uniform in thickness, even deep inside pores, trenches and cavities.

100 nm Al2

O3

coating on Si wafer.


Cambridge Cambridge NanoTechNanoTech

Inc. ALD systemsInc. ALD systems

The Cambridge NanoTech Inc. Atomic layer deposition systems are controlled with a convenient Labview-PC-USB interface.

They are hot wall ALD systems with cross flow travelling wave precursor deposition. Nitrogen carrier gas is used for high speed pulse-purge cycles.

Prior to deposition, a substrate is inserted into the ALD reactor,and is heated usually between 50-400°C

2005 © All rights reservedCambridge NanoTech Inc.


ALD example cycle for AlALD example cycle for Al22

OO33

depositiondeposition

In air H2 O vapor is adsorbed on most surfaces, forming a hydroxyl group. With silicon this forms: Si-O-H (s)

After placing the substrate in the reactor, Trimethyl Aluminum (TMA) is pulsed into the reaction chamber.

Tri-methylaluminumAl(CH3 )3(g)

CH

HH

H

Al

O

Hydroxyl (OH)from surfaceadsorbed H2 O

Methyl group(CH3 )

Substrate surface (e.g. Si)



ALD cycle for AlALD cycle for Al22

OO33

Al(CH3 )3 (g) + : Si-O-H (s) :Si-O-Al(CH3 )2 (s) + CH4

Trimethyl Aluminum (TMA) reacts with the adsorbed hydroxyl groups,producing methane as the reaction product

C

H

H

H

H

Al

O

Reaction ofTMA with OH

Methane reactionproduct CH4

H

HH

HH C

C





OO33

C

HH

Al

O

Excess TMA Methane reactionproduct CH4

HH C

Trimethyl Aluminum (TMA) reacts with the adsorbed hydroxyl groups,until the surface is passivated. TMA does not react with itself, terminating the

reaction to one layer. This causes the perfect uniformity of ALD.The excess TMA is pumped away with the methane reaction product.





OO33

C

HH

Al

O

H2 O

HH C

OHH

After the TMA and methane reaction product is pumped away, water vapor (H2 O) is pulsed into the reaction chamber.




OO33

2 H2 O (g) + :Si-O-Al(CH3 )2 (s) :Si-O-Al(OH)2 (s) + 2 CH4

H

Al

O

O

H2 O reacts with the dangling methyl groups on the new surface forming aluminum- oxygen (Al-O) bridges and hydroxyl surface groups, waiting for a new TMA pulse.

Again metane is the reaction product.

O

Al Al

New hydroxyl group

Oxygen bridges

Methane reaction product

Methane reaction product




OO33

H

Al

O

O

The reaction product methane is pumped away. Excess H2 O vapor does not react with the hydroxyl surface groups, again causing perfect passivation to one atomic layer.

O O

Al Al




OO33

One TMA and one H2 O vapor pulse form one cycle. Here three cycles are shown, with approximately 1 Angstrom per cycle. Each cycle including pulsing and pumping takes e.g. 3 sec.

O

H

Al Al Al

HH

OO

O OO OO

Al Al AlO O

O OO

Al Al AlO O

O OO

Al(CH3 )3 (g) + :Al-O-H (s) :Al-O-Al(CH3 )2 (s) + CH4

2 H2 O (g) + :O-Al(CH3 )2 (s) :Al-O-Al(OH)2 (s) + 2 CH4

Two reaction steps in each cycle:




OO33

The saturative chemisorption of each layer and its subsequent monolayerpassivation in each cycle, allows excellent uniformity into high aspect ratio 3D structures,

such as DRAM trenches, MEMS devices, around particles etc.



Animation of the ALD process!

see our website

http://www.cambridgenanotech.com/animation


ALD DepositionALD Deposition

advantagesadvantages

Digital thickness control to atomic level.3D conformality (100% step coverage).Large area uniformity.Easy batch scalability (small material sources and substrate stacking).Pinhole free films, even over very large areas.Excellent repeatability (wide process window).Low defect density.Excellent adhesion due to chemical bonds at the first layer.Nanolaminates and mixed oxides possible.Gentle deposition process for sensitive substrates, no plasma.Low temperature deposition possible (RT-400C).Atomically flat and smooth, copies shape of substrate perfectly.Low stress because of molecular self assembly.100% dense guarantee ideal material properties (n, Ebd, k, etc).Relatively insensitive to dust.Oxides, nitrides, metals, semiconductors possible (standard recipes).Amorphous or crystalline depending on substrate and temperature.Coats on everything, even on teflon.Higher yields

- Not all materials possible yet

Alternating reactant exposure creates unique properties of deposited coatings:


Thin film deposition methods comparedThin film deposition methods compared

MethodMethod ALDALD MBEMBE CVDCVD SputterSputter EvaporEvapor PLDPLD

Thickness UniformityThickness Uniformity goodgood fairfair goodgood goodgood fairfair fairfairFilm DensityFilm Density goodgood goodgood goodgood goodgood poorpoor goodgoodStep CoverageStep Coverage goodgood poorpoor variesvaries poorpoor poorpoor poorpoorInterface QualityInterface Quality goodgood goodgood variesvaries poorpoor goodgood variesvariesNumber of MaterialsNumber of Materials fairfair goodgood poorpoor goodgood fairfair poorpoorLow Temp. DepositionLow Temp. Deposition goodgood goodgood variesvaries goodgood goodgood goodgoodDeposition RateDeposition Rate fairfair poorpoor goodgood goodgood goodgood goodgoodIndustrial ApplicabilityIndustrial Applicability goodgood fairfair goodgood goodgood goodgood poorpoor

ALD = atomic layer deposition, MBE = molecular beam epitaxy.CVD = chemical vapor deposition, PLD = pulsed laser deposition.



Sigma Aldrich is our exclusive partner forprecursor chemicals and supplies this list of ALDprecursors, preloaded in Cambridge NanoTechcylinders, ready to mount toour ALD systems. Simplyorder online!

Cambridge Nanotech provides recipes to growmany of these materials.

Chemfiles


Our ALD products

see also:

http://www.cambridgenanotech.com/Products/products.php


SavannahSavannah

100 & 200 ALD100 & 200 ALD

Travelling wave cross flow reactorAffordable for research labsExpandable (ozone, plasma, analytical systems)Small footprint (19 x 22 inches)Savannah Savannah 100 & 200100 & 200 Technical specificationsTechnical specifications

Substrate SizeSubstrate Size up to up to 200200 mmmm

Substrate TemperatureSubstrate Temperature 2525°°C C –– 500500°°CC; ; ±±0.20.2°°C C

Precursor SourcesPrecursor Sources Up to 6, heated.Up to 6, heated.

Deposition UniformityDeposition Uniformity <<±±1% 1%

FootprintFootprint 550550 x 550 mmx 550 mm

DepositionDeposition High speed/ultra high High speed/ultra high aspect ratio aspect ratio

ControlControl LabviewLabview--USBUSB--PCPC

Vacuum PumpVacuum Pump IntegratedIntegrated

CompatibilityCompatibility CleanroomCleanroom Class 100Class 100

CabinetCabinet Removable panelsRemovable panels

PowerPower 115Vac or 220Vac, 900W.115Vac or 220Vac, 900W.

OptionalOptional Domed lid for batchesDomed lid for batches

OptionalOptional Any substrate sizeAny substrate size

OptionalOptional Full custom designFull custom design


Email received from Prof. Marek Godlewski PAS Poland:

We are very happy with the new ALD system SAVANNAH 100, which we

bought from Cambridge NanoTech Inc. We have grown more than 100 samples within the first 5 months after the purchase of this ALD system and the system worked perfectly. Presently we work on thin films of ZnO and ZnMnO, the first material for new electronics applications, the latter material for spintronics applications. It turned out to be very crucial to grow ZnO and ZnMnO at very low temperatures. In the case of ZnMnO we could avoid so-called spinodal decomposition and also accumulation of foreign Mn oxide phases. The obtained material was very homogeneous showing

preferential magnetic properties.

From Marcello Zucca, Laboratorio di Chimica per le Tecnologie Università

di Brescia, Italy

ALD system of Cambridge Nanotech is a perfect instrument to deposit nanometric films of metal oxides. The instrument is very reliable and thanks to interface it's very easy to use.

We are able to deposit without problems titanium and zinc oxide

and soon other oxides. We have obtained great results also thanks to

the constant support of cambridge Nanotech. The customer assistance has always been helpful, fast and kind.

Email received from customer Dr. Thomas W. Scharf:

"UNT is using the Cambridge NanoTech ALD system to deposit solid

lubricant and nanocrystalline lubricous oxides for moving mechanical assembly (MMA) applications, such as fully assembled, miniature steel rolling element bearings and silicon MEMS. UNT is very happy with the system, technical support, ALD expertise and timeliness in responses from Cambridge NanoTech."

Professor Goldhaber-Gordon from Stanford University wrote:

The ALD system runs smoothly, producing conformal, high-breakdown aluminum oxide on a variety of substrates (we'll soon try depositing other materials). Cambridge Nanotech support is great --

they always respond to technical questions very fast and give useful suggestions.

From Old Dominion University, Prof. Baumgart:

One of my students " Kanda Tapily " enjoyed numerous helpful contacts with you and appreciates your valued technical advise on whatever issues and questions did arise during his work. The Cambridge Nanotech ALD system works really fine and we are very happy about the tool. This ALD tool can be easily managed by graduate students in a university environment and works like a charm.

From a customer who asked their startup company is not mentioned:

"Cambridge NanoTech has been most excellent to provide expertise

and starting points for developing processes to push our technology to the next level. Their customer support is excellent. We've been using the Savannah system to grow films from the first day it was installed."

CNT Customer testimonials:CNT Customer testimonials:


Applications: HighApplications: High--k dielectrics for CMOSk dielectrics for CMOS

Silicon subsrate

Source Drain

Gate

Gate oxide

channel

2000 2005 2010 2015

1

10

100

year

Leng

th (n

m)

N ode

G ate length

E O T

Si atom diam eter

Smaller transistors => short channel effectNeed stronger electrostatic coupling of gate =>Thinner gate dielectrics but SiO2 tunneling current => high-k dielectrics

Intel 2007 production in 45 nm chips!


5 conditions -•

High enough dielectric constant k•

Stable -

no reaction with Si•

Oxides with high heat of formation•

Preferred –

HfO2

, Zr, Y, La, Al

•

Stable up to 10500C•

Low diffusion, amorphous HfSiOx

:N•

Wide band gap for low leakage•

Good interface, low impurities, traps

0 10 20 30 40 50 602

3

4

5

6

7

8

9

10

KB

and

Gap

(eV) MgO

BaOSrO

CaO

SiO2Al O2 3

ZrO2HfO2

TiO2

ZrSiO4HfSiO4

Si N3 4Ta O2 5

La O2 3

Y O2 3

Choice of highChoice of high--k dielectric materialk dielectric material

Source: J. Robertson


Applications: Semiconductor memoryApplications: Semiconductor memory

SiO2

Dielectric

Top electrode

poly Si

Hausmann et al. Thin Solid films 2003.

3D DRAM needs conformal coatingof high-k dielectric and metal electrode

C=kA/d: Al2O3, ZrO2, Ta2O5DRAM crownDRAM trench

Samsung uses ALD for DRAM manufacture!

High aspect ratio ALDof Ta2O5 in vias of 170 nm dia, 7 micronsdeep

100 nm

100 nm


Applications: Applications: Gate dielectrics on nonGate dielectrics on non--Si devicesSi devices

(a) Schematic of finger gated devices. Mo gates (150nm wide 10 nm thick) were defined lithographically on a Si/SiO2 substrate and subsequently coated with 25 nm of HfO2 grown by low-temperature ALD. Nanotubes were grown across these local gates by CVD and contacted with Ti/Au electrodes. Not to scale.

(b) Atomic force micrograph of nanotubes grown across Mo finger gates and contacted (far left and far right) by Ti/Au leads. Note that one finger gate passes directly underneath the nanotube-metal contact. Arrows indicate the location of the nanotube. Finger gates are labeled as in the text.

Local gating of carbon nanotubes, Biercuk, Nano Letters 2003

Cambridge NanoTech Client: Prof. C.M. Marcus, Harvard University.


Applications: ALD liftoffApplications: ALD liftoff

Low-temperature atomic-layer-deposition lift-off method for microelectronic and nanoelectronic

applications, Biercuk, APL 2003.




Cambridge Nanotech Client: Nobel laureate Prof. Tsui, Princeton University



Cambridge Nanotech Client: Prof. Ohno, Tohoku University, Japan.


Applications: Applications: ALD liftALD lift--off technologyoff technologyCambridge NanoTech Client: C.M. Marcus, Harvard University.

Cambridge NanoTech co-authored publication,Applied Physics Letters

2003.


WN WN metal barriermetal barrier

for Cu interconnectsfor Cu interconnects

• Prevents Cu diffusion into silicon• Refractory nature• Amorphous• Acts as an adhesion promotor for Cu and Co

33 nm

32 nm

Top

Bottom

ALD Tungsten nitride (WN)

Cambridge NanoTech co-authored publication


Applications: Porous structuresApplications: Porous structures

Atomic Layer Deposition in Porous Alumina (Top view)

13 nm

21 nm

13nm

Top View after deposition

Al2 O3

Al

View

Reference SampleDP =35..45 nm

24 nm

K. Nielsch, Max Planck Institute, 2004


Before deposition

Cambridge NanoTech Client: K. Nielsch, Max Planck Germany



Atomic Layer Deposition in Porous Alumina (Bottom view)

9 nm

13 nm16 nm

Bottom View after deposition

Al2 O3

Al

View

Reference SampleDP =35..45 nm


Before deposition

Uniform deposition into 40 nm holes 50 μm deep>1:1250 aspect ratio!




TiO2

-Al2

O3

-TiO2

coaxial nanotubes grown with ALD inside porous alumina.




Applications: Applications: ferromagnetsferromagnets

Nickel nanotubes grown in porous alumina, then alumina etched away




Applications: Applications: Nanotube formationNanotube formation

Nature Materials 2007 Published online: 2 July 2006; doi:10.1038/nmat1673

cambridge NanoTech Client: K. Nielsch, Max Planck Germany


PlayPlay--LD:LD:

coating of viruscoating of virus

Deposition of Al2

O3

inside and around tubular shaped tobacco mozaic virus length 300 nm, OD 18 nm, ID 4 nm. Grown < 80C

cambridge NanoTech Client: K. Nielsch, Max Planck Germany


PlayPlay--LD:LD:

butterfly PC waveguidebutterfly PC waveguide

Morpho Peleides butterfly Wing photonic latticeCambridge NanoTech Client: Zhong Lin Wang, Georgiatech.


PlayPlay--LD:LD:

butterfly PC waveguidebutterfly PC waveguide

Cambridge NanoTech Client: Zhong Lin Wang, Georgiatech.


Applications: Applications: AntiAnti--reflection coatingsreflection coatings

Zaitsu et al. Applied Phyics Letters, 80, 2442, 2002

ALD good for AR coatings: large area precision thickness control and batch coating.

=> Graded index coatings posssible by varying the number of Al2O3/TiO2 low n/high n layers inside a nanolaminate stack


Applications: Applications: Transparent conductorsTransparent conductors

ALD-ZnO transparent conductors advantages:

No costly indium as in ITOGood optical transmission Low resistivity (1 mOhmcm)Large area uniformityVery smooth films in contrast to ITO

Thin film transistors:

ALD of ZnO active matrix thin filmtransistors possible as well.


Applications: Applications: humidity barriershumidity barriers

Water vapor transmission rate of 25 nm ALD Al2O3 better than 1 mm polymer encapsulation!

WVTR <10−5 g/m2

day demonstrated

Applied Physics Letters, 89, 031915 2006


For more applications see:

http://www.cambridgenanotech.com/ALD-applications.php

and

http://www.cambridgenanotech.com/clientmap/clientpapers.php


Our websiteOur website

More ALD applicationsCustomer ALD networkTutorial, animationALD literature search pageProduct informationContact information

Lots of information

www.cambridgenanotech.com

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