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SIGE EPITAXY ON A 300 MM BATCH FURNACEAndreas Naumann1*, Jonas Sundqvist1, Marcel Ogiewa1, Laurent Boitier1, Malte Czernohorsky1, Stefan Sienz2, Guido Probst2, Bert Jongbloed3, Sjaak Beulens3 Steven van Aerde3, Jan Willem Maes3, Shawn Thomas4

1Fraunhofer-Center Nanoelektronische Technologien, Königsbrücker Str. 180, 01099 Dresden, Germany2ASM Germany Sales B.V., Peter-Henlein-Strasse 28, 85540 Haar, Germany, 3ASM Belgium, Kapeldreef 75, B-3001 Leuven, Belgium4 ASM America Inc., 3440 E. University Drive, Phoenix, Arizona 85034-7200, USA

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Table of Content

1. Fraunhofer CNT

2. SiGe Epitaxy on ASM A412 300mm Batch Furnace

3. Characterization Results

4. Summary

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The Heart of Microelectronics in Europe…

Area Dresden North

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Fraunhofer Center Nanoelectronic Technologies Docking Research into Manufacturing

800m2 Clean Room Area 200m2 Lab Area 40 Tools (Processing and

Metrology/Analytics)

External customers(IC manufacturers, Foundries)

Platform for material and process development on 300mm Si wafer

Short learning cycles Industrial-grade clean room

Infrastructure Linked to 300mm production

lines

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Table of Content

1. Fraunhofer CNT

2. Epitaxy on ASM A412 300mm Batch Furnace

3. Characterization Results

4. Summary

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Potential Batch Epi Applications

2011-09-20Confidential and Proprietary Information 6

S/D epi of cell transistor

PCRAM diode

Logic devices high mobility channel

(Selective) SiGe + Si

o (Selective) un-doped Ge

source-drain stressor w/ doping Un-doped Si, SiGe

o Doped Si, SiGe

o Complex S/D epi designs questionable

Memory DRAM peri source-drain stressor selective Si, SiGe

DRAM access transistor S/D epi selective Si

DRAM Bit Line Contact Selective SiGe

PCRAM Diode Selective Si

Solar Low cost of ownership solution

Blanket (selective) Si (B, P, As doped)

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Motivation for Large Batch Furnace Si, SiGe Epitaxy

Pro Reduced cost of ownership Less product sensitive Low temperature processing New applications (e.g. Solar)

Con Process development challenging Less flexibility (cycle time penalty)

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ASM A412 300mm Furnace @ Fraunhofer CNTProperties of A412 Batch Furnace:

Two reactors (TiN/TaCN + aSi, Poly, Si/SiGe EPI) Batch size up to 100 wafer (300mm) Inert minienvironment (< 10ppm O2) Internal stocker Atmospheric N2 loading ambient, i.e., no vacuum loadlock, which is more costly, complicated, and takes more (cycle) time.

Epitaxy Setup on Reactor1:

Max. temperature 900°C SiH4, GeH4, H2, N2, HCL available Base pressure <5 mTorr

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Target

Demonstrate Feasibility of Batch Furnace for SiGe Epitaxy.

Layer thickness 10 - 100 nm

Germanium concentration 10 - 45 at.%

Within wafer uniformity < 2% (1σ) (Ge concentration and layer thickness)

Oxygen background at interface below SIMS detection limit ( < 1E12 O/cm²)

Layer roughness < 0.2 nm RMS

Demonstrate SEG (25 at.%, 50 nm, selective to oxide and nitride)

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Table of Content

1. Fraunhofer CNT

2. Epitaxy on ASM A412 300mm Batch Furnace

3. Characterization Results

4. Summary

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Surface Cleaning

Clean conditions: HF last wet clean

Insitu clean with H2

Temperature 800°C

Low pressure

20 min

With 800°C bake:

Oxygen not detectable with ToFSIMS

0 200 400 600 800 10000

100

200

300

400

500

600

7000 25 50 75 100 125 150 175

Oxy

gen

Inte

nsity

[cts

/s]

Sputter time [s]

Oxygen [cts/s] 725°C Bake 775°C Bake 800°C Bake

Sputter depth [nm]

Oxygen free surface is a prerequisite for silicon epitaxy!

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Control of Layer Composition

SiGe composition tuneable with gas mixture

No penalty with layer properties

0

10

20

30

40

0 0.5 1 1.5 2

Germane flow [a.u.]

Ger

man

ium

con

cent

ratio

n [a

t.%]

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Layer Uniformity

Thickness: 50 nm, wiw 2.5% (1σ)Ge concentration: 25at.%, wiw 1.6% (1σ) Root cause gas depletion

1

23

4

56

7

8

9

1011

12

13

14

15

16

17 18 19

20

21

22

23

24

25

262728

29

30

31

32

33

34

35

3637 38 39

40

41

42

43

44

45

46

47

4849

-150 -100 -50 0 50 100 150

-150

-100

-50

0

50

100

150

SiGe layer thickness (Run60) [nm]

Y [m

m]

X [mm]

48,048,348,648,949,249,649,950,250,550,851,151,551,852,152,452,753,053,453,754,054,3

0 25 50 75 100 125 15046474849505152535455565758

Laye

r thi

ckne

ss [n

m]

Wafer radius [mm]

23

24

25

26

Ger

man

ium

Con

cent

ratio

n [a

t.%]

1

23

4

56

7

8

9

1011

12

13

14

15

16

17 18 19

20

21

22

23

24

25

262728

29

30

31

32

33

34

35

3637 38 39

40

41

42

43

44

45

46

47

4849

-150 -100 -50 0 50 100 150

-150

-100

-50

0

50

100

150

Ge concentration (Run60) [at.%]

Y [m

m]

X [mm]

23,623,723,823,823,924,024,124,124,224,324,424,424,524,624,724,824,824,925,025,125,1

Thickness [nm]

Ge concentration [at.%]

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Layer Roughness

Layer roughness similar compared to test wafer used. This example has a RMS of 0.17 nm

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Strain Analysis

Sharp SiGe peak and thickness fringes in ω-2θ-scan No offset between SiGe-224 and Si-224 in h-direction of RSM SiGe layer is fully strained

SiGe-224 Si-224

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Selective Epitaxial Growth (SEG) results

Silicon SEG with DCS+H2 @ 680°C

Selective to oxide

But unselective to nitride

Silicon nitride HM

SiGe SEG with SiH4+GeH4+HCl @520°C

Selective to oxide

Ge concentration not yet on target

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Table of Content

1. Fraunhofer CNT

2. Epitaxy on ASM A412 300mm Batch Furnace

3. Characterization results

4. Summary

© Fraunhofer CNT

March 17 2011 18

Rough throughput estimates

Process: SiGe (25 atm%), thickness <50 nm 100 wafer load

30 minutes boat-out, boat-in

60 minutes temperature ramp up, bake, cool down

< 30 minutes deposition

30 minutes overhead

Through put: >40 wafers/hour/chamber (>80 wafers/hour/tool)

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Summary

Accomplishments:Layer thickness 10 - 100 nmGermanium concentration 10 - 32 at.%Within wafer uniformity < 2.5% (1σ) (Ge concentration and layer thickness)Oxygen background at interface below SIMS detection limit ( < 1E12 O/cm²)Layer roughness < 0.2 nm RMSSi and SiGe grown selective to oxide

Further Investigation: Uniformity optimization SiGe SEG with nitride and oxide hard mask Improved epitaxial quality for selective growth Insitu doping (B, P) (started)

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Thank you !