SiGe epitaxy on a 300 mm batch furnace, Presentation at The EuroCVD 18 conference will take place in Kinsale, County Cork, Ireland from the 4th – 9th September 2011

1. © Fraunhofer CNT
SIGE EPITAXY ON A 300 MM BATCH
FURNACE
Andreas 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, Germany
2ASM Germany Sales B.V., Peter-Henlein-Strasse 28, 85540 Haar, Germany, 3ASM Belgium, Kapeldreef 75, B-3001 Leuven, Belgium
4 ASM America Inc., 3440 E. University Drive, Phoenix, Arizona 85034-7200, USA

2. © Fraunhofer CNT
Table of Content
1. Fraunhofer CNT
2. SiGe Epitaxy on ASM A412 300mm Batch Furnace
3. Characterization Results
4. Summary

3. © Fraunhofer CNT
The Heart of Microelectronics in Europe…
Area Dresden North

4. © Fraunhofer CNT
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

5. © Fraunhofer CNT
Table of Content
1. Fraunhofer CNT
2. Epitaxy on ASM A412 300mm Batch Furnace
3. Characterization Results
4. Summary

6. © Fraunhofer CNT
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)

7. © Fraunhofer CNT
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)

8. © Fraunhofer CNT
ASM A412 300mm Furnace @ Fraunhofer CNT
Properties 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

9. © Fraunhofer CNT
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)

10. © Fraunhofer CNT
Table of Content
1. Fraunhofer CNT
2. Epitaxy on ASM A412 300mm Batch Furnace
3. Characterization Results
4. Summary

11. © Fraunhofer CNT
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 1000
0
100
200
300
400
500
600
700
0 25 50 75 100 125 150 175
OxygenIntensity[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.]
Germaniumconcentration[at.%]

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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
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
2627
28
29
30
31
32
33
34
35
36
37 38 39
40
41
42
43
44
45
46
47
48
49
-150 -100 -50 0 50 100 150
-150
-100
-50
0
50
100
150
SiGelayer thickness(Run60) [nm]
Y[mm]
X [mm]
48,0
48,3
48,6
48,9
49,2
49,6
49,9
50,2
50,5
50,8
51,1
51,5
51,8
52,1
52,4
52,7
53,0
53,4
53,7
54,0
54,3
0 25 50 75 100 125 150
46
47
48
49
50
51
52
53
54
55
56
57
58
Layerthickness[nm]
Wafer radius [mm]
23
24
25
26
GermaniumConcentration[at.%]
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
2627
28
29
30
31
32
33
34
35
36
37 38 39
40
41
42
43
44
45
46
47
48
49
-150 -100 -50 0 50 100 150
-150
-100
-50
0
50
100
150
Geconcentration(Run60) [at.%]
Y[mm]
X [mm]
23,6
23,7
23,8
23,8
23,9
24,0
24,1
24,1
24,2
24,3
24,4
24,4
24,5
24,6
24,7
24,8
24,8
24,9
25,0
25,1
25,1
Thickness [nm]
Ge concentration [at.%]

14. © Fraunhofer CNT
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

17. © Fraunhofer CNT
Table of Content
1. Fraunhofer CNT
2. Epitaxy on ASM A412 300mm Batch Furnace
3. Characterization results
4. Summary

18. © 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)

19. © Fraunhofer CNT
Summary
Accomplishments:
Layer thickness 10 - 100 nm
Germanium 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 RMS
Si 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 !