![Page 1: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/1.jpg)
Xing Sheng, EE@Tsinghua
1
Xing Sheng盛兴
Department of Electronic EngineeringTsinghua University
Film DepositionPart IV: CVD
Principles of Micro- and Nanofabrication for Electronic and Photonic Devices
![Page 2: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/2.jpg)
Xing Sheng, EE@Tsinghua
4
Film Deposition
PVD: Physical Vapor DepositionCVD: Chemical Vapor Deposition
![Page 3: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/3.jpg)
Xing Sheng, EE@Tsinghua
5
Film Deposition
PVD: Physical Vapor DepositionCVD: Chemical Vapor Deposition
![Page 4: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/4.jpg)
Xing Sheng, EE@Tsinghua
CVD Si
poly-Si
W, SiO2, ...
PVD Al, Ti
...
Electrodeposition Cu
6
Thin Film in CMOS
![Page 5: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/5.jpg)
Xing Sheng, EE@Tsinghua
APCVD Atmosphere Pressure CVD
LPCVD Low Pressure CVD
UHVCVD Ultrahigh Vacuum CVD
MOCVD Metal Organic CVD
PECVD Plasma Enhanced CVD
ALD Atomic Layer Deposition
...
CVD: Chemical Vapor Deposition
7
![Page 6: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/6.jpg)
Xing Sheng, EE@Tsinghua
Example:
CVD: Chemical Vapor Deposition
8
SiH4 (g) = Si (s) + 2H2 (g)
SiH4 (g) + O2 (g) = SiO2 (s) + 2H2 (g)
![Page 7: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/7.jpg)
Xing Sheng, EE@Tsinghua
CVD
9
Process Parameters Time
Temperature
Gas type
Gas pressure
Flow rate
...
Control Parameters Film thickness
Crystallinity
Film quality (defects, dielectric strength, ...)
- gas transport- surface reaction
Q: differences between CVD and oxidation?
![Page 8: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/8.jpg)
Xing Sheng, EE@Tsinghua
Crystallinity
10
temperature
deposition rate
Deposit Si on Si
Monocrystalline Polycrystalline Amorphous
SiH4 (g) = Si (s) + 2H2 (g)
800 oC 600 oC
![Page 9: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/9.jpg)
Xing Sheng, EE@Tsinghua
Crystallinity
11
temperature
efficiency
Silicon Solar Cells
Monocrystalline Polycrystalline Amorphous
price
![Page 10: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/10.jpg)
Xing Sheng, EE@Tsinghua
Deposition Rate vs. Temperature
12
2/3~ TR
kT
ER exp~
![Page 11: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/11.jpg)
Xing Sheng, EE@Tsinghua
Deposition Rate vs. Gas Flow
13
![Page 12: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/12.jpg)
Xing Sheng, EE@Tsinghua
Issues of Gas Transport
14tilt the samples to improve uniformity
![Page 13: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/13.jpg)
Xing Sheng, EE@Tsinghua
Issues of Gas Transport
15
better to operate at surface reaction limited zone(low T, high flux rate)
![Page 14: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/14.jpg)
Xing Sheng, EE@Tsinghua
Gas Types
16
Si CVD
![Page 15: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/15.jpg)
Xing Sheng, EE@Tsinghua
LPCVD
17
Low Pressure CVD at low pressure,
- Increased rate- Increased zone for surface reaction- reduce cost
why ??
![Page 16: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/16.jpg)
Xing Sheng, EE@Tsinghua
LPCVD
18
Low Pressure CVD
pr
kT22
molecular mean free path
p
![Page 17: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/17.jpg)
Xing Sheng, EE@Tsinghua
PECVD
19
Plasma Enhanced CVD
plasma enhances the ion energy:
- higher dep. rate- lower temperature
![Page 18: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/18.jpg)
Xing Sheng, EE@Tsinghua
SiO2 Growth Methods
20
dry oxidation
Si + O2 ~ 1100 oC
wet oxidation
Si + H2O ~ 1000 oC
APCVD / LPCVD
SiH4 + O2 400~600 oC
PECVD
SiH4 + N2O 200~400 oC
Sputter or Evaporation
substrate at room temperaturegrowth
temperaturefilm
quality
![Page 19: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/19.jpg)
Xing Sheng, EE@Tsinghua
Step Coverage
21
surface reaction controlled diffusion/transport controlled
- LPCVD, UHVCVD, oxidation- ALD- ...
- PECVD- PVD (sputter, evaporation)- ...
![Page 20: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/20.jpg)
Xing Sheng, EE@Tsinghua
MOCVD
22
Metal-Organic CVD
Ga(CH3)3 (g) + AsH3 (g) = GaAs (s) + 3CH4 (g)
Ga(CH3)3 (g) + NH3 (g) = GaN (s) + 3CH4 (g)
![Page 21: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/21.jpg)
Xing Sheng, EE@Tsinghua
ALD: Atomic Layer Deposition
23
precursor
reactant
- self limited growth- layer by layer - high uniformity- accurate thickness control
2Al(CH3)3 + 3H2O = Al2O3 + 6CH4
Si(OCH2CH3)4 + H2O = SiO2 + ...
Hf(N(C2H5)(CH3))4 + H2O = HfO2 + ...
TiO2 / Al2O3 multilayer
![Page 22: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/22.jpg)
Xing Sheng, EE@Tsinghua
ALD: Atomic Layer Deposition
24
thickness t is already ~ nmhigh -> large C -> large ID
t
AC
VVC
L
WI thG
SatD
0
2
,2
)(
![Page 23: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/23.jpg)
Xing Sheng, EE@Tsinghua
Selective Deposition
25
non-selective (everywhere)
Tungsten (W) via by CVD
WF6 (g) + 3H2 (g) = W (s) + 6HF (g)
2WF6 (g) + 3Si (s) = 2W (s) + 3SiF4 (g)
selective, only on Si, not SiO2
Q: why do we use CVD for W vias?
![Page 24: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/24.jpg)
Xing Sheng, EE@Tsinghua
Step Coverage
26
surface reaction ballistic transport
![Page 25: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/25.jpg)
Xing Sheng, EE@Tsinghua
Localized CVD
27
higher T --> higher rate
B. Sosnowchik, et al., J. Appl. Phys. 107, 051101 (2010)heated region
![Page 26: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/26.jpg)
Xing Sheng, EE@Tsinghua
Graphene by CVD
28
Grephene likes to nucleate at Cu grain boundariesHow to get single crystal graphene?
![Page 27: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/27.jpg)
Xing Sheng, EE@Tsinghua
Graphene by CVD
29
Single Crystal Substrate
Single Crystal Graphene
X. Xu, et al., Science Bulletin 62, 1074 (2017)
![Page 28: Xing Sheng, EE@Tsinghua Principles of Micro-and ... · Xing Sheng, EE@Tsinghua 1 Xing Sheng盛兴 Department of Electronic Engineering Tsinghua University xingsheng@tsinghua.edu.cn](https://reader035.vdocuments.mx/reader035/viewer/2022062604/5fc534228376e7431b03a9c1/html5/thumbnails/28.jpg)
Xing Sheng, EE@Tsinghua
Diamond by CVD
30