Reduction of chloro-silanes  (SiCl4,SiHCl3,SiH2Cl2, SiH4) at high temperature (~ 900 ℃ - 1150 ℃),H2 as reducing agent/ carrier gas and purge gas.  AsH3, B2H6, PH3 as dopant gas.  N2 as purge chamber and cool  wafer gas.  HCl as In-situ etching and cleaning chamber gas.

General reaction:

SiClx (gas)＋xH2(gas)<--->Si(solid)+2xHCl(gas)

SiCl4                 1150-1200℃

SiHCl3                 1130-1180℃

SiH2Cl2                       1050-1100℃

SiH4                 650-1000℃

Gas Character

Name	System	Temperature ( ℃ )	Deposit Rate ( um/min )	Advantage	Disadvantage
SiH4	Barrel System	900-1050	0.1-0.3	工艺温度低，无图形 漂移，washout小	生长速率低，石英件coating严重，对 O2 H2O 敏感，RP工艺中可操作性差
	Single System	950-1000	0.001-1.2
SiH2Cl2   (DCS)	Barrel System	950-1150	0.1-1.0	工艺温度低，适于RP 工艺	配管复杂，对温度波动敏感
	Single System	1050-1100	0.2-1.5
SiHCl3  (TCS)	Barrel System	1100-1200	1.0-3.0	生长速率高，纯度高	需要 H2 Bubbler
	Single System	1100-1190	1.0-4.0
SiCl4	Barrel System	1150-1230	0.4-1.0	生长速率较高，纯度高	需要 H2 Bubbler，工艺温度高

Process step 

P

Step	Purpose	Critical thing to be controlled
1.Purge	To purge out N2 gas that may come into chamber during wafer transfer-in	Removal of N2 before heating up
2.Temperature	To adjust parameters for H2 bake temperature /gas flow rates	Temperature ramp rate
3.H2 bake	To remove any remaining oxide on surface	Temperature stabilization
4.Etching	To adjust temperature / flow for deposition step	Quartz temperature Etching efficiency
5.Post Purge	To purge out HCI	Purge out HCI
6.Temperature ramp down	Target to coating temperature
7.Coat	To coat susceptor
8.Post purge	To purge out process gases out of the process chamber	Enough puring process gases with H2 and without temp/pressure change
9.Cool	To cool down to wafer transfer temp

Process Control 

1. slip line

2.Stacking Faults