The Advantages of the Schmid-Process
- Please click on the image for lager view
Schmid Silicon Technology (SST)
Single step catalytic disproportion of chlor silane mixture to monosilane and
pyrolysis of monosilan:
4 HSiCl3 = 3 SiCl4 + SiH4;
SiH4 = Si + 2 H2
Optimized total process structure in respect to: Hydrochlorination, Hydration, Disproportion and Pyrolysis
Siemens Prozess
Reduction of TCS with hydrogen:
HSiCl + H Si + 3
HSiCl3 H2 = HCl
- about 70 - 75% of worldwide poly silicon production
Advantages of the Schmid-Process
• Straight forward process structure simplifies operation
• Monosilane as produt for thin film industrie available
• No byproducts / vent gas generated in CVD
• No vent gas recovery system requested
• Hydrochlorination FBR comparable simple to start up and operate
• Hydrochlorination FBR incorporates both TCS processes (conversion and chlorination)
• No handling of HCL throughout the process structure
• Lower energy consumption due to lower temperatures in CVD and
overall process structure
• Higher yield up to 80%
• Disproportion step (TCS to monosilane) additionally removes impurities,
esp. Boron
