Thermodynamic Behavior of SiH2Cl2 in Polysilicon Production by Siemens Process

Abstract

The present of SiH₂Cl₂ (DCS) is a big problem because of its instability. The content of SiH₂Cl₂ should be controlled below somewhat concentration. Therefore, the present study is aimed at investigating the thermodynamic behavior of SiH₂Cl₂ in polysilicon production by Siemens process in order to provide effective theory for the production process. The effect of pressure (1-5atm), feeding ratio of H₂ to SiHCl₃ (2-50) and temperature (1000-1500K) have been studied in the paper. The results show that the productivity ratio of DCS increases with increasing pressure and increases firstly and then decreases with increasing feeding ratio or temperature. In a word, the pressure have biggest effect on productivity ratio of DCS compared to temperature and feeding ratio.