Comparative study of the gas phase reaction of SiCl4, SiHCl3, SiH2Cl2, and SiH3Cl by thermodynamic analysis

Abstract Thermodynamic analyses based on first-principles calculations were performed for SiH x Cl 4−x (x = 0 ∼ 3) to compare the characteristics of these chlorosilanes. In the range of 600 °C–1100 °C, SiCl 4 almost does not decompose, while SiHCl 3 , SiH 2 Cl 2 , and SiH 3 Cl decompose and generate SiCl 2 as the main radical species. SiHCl 3 and SiH 2 Cl 2 have 3.8 and 4.5 times higher SiCl 2 equilibrium partial pressure than SiH 3 Cl at 600 °C, respectively. SiH 3 Cl has a lower equilibrium partial pressure of HCl than SiHCl 3 and SiH 2 Cl 2 by order level. Thus, it is expected that CVD using SiH 3 Cl gas is less affected by the HCl reaction.