Equilibrium prediction of the role of key species in the chemical vapor deposition of silicon carbide

Based on Gibbs minimum free energy principle, homogeneous equilibrium calculations were focused by Factsage code for MTS/H2 mixture. An assessment was made to determine the key species to SiC deposition. The results indicate that SiCl₂ and C₂H₂ may contribute to SiC deposition, and their formations are favored high temperature and low pressure. Most of silicon-containing and carbon-containing species are SiCl₄ and CH₄, at low temperature and high pressure. Other substances such as hydrocarbons, orgamosilicons and silane compounds are probably unimportant for deposition process because of their low concentrations and small surface reactive sticking coefficient. Silicon and carbon are formed independently, based on the fact that there are barely species containing Si-C and Si-Si in gas phase. The ratio of silicon and carbon in sample is determined by their kinetics, respectively.