Analysis of Gaseous Species in Chemical Vapor Deposition of SiC from MTS/H2

Qualitative and quantitative analyses were carried out to investigate the effect of the deposition temperature, pressure and flow rate of chemical vapor deposition imposed on the concentrations of MTS/H2 CVD SiC gaseous species through GC/MS method. Decomposition procedures of MTS in H2 based on the reaction rate and concentrations of species were analyzed. The results show that: (1) the identified gaseous species are CH4 ￠C2H6 ￠C2H4, C3H6, C2H2, MTS, SiCl4 and CH3SiHCl2, of which the concentrations of CH4 and SiCl4 are comparatively higher; (2) temperature, pressure and flow rate have great effect on the concentrations of gaseous species, and their regular patterns follow the same dependence as the thermodynamics; (3) MTS mainly starts with the cracking and decomposition of Si-C, and experiences three stages, the reaction with H2, the formation of middle objects and also by-products. It is suggested that the main formation route of alkane is CH3 C2H6 C2H4 C2H2.