Contribution to the modeling of CVD silicon carbide growth

The modeling of the growth of silicon carbide from the vapor phase in the Si-C-H system requires a good understanding of the gas-phase chemistry. The object of this paper is to complement the previous studies on the kinetic modeling of the gas-phase in the system SiH4 / C3H8. To date, kinetic approaches to modeling the gas-phase chemistry have not been fully developed Previous kinetic models have only dealt with the pyrolysis of individual precursors (silane and propane) without allowing for the formation of organosilicon species. This study provides a progress report on our efforts to develop a full gas-phase mechanism that includes organosilicon compounds. Rate constants for this mechanism are determined where possible from experimental data available in the literature. However, for several important reactions, experimental data are not available. Consequently, we are performing ab initio calculations to determine activation energies and are using RRKM calculations to estimate pressure fall-off effects for unimolecular reactions. In this contribution, we focus on the formation of methylsilane H3SiCH3 and discuss the importance ol: such species in the gas-phase chemistry of SiC deposition.