Equilibrium Computation for the Growth of Alpha Silicon Carbide from Silane and Propane in the Presence of Hydrogen or an Inert Gas

Abstract

The equilibrium computation for the growth of α-SiC from silane and propane in an atmosphere of hydrogen or an inert gas is carried out. The dependence of the deposition ratios of α-SiC, Si(l) and C(graphite) and the partial pressures of the vapor species on the concentration of the reactants and on the temperature is analyzed in detail. It is shown that in hydrogen atmosphere the deposition of α-SiC single phase occurs over a wide range of reactant partial pressures, i.e., from P(SiH₄)=3×P(C₃H₈) to a significant propane excess. In the presence of an inert gas this range is limited to the vicinity of P(SiH₄)=3×P(C₃H₈). This difference is apparently attributed to that the inert gas cannot remove the excess carbon into the vapor phase. Additional thermodynamic characteristics of these systems are also discussed.