Thermodynamic calculations and kinetic verifications on the chemical vapor deposition process of Si–C–N ceramic from the SiCl3CH3–NH3–H2–Ar precursors

Abstract

Based on the Gibbs principle of minimum free energy and Factsage software, the thermodynamic phase diagram and three-dimensional yield map were firstly calculated from the SiCl3CH3–NH3–H2–Ar system. The effects of temperature, total pressure, reactant ratios of 3[NH3]/[SiCl3CH3] and [H2]/[SiCl3CH3] on the formation and yield of condensed phases were discussed. Predominant condensed phases at equilibrium were SiC, Si3N4 and graphite phases. The concentration of condensed phase products was used to confirm the composition of Si–C–N. Through the kinetic verification at 1173.15K, it could be demonstrated that Si–C–N ceramics are obtained by chemical vapor deposition from the SiCl3CH3–NH3–H2–Ar system. The deposits were amorphous and mainly constituted by C–C, Si–N and Si–C bonds from XPS analysis, which were well consistent with the results of thermodynamic calculation. The real part and the imaginary part of permittivity were approximately 4 and 0, respectively, which indicated the amorphous deposits possess the low dielectric constant and loss.