Thermodynamic Analysis on the Codeposition of SiC – Si ₃ N ₄ Composite Ceramics by Chemical Vapor Deposition using SiCl ₄ – NH ₃ – CH ₄ – H ₂ – Ar Mixture Gases

Abstract

A thermodynamic calculation on the chemical vapor deposition of the SiCl 4 – NH 3 – CH 4 – H 2 – Ar system was performed using the FactSage thermochemical software databases. Predominant condensed phases at equilibrium were SiC , Si 3 N 4 , graphite, and Si . The equilibrium conditions for the deposition of condensed phases in this system were determined as a function of the deposition temperature, dilution ratio (δ), and reactant ratios of CH 4 / SiCl 4 and NH 3 / SiCl 4 . The CVD phase diagrams were used to understand the reactions occurring during the formation of Si – C – N from the gas species and determine the area of SiC – Si 3 N 4 . The concentration of condensed‐phase products was used to determine the deposition conditions of CVD SiC – Si 3 N 4 . The present work was helpful for further experimental investigation on CVD Si – C – N .