Thermodynamics for the Chemical Vapor Deposition of SiCl₄-TiCl₄-CCl₄-H₂ System

Abstract

The thermodynamic calculations and the experimental results for the chemical vapor deposition of the Si-Ti-C-H-Cl system using SiCl₄, TiCl₄, CCl₄ and H₂ as source gases were compared. The thermodynamic calculations well explained the experimental results for the formation of such phases as the SiC+TiC, the SiC+TiC+C and the TiC+Ti₃SiO₂. The main gas species in equilibrium are (H₂), (HCl), (SiCl₂) and (TiCl₃). The equilibrium (H₂) and (HCl) partial pressures are almost independent of temperature. The equilibrium (SiCl₂) partial pressure increases with increasing temperature, and the equilibrium (TiCl₃)partial pressure decreases with increasing temperature. The theoretical deposition efficiency of ‹SiC› decreases with increasing temperature, and that of ‹TiC› increases with increasing temperature. The calculated compositions of SiC/(SiC+TiC) in the SiC+TiC phase were almost in agreement with the experimental values. The calculated compositions of SiC/(SiC+TiC) decrease with increasing temperature. However the experimentally obtained compositions increased with increasing temperature, which may be caused by the kinetic restriction for the formation of the ‹SiC› at lower deposition temperatures.