Kinetics of halide chemical vapor deposition of silicon carbide film

Halide chemical vapor deposition (HCVD) emerges as a promising method for growing thick silicon carbide (SiC) epilayers, due to its ability to deposit SiC film at a high growth rate. In this paper, we develop a comprehensive model for HCVD of SiC film using silicon tetrachloride and propane as precursors. The model includes gas flow, heat and mass transfer, gas-phase reaction, and surface chemistry. Specifically, the gas-phase reactions and surface kinetics in the Si–C–Cl–H system are integrated into a transport process model to predict the composition of the gas mixture in the reactor and the deposition rate. The etching of graphite susceptor and SiC expitaxial layer are considered in the reaction mechanism. Simulations are performed in a horizontal hot wall reactor to provide information on the velocity, temperature, and concentration distributions of chemical species. The predicted deposition rates agree with experimental measurement documented in the literature. The graphite etching by hydrogen is shown to supply a substantial carbon source for the deposition, and is therefore of significant importance in determining the composition and chemical stoichiometry within the gas mixture. The modeling of surface kinetics identifies etching of the SiC layer by HCl as the leading process responsible for the reduced deposition rate at higher temperatures. The model developed can be further used for optimizing the system design and better controlling the SiC deposition process.