Finite element simulation of the effects of process parameters on deposition uniformity of chemical-vapor-deposited silicon carbide

A two-dimensional model was developed to simulate chemical vapor deposition process for preparing SiC coating by MTS + H₂ system in a vertical hot-wall reactor. The effects of process parameters, including deposition temperature, the flux of mixed gases, the ratio of H₂ and Ar, and the volume ratio of MTS and mixed gases, on deposition uniformity of SiC coating were calculated by finite-element method. The CVD process was optimized by an orthogonal L₉(3)⁴ test to deposit uniform SiC coating. The results show that the deposition uniformity of SiC is influenced greatly by the deposition temperature and the ratio of H₂ and Ar, and little by the flux of mixed gases and the volume ratio of MTS and mixed gases. The optimal deposition uniformity of SiC can be obtained under the operating condition as follows: deposition temperature 900 °C, the flux of mixed gases 0.6 l/min, H₂: Ar = 1:0, and the volume ratio of MTS and mixed gases 1:10. Part of calculated results is validated by corresponding experimental data, which implies that this model is valid and reasonable to characterize CVD process of SiC coating.