Effect of CH4/SiCl4 ratio on the composition and microstructure of 〈110〉-oriented β-SiC bulks by halide CVD

Halide chemical vapor deposition process was carried out for fast fabricating oriented stoichiometric β-SiC through controlling flow rate of precursors (SiCl4 and CH4). The effects of molar ratio of C and Si precursors (RC/Si) on composition, preferred orientation, microstructure and deposition rate (Rdep) were investigated. The deposits transformed from silicon-rich to stoichiometric β-SiC to carbon-rich with increasing RC/Si. 〈110〉-oriented stoichiometric β-SiC with lower density of defects were obtained at RC/Si in the range of 0.86-1.00, where the maximum Rdep was 883 μm/h at RC/Si = 1.00, leading to a thickness of 1.7 mm in 2 h deposition. Formation of ridge-like morphology has been discussed based on a twin plane propagation model.