Preparation of ultra-thick β-SiC films using different carbon sources

Polycrystalline ultra-thick β-SiC films have been grown on graphite substrates via halide chemical vapour deposition method by using tetrachlorosilane (SiCl₄) as silicon source, whereas methane (CH₄), acetylene (C₂H₂), propane (C₃H₈) and liquid petroleum gas as carbon sources, respectively. The effects of deposition temperature (T_dep) and carbon source on the orientations, microstructures and deposition rate (R_dep) were investigated. R_dep of β-SiC films dramatically increased with increasing T_dep. In the case of C₂H₂, it provides a sufficient source of carbon and results in the maximum R_dep under identical T_dep compared to the other carbon sources. Conversely, CH₄ decomposition in the Si-C-Cl-H system was proved to be inactive with SiCl₄ in the entire range of T_dep. The orientations of the β-SiC films transform from 〈111〉 to random to 〈110〉 with increasing T_dep, and highly 〈111〉- and 〈110〉-oriented β-SiC films were fabricated at 1473 and 1773 K, respectively.