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 (Tdep) and carbon source on the orientations, microstructures and deposition rate (Rdep) were investigated. Rdep of β-SiC films dramatically increased with increasing Tdep. In the case of C2H2, it provides a sufficient source of carbon and results in the maximum Rdep under identical Tdep 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 Tdep. The orientations of the β-SiC films transform from 〈111〉 to random to 〈110〉 with increasing Tdep, and highly 〈111〉- and 〈110〉-oriented β-SiC films were fabricated at 1473 and 1773 K, respectively.