Chemical vapor deposition of silicon carbide at various temperatures and surface area/volume ratios

Chemical vapor deposition of Sic from methyltrichlorosilane and hydrogen was studied as a function of temperature using substrates with different surface area / volume ratios. Deposition rates and composition of the deposits at various temperatures and surface area / volume ratios were determined as a function of reactor or substrate length, respectively. The gas phase composition was analyzed as a function of residence time. Si is deposited in high excess at low temperatures and especially low surface area / volume ratios. The unusual temperature dependence of the overall deposition rate with rate maxima at about 900 and 1025 °C is caused by temperature selective depositions of both, SiC and Si. Deposition of stoichiometric SiC and a continuous increase of the deposition rate are obtained at a high surface area / volume ratio. The results are discussed on the basis of a novel chemical model