Experimental kinetic study of the chemical vapour deposition of SiC-based ceramics from [formula omitted] gas precursor

Abstract

A detailed kinetic study is presented in order to determine the limiting steps in the chemical vapour deposition of SiC from CH 3SiCl 3 (MTS) H 2 gaseous mixture. On the basis of growth rate measurements, transitions from chemical kinetic control to mass transfer control are found to be induced either by decreasing total flow rate or by increasing temperature and/or total pressure. A pressure-temperature diagram, giving the boundaries between the different domains observed is presented. The chemical kinetics controlled domain includes either 2 or 3 sub-domains, depending on the α = P H 2 P MTS ratio. By taking into account the apparent activation energy, determined in each sub-domain, and the results of the outlet gas phase analysis by mass-spectrometry, three limiting kinetic processes are proposed: CH 3SiCl 3 homogeneous decomposition, heterogeneous formation of SiC and growth inhibition by HCl.