Kinetic and gas-phase study of the chemical vapor deposition of silicon carbide from C2H3SiCl3/H2

The chemical vapor deposition (CVD) of silicon carbide from vinyltrichlorosilane (VTS) was studied to identify a range of conditions leading to pure crystalline SiC. The deposition rate was recorded to evidence the various deposition regimes. Gas phase, elemental analyses and infiltration tests were also performed. Three distinct chemical reaction regimes were identified. In CVD conditions, carbon is co-deposited at low temperature while VTS is only partially decomposed. In infiltration conditions, the composition switches to pure SiC inside the porous substrate because of a depletion of reactive hydrocarbon species. Competing heterogeneous reactions are responsible for a hysteresis versus temperature, in both deposition rate and composition of the deposit. The high temperature domain is the most suitable to deposit pure crystalline SiC in CVD conditions. Hydrogen dilution strongly accelerates the homogeneous decomposition of VTS as compared to argon. Assumptions on the reaction mechanism were proposed describing the chemistry of this precursor.