Boron-carbon-silicon film chemical vapor deposition by boron trichloride, dichlorosilane and monomethylsilane gases

Abstract

A boron-carbon-silicon film was formed by an atmospheric pressure chemical vapor deposition method using a gas mixture of boron trichloride, dichlorosilane and monomethylsilane in ambient hydrogen at 800–1000 °C. The boron, carbon and silicon concentrations in the obtained film were about 15–30 %, 0–10 % and 50–80 %, respectively. With the increasing monomethylsilane gas flow rate, the carbon and silicon concentrations in the obtained film increased and decreased, respectively. In the obtained film, various chemical bonds between the boron, carbon and silicon existed, except for the carboncarbon bond. The following conclusions were obtained. (i) The carbon atoms existing at the surface have a chemical bond with the boron atoms, but not with the carbon and silicon atoms. (ii) The surface intermediate compound of boron chloride helps incorporating the carbon, while that of dichlorosilane does not. (iii) The etching by the hydrogen chloride gas significantly influenced the film formation process at higher than 900 °C.