Initial stages of growth during boron carbide chemical vapor deposition

The initial stages of growth of boron carbides from a BCl₃/H₂/hydrocarbon vapor on molybdenum were investigated. The initial growth of boron carbide was strongly dependent on the type and concentration of hydrocarbon in the vapor. From the results of the experiments it was concluded that an ‘‘overlayer’’ of adsorbed hydrocarbons was formed on the surface. The overlayer inhibited some reactions on the surface and affected the growth rate, the morphologies of the nuclei, as well as the growth rates of molybdenum borides.