Solid-state reactions of silicon carbide and chemical vapor deposited niobium

Niobium films were deposited on silicon carbide by chemical vapor deposition using niobium chloride and hydrogen at a temperature range of 900-1300°C. The solid-state reactions between the deposited niobium and silicon carbide matrix were studied by examining the obtained films using X-ray diffraction and energy dispersion spectroscopy. The results indicated that niobium silicides could be formed at the beginning, which blocked further reactions between carbon and niobium to form niobium carbides. When the deposition temperature was increased, silicon would diffuse outward, which allowed the formation of niobium carbides. The reaction process and mechanism are discussed based on the thermodynamics and kinetics.