Growth Mechanism of Silicon Carbide Films by Chemical Vapor Deposition below 1273

SiC films were prepared from the reaction of Si₂H₆ with C₂H₄ or C₂H₂ at relatively low temperatures ranging from 873 K to 1273 K by low-pressure chemical vapor deposition. The deposition rate profiles determined by gravimetry and the alloy composition (carbon content, x, for Si_1-xC_x) profiles determined by X-ray photoemission spectroscopy in the reactor were mainly investigated. The results revealed that the carbon content, x , was a function of the temperature, ratio of partial pressures of source gases, and source gas species (C₂H₄, C₂H₂). From these results we deduced that SiC formation occurred by two major competing reaction processes: (1) the silicon deposition processes, SiH₂ Si (wall) and Si₂H₆ Si (wall), and (2) the carbon deposition process, C₂H₄+ SiH₂ vinylsilane or C₂H₂+ SiH₂ ethynylsilane.