Improvement of the crystallinity of 3C-SiC films by lowering the electron temperatures in the afterglow plasma region using triode plasma CVD

Crystalline SiC films were grown at low temperatures by triode plasma chemical vapor deposition (CVD) using dimethylchlorosilane diluted with hydrogen as the source gas. Influences of the grid bias on the electron temperature in the discharge region and in the afterglow region, and on the properties of the SiC films such as crystallinity, chemical bonding structure, and composition were investigated. Under negative grid bias conditions, the electron temperature in the discharge region increased and that in the afterglow region became about one-tenth of that under positive bias conditions. The crystallinity of the SiC films grown under low electron temperatures in the afterglow plasma region was remarkably improved and the composition of the films became stoichiometric. Under the negative grid bias, a high density of active hydrogen radicals was generated in the discharge region, diffused toward the substrate surface, and extracted the weak bonds or excessive methyl groups from the growing film surface under low electron temperature. As a result of these processes, SiC films with good crystallinity were grown.