Composition, microstructure, and thermal stability of silicon carbide chemical vapor deposited at low temperatures

In this paper, the authors have examined the chemical composition, microstructure, and thermal stability of silicon carbide chemical vapor deposited at relatively low temperatures ranging from 1000 to 1300°C. Within the present deposition-temperature range, pure silicon carbide was obtained that was composed mainly of cubic-type beta silicon carbide with a small amount of hexagonal-type silicon carbide. Neither free silicon nor free carbon was found. An Auger spectrum from the surface of the deposit revealed that there was a small amount of chlorine, sulfur, and oxygen on the surface of the silicon carbide. X-ray diffraction and transmission electronic microscopy results indicated that the silicon carbide was poorly crystallized and that the crystallite size was very fine (∼10 nm). As the deposition temperatures decreased, the crystallite size became smaller. After silicon carbide had been annealed at 1550°C for 5 h in vacuum, crystallite growth and weight loss were noted.