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

In this paper, the authors have examined the chemical composition, microstr ucture, and thermal stability of silicon carbide chemical vapor deposited a t relatively low temperatures ranging from 1000 to 1300 degrees C. Within t he present deposition-temperature range, pure silicon carbide was obtained that was composed mainly of cubic-type beta silicon carbide with a small am ount of hexagonal-type silicon carbide. Neither free silicon nor free carbo n was found. An Auger spectrum from the surface of the deposit revealed tha t there was a small amount of chlorine, sulfur, and oxygen on the surface o f the silicon carbide. X-ray diffraction and transmission electronic micros copy results indicated that the silicon carbide was poorly crystallized and that the crystallite size was very fine (similar to 10 nm). As the deposit ion temperatures decreased, the crystallite size became smaller. After sili con carbide had been annealed at 1550 degrees C for 5 h in vacuum, crystall ite growth and weight loss were noted. (C) 2000 Elsevier Science S.A. All r ights reserved.