Deposition on Si-face 4H-SiC(0001) substrates resulted in polycrystalline rhombohedral boron carbide as seen from the 2θ/ω diffractogram (Figure ) and FT-IR reflectance spectra (Figure ) of a film deposited at 1400 °C. Pyrolytic graphite could also be detected under some conditions (Figure ). The orientation of the r-BxC crystals and formation of graphite were found to be strongly dependent on the growth temperature and on the residence time of the gas in the susceptor, as presented in Figure .