Chemical vapor deposition of hexagonal boron nitride films in the reduced pressure

Hexagonal boron nitride (h-BN) films were deposited onto a graphite substra te in reduced pressure by reacting ammonia and boron tribromide at 800-1200 degrees C. The growth rate of h-BN films was dependent on the substrate te mperature and the total pressures. The growth rate increased with increasin g the substrate temperature at the pressure of 2 kPa, while it showed a max imum value at the pressures of 4 and 8 kPa. The temperature at which the ma ximum growth rate occurs decreased with increasing total pressure. With inc reasing the substrate temperature and total pressure, the apparent grain si ze increased and the surface morphology showed a rough, cauliflower-like st ructure. (C) 2000 Elsevier Science Ltd.