Influences of growth parameters on the film formation of hexagonal boron nitride thin films grown on sapphire substrates by low-pressure chemical vapor deposition

Hexagonal boron nitride (h-BN) films were grown on c-plane sapphire substrates by low-pressure chemical vapor deposition with BCl3 and NH3 as the boron and nitrogen sources, respectively, and the influences of growth parameters on the film quality were investigated for samples with a thickness of about 1 mu m. The dependence of X-ray diffraction on the growth temperature (T-g) indicated that the crystalline quality is most improved in the sample grown at 1200 degrees C, in which the epitaxial relationship of {100}(h-BN) parallel to {110}(sapphire) and {001}(h-BN) parallel to {001}(sapphire) was confirmed. This condition enhanced lateral growth, resulting in the formation of grains with flat top surfaces. The T-g dependence was discussed in relation to the amorphous AlN formed on the substrate surface and the reaction between BCl3 and NH3 in the vapor phase. The correlation between the structural and luminescent properties, which was found from the T-g dependence of CL, was also discussed. (C) 2016 The Japan Society of Applied Physics