PREPARATION AND CHARACTERIZATION OF NANOCRYSTALLINE CUBIC BORON-NITRIDE BY MICROWAVE PLASMA-ENHANCED CHEMICAL VAPOR-DEPOSITION

Polycrystalline boron nitride films have been deposited using microwave plasma-enhanced chemical vapor deposition. IR absorption spectra of films deposited using NaBH4 as the boron source in NH3 and H-2 gases showed absorptions which are nearly the same as the characteristic vibrational modes seen in cubic and pyrolytic boron nitrides. Films deposited at 5 Torr also showed electron diffraction patterns for pyrolytic boron nitride, turbostratic boron nitride and cubic boron nitride. At higher gas pressures, only rings consistent with the formation of amorphous and cubic boron nitride were observed. Although the Raman spectra from a film deposited at 60 Torr showed broad peaks at approximately 1080 and approximately 1310 cm-1, the positions of the Raman lines for cubic boron nitride, no x-ray diffraction lines could be observed except that of the silicon substrate.