Ion assisted laser processing of cubic boron nitride films

We have synthesized cubic boron nitride films using ion assisted laser deposition, where boron is evaporated by laser ablation and the substrate is bombarded concurrently with nitrogen ions. The films were characterized by Auger electron spectroscopy (AES), Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM) techniques. The electron diffraction patterns from these specimens provide unambiguous evidence for hexagonal (h-BN) and cubic (c-BN) boron nitride phases. The films deposited on silicon were found to be either polycrystalline h-BN or c-BN depending upon the deposition conditions. The films deposited on diamond were epitaxial cubic boron nitride with no interposing layer. We have performed a detailed study of microstructures of c-BN varying from fine-grain polycrystalline to epitaxial structures.