Phase identification of boron nitride thin films by polarized infrared reflection spectroscopy

Six different types of boron nitride films were investigated by polarized infrared reflection spectroscopy. Films with a highly cubic, mixed cubic and non-cubic, and exclusively non-cubic phase composition were synthesized using ion beam assisted deposition. Additionally, post-deposition argon ion irradiated cubic and non-cubic boron nitride films as well as nitrogen implanted boron sample were analyzed. Using this technique, besides the cubic phase, two different non-cubic modifications, layered anisotropic and amorphous, could be distinguished. A preferentional orientation of the normal axis of the sp2-bonded basal planes parallel to the substrate surface was observed.