Relation between stress in cubic boron nitride films and the in plane TO phonon energy

The high intrinsic stresses in as-deposited cBN films are relaxed employing thermal treatment and ion implantation. In-situ stress measurement and ex-situ polarized infrared reflection spectroscopy are utilized to study correlations between stress and cBN TO phonon energy. The in plane TO phonon energy of cBN films is found to be not unambiguously dependent upon the film stress in contrast to the dependence of the phonon energy of cBN crystallites upon hydrostatic pressure. Factors affecting the relation between stress and phonon position are discussed.