Polarized Raman spectroscopy of chemically vapor deposited diamond films

Polarized micro-Raman spectra of chemically vapor deposited diamond films are presented. It is shown that important parameters often extracted from the Raman spectra such as the ratio of the diamond to nondiamond component of the films and the estimation of the level of residual stress depend on the orientation of the diamond crystallites with respect to the polarization of the incident laser beam. The dependence originates from the fact that the Raman scattering from the nondiamond components in the films is almost completely depolarized while the scattering from the diamond components is strongly polarized. The results demonstrate the importance of taking polarization into account when attempting to use Raman spectroscopy in even a semiquantitative fashion for the assessment of the purity, perfection, and stress in chemical vapor deposition diamond films.