Surface reflectivity of TiN thin films measured by spectral ellipsometry

Abstract

Optical properties of TiN thin films have been measured by spectroscopic ellipsometry in the UV-visible range. TiN is a transition metal nitride showing some singular properties such as hardness, wear resistance and golden color, which are very useful in metallurgical and optical coatings. TiN thin films were prepared by plasma enhanced chemical vapor deposition from a gas mixture of N2, H2 and TiCl4 vapor. The properties of TiN thin films mainly depend on deposition conditions and film stoichiometry. In particular, optical properties of TiN thin films can be strongly modulated by technological parameters such as substrate temperature. dilution of gases and RF-power. The reflectivity spectra of TiN films were calculated from ellipsometric measurements and were compared to the evaporated and crystalline gold reflectivity spectra. The reflectivity spectra of TiN films show a shape similar to that of gold, with an edge in the visible region, although the TiN films present lower reflectivity than the gold film.