Optical properties of the HfO2-x N x and TiO2-x N x films prepared by ion beam sputtering

Optical characteristics of the HfO2 - x N (x) and TiO2 - x N (x) films obtained by reactive ion beam sputtering have been investigated by spectral ellipsometry. The chemical composition of the films was determined using X-ray photoelectron spectroscopy. The nitrogen content in the oxynitride films (determined by the N-2/O-2 ratio in the gas mixture during synthesis) reached a parts per thousand 9 at % for TiO2 - x N (x) and a parts per thousand 6 at % for HfO2 - x N (x) . It is found that the dispersion relations n(lambda) and k(lambda) for the TiO2 - x N (x) films change from those characteristic of titanium dioxide to those typical of titanium nitride with an increase in the nitrogen content from 0 to a parts per thousand 9 at %. The optical parameters of the HfO2 - x N (x) films depend weakly on the nitrogen content in the range 0-6 at %.