Dependence of optical properties and hardness on carbon content in silicon carbonitride films deposited by plasma ion immersion processing technique

Abstract Materials with Si–C–N composition are of great interest due to their remarkable properties such as high hardness and oxidation resistance. In this study amorphous silicon nitride and silicon carbonitride films were deposited on glass, fused silica, and carbon substrates by the plasma immersion ion processing technique. Gas pressure during the deposition was kept around 0.13 Pa (1 mTorr) and SiH 4 , N 2 , Ar and C 2 H 2 gas mixtures were used. Film hardness, composition and UV–visible optical absorption were characterized using nanoindentation, ion beam analysis techniques, and UV–visible spectroscopy, respectively. The films exhibit high transparency in the visible and near UV regions. Addition of the carbon to the films causes decrease in the density of the films, as well as decrease in hardness and transparency. These results suggest that in the low energy regime of PIIP the deposition of hard carbon composites with nitrogen and silicon does not take place.