Optical characterization of TiN produced by metal-plasma immersion ion implantation

The dependence of the optical properties of TiN thin films prepared by metal-plasma immersion ion implantation (Me-PIII), using a cathodic arc as the source of Ti ions, on the pulse voltage and the gas composition was investigated. High voltage pulses up to −10 kV at a duty cycle of 9% were used while the gas flow was varied between 20 and 50 sccm. For all bias voltages TiN films oriented with the (100) axis normal to the surface was obtained. For the screened plasma energy ωps a strong dependence on the gas mixture was found, increasing from 2.6 eV for high flow/current (FN2/Iarc) ratios to more than 3.5 eV for low FN2/Iarc ratios. This is correlated with a reduction of the nitrogen content as the composition changes concurrently from TiN0.95 to TiN0.55.