Substrate-temperature dependent structure and composition variations in RF magnetron sputtered titanium nitride thin films

Using RF reactive magnetron sputtering process in a 100% nitrogen atmosphere, TiNx thin films were deposited on a quartz substrate. The crystal structure and optical properties of the as-deposited thin films, as a function of substrate temperature, were studied. From room temperature till 600 °C, with increasing temperature, the crystal structure changed from tetragonal to cubic, with ‘x’ in TiNx increasing with the substrate temperature. In the entire temperature range x was less than 1. Simultaneously, the optical plasma band of the film shifted from the ultra-violet region having energy of 4.83 eV to the visible region corresponding to energy of 2.47 eV. The width of the transmittance band in the visible range varied with temperature between 460 nm and 620 nm. All the films exhibited a PL (photoluminescent) single band in the middle of the visible region.