Study on the resistivity and infrared emissivity of TiNx films at different sputtering power

Abstract

TiNx films with low infrared emissivity were prepared using DC reactive magnetron sputtering technique. The influence of sputtering power (50, 80, 100, and 200 W) on the morphology, structure, adhesion force, resistivity and infrared emissivity was investigated systematically. The thickness of the prepared TiNx films was in the range of 381–987 nm. The films grew with preferred orientation of (200) plane at lower sputtering power, while the preferred orientation was (220) plane at higher sputtering power. The N/Ti stoichiometry ratio increased from 0.67 to 0.96 with the increase of sputtering power, and the deposited TiNx thin films were off stoichiometry. Due to more formation of bonds of Ti–N in TiNx crystal, the adhesion force increased with increasing of sputtering power. The resistivity and infrared emissivity of TiNx films first deceased, and then increased with the increase of sputtering power. Defects in TiNx films prepared at 50 W led to high resistivity and infrared emissivity. The lattice distortion caused by Ti atoms was considered to play an important role in the increase of the resistivity of TiNx films at 200 W. The decrease of carrier density caused by decreased nitrogen vacancies should be the reason for the increase of the infrared emissivity of TiNx films at 80–200 W.