Preparation of titanium oxynitride thin films by reactive sputtering using air/Ar mixtures

In the literature titanium oxynitride (TiNxOy) films have often been prepared by controlling N2/O2/Ar mixing gases in physical vapor deposition. In this study, TiNxOy films were prepared by d.c. magnetron sputtering using air/Ar mixtures. Replacing N2/O2 with air as a reactive gas allowed the process performed at high base pressures, i.e., low vacuum, which could drastically reduce processing time while achieving similar quality of the films prepared at a low base pressure. When the air/Ar flow ratio increased from 0.15 to 0.30, the color of the films changed from light golden to dark golden and X-ray diffraction patterns show that the preferred orientation of films with rock-salt structure changed from (111) into (200). The oxygen content in the TiNxOy films increased with increasing the air/Ar ratio, as determined by X-ray photoelectron spectroscopy. The thickness of the films decreased with increasing the air/Ar ratio, revealing the target poisoning effect especially at high air/Ar ratios. Electrical resistivities of the films increased with the ratio owing to the increase of oxygen content in the films.