Morphology control of conductive TiN films produced by air-based magnetron sputtering

TiN is an important coating material with many technological applications because of its high hardness and corrosion resistance, as well as low resistivity. Many more applications are expected if the morphology of TiN thin films can be facilely tailored during sputtering. The objective of this work is to produce conductive TiN films with various morphologies by air-based sputtering. The sputtering was conducted at a low-vacuum base pressure through varying the air/Ar flow ratios. The simulated-air consisting of pure N2 and O2 with a fixed ratio of 79/21 was also employed as a reactive gas for comparison. Obtained results concerning the obtained crystalline phases, microstructures, morphologies, and electrical resistivities are very similar, indicating that trace components in air have little effects on the characteristics of the films. Granular TiN films were formed at relatively low air/Ar flow ratios while pyramidal TiN films were produced at higher air/Ar flow ratios. This is associated with that the texture of the films turned from rather random orientations to mainly a (111) preferred orientation. The morphology evolution and texture development with deposition time have also been studied. The resistivities of the air-produced TiN films were in the range of 90-160 μΩ-cm, which lies within the range of those reported in the literature. The conductive TiN films with different surface morphologies produced by such a facile air-based sputtering technique may bring in more technological applications.