Effect of Ti interlayer and bias on structure and properties of TiN films

The paper reports on properties and structure of the TiN films, which have been deposited on titanium interlayer covering a steel substrate. The Ti interlayer and the TiN film were prepared by d.c. magnetron sputtering in Ar and Ar + N2 mixture, respectively. Three Ti interlayers with different thickness hTi = 0.01, 0.1 and 0.2 μm were prepared under the same conditions and investigated. It was found that the macroscopic residual stress in the TiN films is compressive and increases with the increasing negative bias up to approximately −150V. Also the size of the TiN crystallites decreases with the increasing negative substrate bias, varying between 250 nm and 11 nm. The critical load, which characterises the film adhesion, increases with increasing hTi For hTi ≥ 0.1 μm, the critical load almost does not depend on the bias voltage.