Characterization of cathodic arc deposited titanium aluminium nitride films prepared using plasma immersion ion implantation

This paper investigates thin films of titanium aluminium nitride grown using a stoichiometric metallic cathode in a cathodic arc vapour deposition system with plasma immersion ion implantation. The effect of various deposition conditions on the stress, microstructure and composition are evaluated. In general, the films were found to be both titanium and nitrogen rich. The application of voltages of 2 kV and greater was found to dramatically reduce the stress in the films. This stress reduction was found to be less pronounced at lower nitrogen flow rates due to a reduction in nitrogen implantation. The microstructure of the films was found to be cubic and at high voltages exhibited preferred orientation with {200} planes parallel to the surface of the film. We employ density functional theory to calculate the {100} and {111} surface energies and elastic constants for cubic titanium aluminium nitride. Using these calculated values, we explain this preferred orientation using a model which minimizes both surface energy and bulk strain energy.