Thin TiN and TiB 2 coatings with low residual stress deposited at different temperatures by cathodic arc ion plating

Abstract

It was shown previously that the Hyper-Ion process, a short pulsed very high voltage bias, reduces the residual stress in coatings during deposition. In this study, it is shown that the residual stress in thin (less than 0.11 μm) TiB 2 films increases with deposition temperature and, remarkably, falls with thickness in this range then increases again. It can be reduced down to a minimum value of about 1 GPa independent of thickness in this range by applying the Hyper-Ion process during deposition or by post ion implantation. In TiN films, a similar thickness dependence of the residual stress is found; at 25°C the Hyper-Ion process reduces the stress to a minimum value of about 0.7 GPa which is not reduced further by post ion implantation. At 450°C under high bias, the Hyper-Ion process is not effective but the residual stress can be reduced by post implantation. It is concluded that the Hyper-Ion process can be very effective in reducing the residual stress and needs to be tailored to the specific deposition process.