THIN TIN AND TIB2 COATINGS WITH LOW RESIDUAL-STRESS DEPOSITED AT DIFFERENT TEMPERATURES BY CATHODIC ARE ION PLATING

It was shown previously that the Hyper-Ion process, a short pulsed ver y high voltage bias, reduces the residual stress in coatings during de position. In this study, it is shown that the residual stress in thin (less than 0.11 mu m) TiB2 films increases with deposition temperature and, remarkably, falls with thickness in this range then increases ag ain. It can be reduced down to a minimum value of about 1 GPa independ ent of thickness in this range by applying the Hyper-Ion process durin g deposition or by post ion implantation. In TiN films, a similar thic kness dependence of the residual stress is found; at 25 degrees C the Hyper-Ion process reduces the stress to a minimum value of about 0.7 G Pa which is not reduced further by post ion implantation, At 450 degre es C under high bias, the Hyper-Ion process is not effective but the r esidual stress can be reduced by post implantation. It is concluded th at the Hyper-Ion process can be very effective in reducing the residua l stress and needs to be tailored to the specific deposition process.