Use of low energy and high frequency PBII during thin film deposition to achieve relief of intrinsic stress and microstructural changes

In this paper, we describe the use of plasma based ion implantation (PBII) together with physical vapour deposition (PVD) to achieve low intrinsic stress and influence the microstructure of coatings. A model is proposed to explain the physical rnechanisms responsible for observed changes in stress. The model is compared with other available models and all are tested against data obtained using a cathodic vacuum arc in background gas to deposit aluminium nitride, titanium nitride and carbon in the presence of high voltage pulsed bias on the substrate. In all three systems, application of PBII resulted in large reductions in intrinsic stress as the voltage and frequency of the pulses was increased. We observed a trade off between applied bias voltage and pulsing frequency. The crystalline systems, aluminium nitride and titanium nitride showed changes in preferred orientation in PBII treated films. An important conclusion of significance to industry is that even relatively low energy (0.5-5 keV) ion implantation can be effectively employed to achieve stress relief. (C) 2004 Elsevier B.V. All rights reserved.