Influence of substrate bias on the structure and mechanical properties of ta-C : W films deposited by filtered cathodic vacuum arc

Tungsten containing tetrahedral amorphous carbon (ta-C:W) films were deposi ted by an off-plane double bend filtered cathodic vacuum arc technique from a composite target. Raman spectroscopy and atomic force microscopy (AFM) w ere used to characterize the film structure and surface morphology. Substra te bending method and nanoindenter were used to determine the internal stre ss, hardness, and Young's modulus. The influence of substrate bias on the s urface morphology, structure, and mechanical properties was systematically studied. All the deposited films were very smooth. The internal stress, har dness and Young's modulus for the deposited films increase with increasing substrate bias, reaching the maximum at a substrate bias of - 80 V, then de crease drastically with increasing substrate bias to - 200 V. Further incre ase of substrate bias results in the slight decrease of internal stress, ha rdness and Young's modulus. The correlation between the structure and the m echanical properties of the deposited films was established. (C) 2001 Elsev ier Science B.V. All rights reserved.