Influence of substrate bias voltage on structure and properties of Cr-Mo-Si-N coatings prepared by a hybrid coating system

Abstract

Cr-Mo-Si-N coatings were prepared on Si wafer by a hybrid coating system combining arc ion plating and magnetron sputtering at the substrate bias voltage ranging from 0 to -400 V. The results showed that the deposition rate, film microstructure, and properties of the coatings was significantly altered with increase of bias voltage. The deposition rate changing from 2.2 to 1.6 mu m/h was observed due to the resputtering effect. Only CrN phase can be detected in the XRD spectra of all the Cr-Mo-Si-N coatings. Grain size diminishment and orientation transformation from (200) preferred to random was observed with increase of bias voltage. The maximum microhardness of about 49 GPa was obtained at the bias voltage of -50 V. The internal stress in Cr-Mo-Si-N coatings was compressive and ranging from -1.2 to -2.7 GPa. The microhardness enhancement was discussed considering grain size diminishment and residual stress in the coatings. The surface topography of the Cr-Mo-Si-N coatings was also investigated in this study. (c) 2008 Elsevier B.V. All rights reserved.