Influence of substrate bias on the structure and properties of ZrN films deposited by cathodic vacuum arc

Abstract

ZrN films were deposited by cathodic vacuum arc (CVA) technique in N 2 atmosphere at low temperature with different substrate bias. The ZrN films deposited are atomically smooth. The influence of substrate bias at the wide range (0 to −500 V) on the deposition rate, surface morphology, crystal structure, internal stress, and mechanical properties of the ZrN films were systematically investigated. Increasing substrate bias results in the decrease of deposition rate and the increase of surface roughness. It was found that there is a strong correlation between the substrate bias, film structure and properties. At the bias of 0 V, ZrN films characterize with random orientation, low surface roughness, small grain size. With the increase of bias, the structure changes from random orientation to (1 1 1) preferred orientation and then to (2 2 0) orientation. As substrate bias increases to about −150 V, the internal stress, hardness and Young's modulus increase to maximum. A further increase of bias results in the gradual decrease to lower level.