Deposition of NbN thin films by DC magnetron sputtering process

Thin films of niobium nitride (NbN) were deposited on SKD11 tool steel substrate by a DC magnetron sputtering system. The influence of the N-2/Ar gas ratio of the inlet gases, the deposition temperature, the substrate bias potential on the mechanical and the structural properties of the films were investigated. X-ray diffraction data showed that cubic NbN was formed at a low N,l Ar gas ratio. With the increase in the N-2/Ar gas ratio, hexagonal NbN was formed, resulting in a mixture of cubic NbN and hexagonal NbN. The hardness of the films also increased with an increase in the deposition temperature up to 300degreesC. Adhesion of the films decreased, however, with an increase in the deposition temperature., The hardness of the films reached maximum level at the bias potential of -200 V and decreased with a further increase of the bias potential. The films deposited at the substrate bias potential range from -50 to -150 V exhibited relatively high adhesion. (C) 2003 Elsevier B.V. All rights reserved.