Complex characterisation of vacuum arc-deposited chromium nitride thin films

Abstract

Chromium nitride layers were deposited on stainless steel substrates using the vacuum-arc technique. The nitrogen pressure was varied during film preparation. The chemical composition of the layers was determined by XPS and RBS. Special attention was paid to XRD including phase analysis, texture evaluation and stress determination. Different phase compositions were found depending on nitrogen incorporation. Only the film prepared under floating bias potential contained the nearly stoichiometric mononitride. The lattice constants of all detected phases show some deviation from tabulated values. The coatings are strongly textured. All films exhibit compressive residual stress. After subtracting the thermal stress the intrinsic stress was still found to be compressive and of low level. It was practically independent of the nitrogen concentration in the films. Excellent thermal stability of the coatings can be concluded from tempering experiments.