A study of CrNx thin films by X-ray photoelectron spectroscopy

X-ray photoelectron spectroscopy has been employed to study the electronic structure of CrNx thin films. The films have been deposited with varying concentration of nitrogen on a stainless steel substrate by a d. c. magnetron sputtering technique. The Cr 2p, Cr LMM Auger, N 1s, and N KLL Auger regions were investigated using Mg K-alpha radiation. Results indicate changes in the electronic structure of Cr and N in these films. The Auger parameter shows an increasing trend for Cr and a decreasing trend for N. This has been interpreted as increasing charge transfer from Cr to N with increasing content of nitrogen. The full width at half maximum observed for Cr 2p(3/2) peak shows an increasing trend with the nitrogen concentration. The density of states at the Fermi level estimated from the asymmetry index of the Cr 2p(3/2) peak is larger than that for elemental chromium. However, in the films a decreasing trend is observed for the density of states with increasing nitrogen content. The chemical shift for the Cr 2p(3/2) peak shows a decreasing trend while that for the N 1s peak shows an increasing trend. Using the Auger parameter as an approximation for the relaxation shift, the trend in the contribution due to configuration changes in these films has been estimated. The configuration change (hybridization effects) is observed to increase with the increase in the nitrogen content. These changes are interpreted as increasing hybridization of the Cr 3d and 4sp orbitals, with N 2p orbitals as the concentration of nitrogen increases. The observations are corroborated by results on the stoichiometric compound CrN by other studies. (C) 1999 Elsevier Science B.V. All rights reserved.