The role of the nitrogen flow rate on the transport properties of CrN thin films produced by DC magnetron sputtering

Abstract

Thin films of CrN were synthesized in a DC magnetron sputtering system using a mixture of Ar+N2. The chemical composition and bonding configuration were examined using X-ray photoelectron spectroscopy (XPS) revealing CrN bonds. The stoichiometry variation dependence on the N2 flow was also analyzed using Auger spectroscopy. Both, The XPS and Auger analyses were performed in situ. A gradual increase was observed in the nitrogen concentration in the coatings as the N2 was increased into the reaction chamber. The electrical behavior was studied while varying the N2 concentration. A lower resistivity was observed as the nitrogen concentration was increased into the sample before reaching the stoichiometric concentration; however, the resistivity increased at higher nitrogen concentrations (overstoichiometric coatings). Considering that chromium is a magnetic material, a slope change in the resistivity was observed around the Néel temperature. Furthermore, the obtained Hall coefficient showed changes in the carrier type (negative or positive) depending on the nitrogen concentration of the CrN coatings.