An XPS study on oxidation of exposed-to-air Cr 1− x Zr x N film surfaces

Chromium zirconium nitride (CrZrN) thin films were prepared on Si (100) substrates with various Zr contents by using co-sputtering technique. The Zr content was varied by variation of the Zr sputtering current from 0.2 to 0.8 A while the Cr current and the N2 flow rate were kept at 0.8 A and 6.0 sccm, respectively, to fix the concentration of Cr and N atoms. An oxidation caused by exposure to air of the Cr1−xZrxN thin films were studied by using X-ray photoelectron spectroscopy (XPS). Chemical composition analysis of XPS spectra revealed that oxygen detected on the film surfaces was increased with the rise in the Zr content. Deconvolutions of O 1s photoemission lines revealed bonding separately of O atoms to Cr and Zr atoms. Moreover, the fraction of the O–Cr bond was increased with the increasing Zr content.