COMPARISON OF SURFACE OXIDATION OF TITANIUM NITRIDE AND CHROMIUM NITRIDE FILMS STUDIED BY X-RAY-ABSORPTION AND PHOTOELECTRON-SPECTROSCOPY

Surface oxidation mechanisms of TiN and CrN films were studied by mean s of x-ray photoelectron (XPS) and absorption spectroscopy (XAS). In t he N 1s XPS spectra of both the oxidized TiN and CrN films, a feature assigned to molecular nitrogen was observed in addition to a feature a ssigned to nitride. The assignment was confirmed by the N K-edge XAS s pectra of the TiN and CrN films which exhibited a sharp feature at 401 .4 eV. Besides these features, the N 1s XPS spectra of the oxidized Ti N films showed a third feature, which was assigned to N-X-Ti-O-Y like structures taking into account the change in the Ti 2p XPS spectra. Ho wever, no evident feature assigned to N-X-Ti-O-Y like structures was o bserved in the XAS spectra because of the overlapping with the nitride features. The above results indicated that the CrN films directly cha nged to Cr2O3 with the formation of molecular nitrogen in the intersti tial positions of the surface oxide layers, while the TiN films were o xidized to TiO2 through the formation of N-X-Ti-O-Y like structures. T he formation of the N-X-Ti-O-Y like structures may allow the rapid dif fusion of oxygen and hence lower the oxidation resistance of TiN films . (C) 1997 American Vacuum Society.