Preparation and oxidation of composite TiN-AlN films from alkoxide solutions by plasma-enhanced CVD

Composite and compositionally graded (CGed) TiN-AlN films were deposited on Si wafers at 600 °C from Ti- and Al-alkoxide solutions by N2 plasma-enhanced chemical vapor deposition (CVD). The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Vickers micro-hardness. In the composite TiN-AlN films, the Ti and Al contents varied linearly and complementarily with solution composition, the N content ranging from 35 to 40 at.%. In the CGed films, the Al component decreased complementarily with increasing Ti toward the substrate. Cross-sectional SEM observation showed both films to be about 1 μm thick with a columnar structure. Oxidation of the composite and CGed films was performed at 500, 700, and 900 °C in air for 1 h. The improvement of oxidation resistance in both composite and CGed films is discussed on the basis of the XRD and SEM observations, and the XPS analysis of the oxidized films.