TI-Al-O layers were deposited on Si-[100] wafers at substrate temperatures of 300 degrees C and 600 degrees C, using reactive magnetron sputtering ion plating (R-MSIP). An Al target was sputtered in rf-mode and a Ti target in de-mode simultaneously by an oxygen/argon plasma. The influence of the Al- and Ti-sputter power and of the deposition temperature on composition and morphology of the Ti-Al-O layers were investigated, together with the binding states of the components. All films were characterized by means of X-ray photoelectron spectroscopy (XPS) and X-ray induced Auger electron spectroscopy (AES). Special attention was paid to the interpretation of the O Is and O-KLL fine structure and peak shifts. For the binary phases gamma-Al2O3 and TiO2 (rutile + anatase), good agreement with the literature was observed in each case. For the novel ternary phases, a continuous shift of the kinetic energy of the O-KL23L23 transition and the modified Anger parameter alpha' between the two binary phases could be detected, indicating a wide range of solid solubility between Al2O3 and TiO2. Furthermore, it was possible to determine the bond type of the phases by interpretation of the energy intervals between the peak positions of core- and valence-transitions in the O-KLL group. Results achieved by XPS/XAES were cross checked by comparison with TEM and EPMA results.