We investigated on the structural properties of Al2O3 dielectrics grown on TiN metal substrates using an atomic layer deposition technique with tri-methyl-aluminum and either O-3 or H2O as the precursor and oxidant, respectively. The structural and morphological features of these films were examined by atomic force microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy measurements. We find that Al2O3 dielectric films with the O-3 oxidant exhibit a rough morphology, a thick TiO2 film, and a small amount of contaminants such as carbon and hydrogen. The reason for the rapid diffusion of oxygen atoms into the TiN lattice leads to the formation of TiO2 layer on the TiN substrate. This is due to the higher oxidation potential of the O-3 compared to the H2O. (c) 2008 Elsevier B. V. All rights reserved.