A stoichiometric HfO2 film was successfully prepared using direct reactive sputtering deposition on a native SiO2/Si wafer, before which an ultrathin Hf metal film was deposited as a buffer layer. X-ray photoelectron spectroscopy depth profiling technique was employed to investigate the interface chemistry of the obtained structure. It was observed that Hf silicates were formed in the interfacial layer. The binding energies of Hf 4f and O 1s shifted to higher binding energy side synchronously during the removal of the contaminant layer. These shifts were attributed to the modification of the surface potential by Ar+ sputtering. (C) 2004 Elsevier B.V. All rights reserved.