The growth of epitaxial (001) CeO2 on a (001) Ge surface using a reactive sputter deposition method is reported. Hydrogen gas (4%H-2/Ar sputtering gas) is introduced during film growth in order to reduce or eliminate the presence of the GeO2 from the semiconductor surface during the initial nucleation of the metal oxide film. A metal cerium target was used as the cation source, with water vapor serving as the oxidizing species. Epitaxial films were sputter deposited at a substrate temperature of 550 degreesC in a H2O vapor pressure of approximately 10(-3) Torr. The hydrogen partial pressure and substrate temperature were selected to be sufficiently high such that the germanium native oxides are thenriodynamically unstable. The Gibbs free energy of CeO2 is larger in magnitude than that of the Ge native oxides, making it more favorable for the metal oxide to reside at the interface in comparison to the native Ge oxides. (C) 2004 Elsevier B.V. All rights reserved.