Epitaxial growth of praseodymium oxide (Pr2O3) and praseodymium silicate on Si(001) using high-temperature effusion sources is investigated. Pr2O3 and Si are co-evaporated in order to alloy Pr2O3 with Si. The grown layers are studied by in situ reflection high-energy electron diffraction (RHEED) and in-plane grazing incidence X-ray diffraction (XRD). A reduction of an undesired interfacial layer at the Pr2O3/Si interface is achieved by adding Si during the growth. In addition, the existence of a small amount of the hexagonal phase of Pr2O3 in the layer is observed. The leakage current depends on the Si flux and the minimum leakage current is obtained for the layer that shows the highest contrast RHEED pattern with hexagonal phase fraction. (c) 2006 Elsevier B.V. All rights reserved.