The heteroepitaxial growth of Er2O3 films has been achieved on Si(0 0 1) substrates by molecular beam epitaxy using metallic Er source at a substrate temperature of 700 degrees C in an oxygen ambient pressure of 7 x 10(-6) Torr. The epitaxial relationship between the single crystalline Er2O3 films and the Si substrate, as determined by X-ray diffraction (XRD) and reflection high-energy electron diffraction, is Er2O3(1 1 0)//Si(0 0 1), Er2O3[0 0 1]//Si[1 1 0] or Er2O3[1 1 0]//Si[1 1 0]. At lower temperatures and/or lower oxygen ambient pressures, ErSi2, silicide is formed besides Er2O3 and results in pinholes in the films as observed by XRD and atomic force microscopy. Both oxygen pressure and growth temperature effects on epitaxial growth of Er,03 are discussed. (c) 2005 Elsevier B.V. All rights reserved.