Epitaxial Ge-Sb-Te phase change memory materials were fabricated by solid source molecular beam epitaxy. Reflection high-energy electron diffraction and X-ray diffraction reveal a face centred cubic structure of the films with lattice constants of 6.01 +/- 0.02 angstrom close to that reported for the metastable cubic phase of Ge2Sb2Te5. The layers grow in amorphous, polycrystalline or epitaxial form depending on the substrate temperature in the range from 20 to 370 degrees C. Composition analysis confirms the 2:2:5 ratio for Ge, Sb and Te. We find a resistance drop upon crystallization from the amorphous phase as big as six orders of magnitude. (c) 2008 Elsevier B.V. All rights reserved.