A series of Al-Ge thin films, with varying overall compositions, were codeposited in a radio frequency inductively coupled plasma assisted hybrid chemical/physical vapor deposition system. Detailed compositional and structural characterization of sputter co-deposited Al-Ge thin films was carried out using X-ray photoelectron spectroscopy. energy dispersive X-ray spectroscopy, scanning electron microscopy, and transmission electron microscopy (TEM). Ge crystallization and Al-Ge phase separation in as-deposited Al-Ge thin films were studied by high-resolution TEM. The present study reveals some details regarding the process of Al-Ge phase separation during thin film deposition. (C) 2010 Elsevier B.V. All rights reserved.