A chemical vapor deposition method provides a smooth continuous germanium film layer, which is deposited on a metallic substrate at a sufficiently lower temperature to provide a germanium device suitable for use with temperature sensitive materials such as aluminum and copper. Another chemical vapor deposition method provides a smooth continuous silicon germanium film layer, which is deposited on a silicon dioxide substrate at a sufficiently low temperature to provide a germanium device suitable for use with temperature sensitive materials such as aluminum, copper and chalcogenides memory materials.