Germanium thin film formation by low-pressure chemical vapor deposition

Thin films of polycrystalline germanium were formed by the pyrolysis of germane gas in a low-pressure reactor. Process parameters investigated were deposition temperature in the range 250 to 350 degrees C and pressure in the range 300 to 600 mTorr. The properties of the film have been characterized using transmission electron microscopy and x-ray diffraction for structural analysis, atomic force microscopy for surface morphology analysis, secondary ion mass spectroscopy for compositional analysis, and Hall effect measurement for electrical parameter extraction, etc. High Hall effect mobility on the order of 300 cm(2)/V s was obtained, even at a relatively low deposition temperature of 300 degrees. This makes the germanium thin films potentially very promising for low-temperature device processing.