Low temperature of formation of nickel germanide on crystalline germanium

Thin films of nickel germanide conveniently form at the relatively low temperature of 300C in a matter of minutes and at even lower temperatures over a longer time. Here we report on the formation of NiGe on crystalline germanium substrates at low temperatures (less than 300C). Ni films deposited on Ge substrates formed NiGe by heating the samples in an atmosphere nearly void of oxygen. Ni films of thickness 50 to 400nm were deposited on crystalline germanium and heat treatments undertaken on samples for time durations at different temperatures of 5 minutes to 12 hours. It was found that the thickness was not a significant factor and that NiGe formed in a few minutes for all thicknesses heated at 300 C. Long durations were required for the lowest temperature of formation.