Effect of Deposition Parameters on the Crystallinity of Evaporated Germanium Films

Abstract

The crystallinity of Ge films deposited on (111) Ge substrates in vacuum ambients <10−8 Torr has been investigated as a function of deposition rate, substrate temperature, thermal treatment of substrates, and background oxygen pressure. Polycrystalline and epitaxial films were obtained at temperatures up to 200° lower than reported by previous investigations, and thermal annealing of substrates at 600°C prior to deposition resulted in a minimum epitaxial temperature of 100°C. Oxygen ambients as low as 5×10−9 Torr have been found to impede crystal growth and increase epitaxial temperatures by 50°–75°C.