Epitaxial (001) Ge on Crystalline Oxide Grown on (001) Si

Fully epitaxial germanium-on-insulator structures have been grown for the first time on (001) Si substrates by using a perovskite oxide template. Detailed transmission electron microscopy analysis revealed that a two-temperature growth procedure is required in order to avoid three-dimensional island growth and to obtain continuous and flat Ge films. The interface between the oxide and Ge is fully crystalline and atomically sharp. A high density of stacking faults and twin structures has been found preferentially originating from the surface roughness of the oxide.