A very low temperature single crystal germanium growth process on insulating substrate using Ni-induced lateral crystallization for three-dimensional integrated circuits

Metal (Ni)-induced lateral crystallization (MILC) of amorphous (α) -germanium (Ge) films on silicon dioxide (Si O2) is investigated on α-Ge planar films, annealing at 350-380 °C in a N2 ambient. MILC is not observed after annealing for 1 h at 350 °C, and self-nucleation with its small, deleterious microcrystals plagues the process at 380 °C. 360 °C is determined to be an optimum annealing temperature. These conditions are subsequently applied to a patterned nanowire to obtain a single-crystal Ge wire on Si O2. The method is promising for integrating high quality Ge transistors at low temperatures as required by three-dimensional integrated circuits.