Metal-induced low-temperature crystallization of electrodeposited Ge thin film

Metal-induced crystallization was applied to an electrodeposited Ge film on an insulator. It was confirmed that crystallization occurred at 150 °C for 1 h in ambient N2 and that Cu, which was used as an electrode for plating, started diffusing into the Ge film even at 100 °C. The diffused Cu was distributed uniformly in the film, and the ratio of Cu to Ge was ∼2.5. A fine particulate pattern, attributed to the effect of the Cu diffusion, was observed on the surface by scanning electron microscopy. We considered that the crystallization of the electrodeposited Ge occurred because of the diffusion of Cu from the electroplate electrode. Consequently, (220)-oriented Ge was obtained. The maximum grain size of the crystallized 120-nm-thick Ge film was 240 nm.