The crystallization of SiGe-heterostructure in which a thin Ge layer put between Si layers has been investigated. When the Ge layer is inside the Si layer, the crystallization phenomena are similar to those of SiGe alloy layer; Ge completely diffuses in Si layer during the crystallization. When the Ge layer is at the interface between the Si layer and the quartz substrate, significant enhancement of crystallization has been found. In this structure, decrease in surface free-energy increases the nucleation rate at the interface and causes anomalous localization of Ge at the interface. When the Ge layer is on the surface of the Si layer, the crystallization property is quite different from the other structures. The underlying Si layer has large and aligned grains when the furnace annealing is assisted by the laser-annealing.
A part of this work was carried out under the ASET program supported by NEDO, Japan.