界面酸化膜挿入型Au誘起層交換成長法による大粒径Ge(111)/絶縁膜の低温成長: 界面酸化膜厚依存性

A technique for low-temperature(<〜350℃) formation of orientation-controlled large-grain Ge films on insulating layers is desirable for realization of flexible high-speed thin film transistors. In line with this, we have investigated Au-induced layer-exchange crystallization using a-Ge/Au/insulator stacked structures where Al_2O_3 layers were inserted at a-Ge/Au interfaces. Consequently, (111)-oriented large-grain (20-50 μm) films are obtained by inserting the interfacial layers (〜3 μm). These phenomena are explained based on the retardation of random bulk nucleation in Au films and thus domination of(111)-oriented nucleation on insulators, caused by suppression of Ge/Au interdiffusion.