Interfacial-oxide layer controlled Al-induced crystallization of Si _1-xGe_x (x: 0-1) on insulating substrate

The effects of interfacial oxide layers on the Al-induced crystallization (AIC) of amorphous Si_1-xGe_x (x: 0-1) films on an insulator at a low temperature (<500 °C) have been investigated. In the case of Si, the inversion of the Si/Al layers was achieved for samples with and without interfacial oxide layers between the Si and Al layers. In addition, it was found that the existence of interfacial oxide layers was required to obtain large grain (×100 μm) polycrystalline Si with a (111) orientation. However, in the case of SiGe, the interfacial oxide layers significantly retarded AIC growth. Consequently, layer exchange occurred inhomogenously, which resulted in inhomogenous crystallization even after a long annealing time (410 °C, 100 h). To solve this problem, the effects of interfacial oxide thickness on AIC growth were investigated. As a result, complete layer exchange was achieved for samples with the whole Ge fractions (x: 0-1) by controlling the air exposure time. A qualitative model is presented.