Double-Layered Ge Thin Films on Insulators Formed by an Al-Induced Layer-Exchange Process

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• 作者：Kaoru Toko ; Koki Nakazawa ; Noriyuki Saitoh ; Noriko Yoshizawa ; Noritaka Usami ; Takashi Suemasu
• 刊名：Crystal Growth & Design
• 出版年：2013
• 出版时间：September 4, 2013
• 年：2013
• 卷：13
• 期：9
• 页码：3908-3912
• 全文大小：426K
• 年卷期：v.13,no.9(September 4, 2013)
• ISSN：1528-7505

文摘

A large-grained (111)-oriented Ge thin film is achieved on a SiO₂ glass substrate using an Al-induced crystallization (AIC) technique. Low-temperature (350 掳C) AIC of an amorphous Ge thin film (50 nm thickness) resulted in a self-organized double-layered structure of polycrystalline Ge layers. The top Ge layer consisted of randomly oriented small grains (1 渭m diameter) with a high defect density; in contrast, the bottom Ge layer was of high quality. Based on the growth model, we annihilated the top Ge layer using preferential etching. The bared bottom Ge layer provided a (111)-oriented area fraction of 99% and an average grain size of 90 渭m. This Ge layer appears promising for use in Ge-based thin-film devices, as well as a heteroepitaxial seed layer for group III鈥揤 compound semiconductors, aligned nanowires, and other advanced materials.