Abstract
Heteroepitaxial growth of bcc metallic alloys or a high-k insulator on Ge(111) has been explored for next generation Ge-based devices. First, we introduce a finely controlled crystal growth technique of bcc-type ferromagnetic alloys on Ge(111). Next, we show that the Fermi level pinning is significantly suppressed at the high-quality bcc-alloys/Ge heterointerfaces. Using these kinds of structures, we can achieve spin injection and detection in n-Ge. Finally, we present a new approach to gate-stack structures for Ge-MOSFET. Even a crystalline high-k insulator can be grown epitaxially on Ge(111) and a high-quality heterointerface can be achieved. Also, reasonable electrical characteristics are obtained. These finely controlled heterointerfaces will open a way for developing new technologies in next generation Ge-based devices with low power consumption.