Structural and electrical properties of Ge(111) films grown on Si(111) substrates and application to Ge(111)-on-Insulator

• A high-quality Ge layer is epitaxially grown on a Si(111) by two-step growth manner.
• Growth conditions, such as growth temperatures, are optimized.
• Very high hole mobility is obtained from Ge(111) grown on Si(111).
• High-quality thin Ge-on-Insulator with (111) orientation is obtained.

Structural and electrical properties of a Ge(111) layer directly grown on a Si(111) substrate are studied. Via optimized two-step growth manner, we form a high-quality relaxed Ge layer, where strain-relieving dislocations are confined close to a Ge/Si interface. Consequently, a density of holes, which unintentionally come from crystal defects, is highly suppressed below 4 × 1016 cm− 3, which leads to significantly high hole Hall mobility exceeding 1500 cm2/Vs at room temperature. By layer transfer of the grown Ge layer, we also fabricate a Ge(111)-on-Insulator, which is a promising template for high-performance Ge-based electronic and photonic devices.