High Carrier Mobility Sn-Doped Ge Thin-Films (< 50 nm) on Insulator by Interface-Modulated Solid-Phase Crystallization at Low-Temperature

Effects of introduction of a-Si under-layers on solid-phase crystallization of Sn-doped Ge on insulator have been investigated. By introduction of a-Si under-layers, energy barrier for carriers at grain-boundaries is significantly decreased. As a result, high carrier mobility of 200−300 cm 2 /Vs is realized for thin GeSn films (30−50 nm) grown with a-Si under-layers. This mobility is the highest among ever reported data for Ge and GeSn thin-films (≤50 nm) on insulator grown at low-temperatures (≤500°C).