Advanced solid-phase crystallization for high-hole mobility (450 cm2 V−1 s−1) Ge thin film on insulator

The hole mobility of the solid-phase-crystallized Ge layer is significantly improved by controlling the deposition temperature of Ge (50–200 °C) and the Ge thickness (50–500 nm) and by applying post annealing at 500 °C. The resulting hole mobility — 450 cm2 V−1 s−1 — is the highest reported value to date among semiconductor layers directly formed on glass. The mechanism of the mobility enhancement is discussed from the perspective of three carrier scattering factors: grain boundary scattering, interface scattering, and impurity scattering. The high-hole mobility Ge layer formed via the simple fabrication process is useful for high-speed thin-film transistors.