Mobility characterization of Ge-on-insulator metal-oxide-semiconductor field-effect transistors with striped Ge channels fabricated by lateral liquid-phase epitaxy

High-mobility metal-oxide-semiconductor field-effect transistors (MOSFETs) consisting of stripe-shaped local germanium-on-insulator (GOI) structures were fabricated by lateral liquid-phase epitaxy (LLPE). The effective hole mobility of back-gate LLPE-grown GOI MOSFETs was accurately and reliably evaluated with a split capacitance-voltage (C-V) method. The superior effective hole mobility of the GOI devices throughout a wide range of accumulated carrier densities over that for a reference silicon-on-insulator device was demonstrated. A very high peak hole mobility of 511 cm2/Vs and an on/off current ratio of 106, together with phonon scattering limited carrier mobility at high temperatures, indicated not only the excellent crystalline quality of LLPE-grown GOI but also surprisingly good interface quality between Ge and the buried oxide.