Forming Gas Annealing Characteristics of Germanium-on-Insulator Substrates

Large-area layer transfer of germanium-on-insulator (GeOI) substrates has been fabricated by ion-cut processes. Pseudo-MOSFET structure was employed to characterize interface trap density, interface fixed charge density, interface carrier mobility, and bulk carrier mobility of these GeOI substrates with various annealing conditions in forming gas ambient. High-temperature annealing in the vicinity of 500degC-600degC has shown the best carrier mobilities, with the interface trap density and the interface fixed charge density as low as 10¹⁰ q/cm². The extracted bulk hole mobility of the annealed GeOI is near 500 cm²/( V middots), which is higher than that of silicon [300 cm²/(V middots)] at the same doping concentration level.