Electron channel mobility in silicon-doped Ga2O3 MOSFETs with a resistive buffer layer

Abstract

The electron mobility in depletion-mode lateral β-Ga2O3(010) metal–oxide–semiconductor field-effect transistors (MOSFETs) with an n-channel formed by Si-ion (Si+) implantation doping was extracted using low-field electrical measurements on FET structures. An undoped Ga2O3 buffer layer protected the channel against charge compensation by suppressing outdiffusion of deep Fe acceptors from the semi-insulating substrate. The molecular beam epitaxy growth temperature was identified as a key process parameter for eliminating parasitic conduction at the buffer/substrate growth interface. Devices with a resistive buffer showed room temperature channel mobilities of 90–100 cm2 V−1 s−1 at carrier concentrations of low- to mid-1017 cm−3, with small in-plane mobility anisotropy of 10–15% ascribable to anisotropic carrier scattering.