Gate-recessed, laterally-scaled β-Ga<inf>2</inf>O<inf>3</inf> MOSFETs with high-voltage enhancement-mode operation

Beta-phase gallium oxide (Ga ₂ O ₃ ) is a promising wide bandgap semiconductor possessing a larger bandgap (~4.8 eV) and critical electric field strength (~8 MV/cm) than GaN and SiC [1]. Early metal-oxide-semiconductor field-effect transistors (MOSFETs) have shown promising depletion-mode operation with high critical field strength [2], high-current density [3] and high breakdown voltage [4]. On native substrates, enhancement-mode operation has been achieved with a gated unintentional doped channel [5] and fin-channels [6], the latter achieving 600-V normally-off breakdown voltage. However, both are limited to ~1 mA/mm or less. Here, we report a new enhancement-mode device achieved by gate recess with improved drain-current > 20 mA/mm and near 200-V breakdown for laterally scaled 3-μm source-drain distance (L _sd ).