High-Breakdown Depletion-Mode Ga_2O_3 MOSFETs with a Field Plate

摘要

This work presents single-crystal Ga_2O_3 metal-oxide-semiconductor field-effect transistors (MOSFETs) with a gate-connected field plate (FP) for substantial enhancement in off-state breakdown voltage (H_(br)). A SiO_2 dielectric was used to serve a dual functionality for FP mechanical support as well as device surface passivation. The device channels, formed by selective-area Si ion implantation doping of an undoped Ga_2O_3 epilayer, were electrically isolated by the highly resistive epilayer without mesa etching. Effective surface passivation and high Ga_2O_3 material quality contributed to the absence of drain current collapse. The transistors exhibited an off-state V_(br) of 755 V, a high drain current on/off ratio of over 109, and stable high temperature operation against 300°C thermal stress.