Enhancement-mode Ga2O3 MOSFETs with Si-ion-implanted source and drain

Enhancement-mode β-Ga2O3 metal–oxide–semiconductor field-effect transistors with low series resistance were achieved by Si-ion implantation doping of the source/drain contacts and access regions. An unintentionally doped Ga2O3 channel with low background carrier concentration that was fully depleted at a gate bias of 0 V gave rise to a positive threshold voltage without additional constraints on the channel dimensions or device architecture. Transistors with a channel length of 4 µm delivered a maximum drain current density (IDS) of 1.4 mA/mm and an IDS on/off ratio near 106. Nonidealities associated with the Al2O3 gate dielectric as well as their impact on enhancement-mode device performance are discussed.