Recessed-Gate Enhancement-Mode beta-Ga2O3 MOSFETs

We report enhancement-mode beta-Ga2O3 (BGO) MOSFETs on a Si-doped homoepitaxial channel grown by molecular beam epitaxy. A gate recess process is used to partially remove the epitaxial channel under the 1-mu m gated region to fully deplete at V-GS = 0 V. BGO MOSFETs achieve drain current density near 40 mA/mm and I-ON/I-OFF ratio similar to 10(9) which is the highest reported for homoepitaxial normally-off BGO transistors. At V-GS = 0 V, a breakdown voltage of 198 and 505 V is achieved with the source-drain spacing of 3 and 8 mu m, respectively. The power switching figure of merits for dc conduction and dynamic switch losses meet or exceed the theoretical silicon limit and previously reported depletion-mode BGO transistors.