Recessed-Gate Enhancement-Mode $\beta $ -Ga2O3 MOSFETs

Abstract

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- $\mu \text{m}$ gated region to fully deplete at ${V}_{\textsf {GS}}= 0$ V. BGO MOSFETs achieve drain current density near 40 mA/mm and ${I}_{ \mathrm{\scriptscriptstyle ON}}/{I}_{ \mathrm{\scriptscriptstyle OFF}}$ ratio ~109 which is the highest reported for homoepitaxial normally-off BGO transistors. At ${V}_{\textsf {GS}}= \textsf {0}$ V, a breakdown voltage of 198 and 505 V is achieved with the source–drain spacing of 3 and $8~\mu \text{m}$ , 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.