Sub-Micron Gallium Oxide Radio Frequency Field-Effect Transistors

Abstract

Beta-gallium oxide (BGO) radio frequency device performance is presented using sub-micron T-shaped gates. In the first design, a gate-recess is implemented to allow gate and channel device scaling which results in $\text{f}_{\mathbf {t}} {/\mathbf {f}} _{\mathbf {max}} \quad =$ 3/13 GHz at $\text{V}_{\mathbf {DS}} \quad =$ 40 V. The second approach uses a thin and higher doped channel with a T-gate formed by electron beam lithography. An $\text{f}_{\mathbf {t}} {/\mathbf {f}} _{\mathbf {max}} \quad =$ 5/17 GHz is measured at ${V}_{DS} =$ 15 V and is the highest reported for BGO transistors. Significant gains in RF performance are expected with reduction of device parasitics and vertically scaled epitaxial designs.