Sub-Micron Gallium Oxide Radio Frequency Field-Effect Transistors

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 f(t)/f(max) = 3/13 GHz at V-DS = 40 V. The second approach uses a thin and higher doped channel with a T-gate formed by electron beam lithography. An f(t)/f(max) = 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.