β-(Al0.18Ga0.82)2O3/Ga2O3 Double Heterojunction Transistor With Average Field of 5.5 MV/cm.

Maintaining high average fields between the gate and drain is imperative in achieving near theoretical performance in ultra-wide band gap semiconductors like $\beta $ -Ga2O3. In this letter we report on a field management strategy to reduce the peak electric field at the drain side corner of the gate by using a composite dielectric layer consisting of an extreme permittivity dielectric like BaTiO3 and a low- $\kappa $ dielectric like SiO2 overlapped over the gate electrode. Using this strategy in $\beta $ -(Al0.18Ga0.82)2O3/ Ga2O3 double heterojunction field effect transistor, we achieved a record average breakdown field of 5.5 MV/cm at a gate-drain spacing of $1.15~\mu \text{m}$ along with an improved power figure of merit of 408 MW/cm2. The reported works shows the effectiveness of integrating extreme dielectric materials with ultra-wide band gap semiconductors in significantly improving breakdown performance. [ABSTRACT FROM AUTHOR]