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 β-Ga
₂
O
₃
. 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 BaTiO
₃
and a low- κ dielectric like SiO
₂
overlapped over the gate electrode. Using this strategy in β-(Al
_0.18
Ga
_0.82
)
₂
O
₃
/ Ga
₂
O
₃
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 μm along with an improved power figure of merit of 408 MW/cm
²
. The reported works shows the effectiveness of integrating extreme dielectric materials with ultra-wide band gap semiconductors in significantly improving breakdown performance.