Electrostatic Engineering of β-Ga2O3 Trench Metal–Insulator–Semiconductor Schottky Barrier Diodes Using a Bilayer Dielectric Stack

We predict improved electrostatic fields in a $\beta $ -Ga2O3trench metal–insulator–semiconductor (MIS) Schottky barrier diode (SBD) by integrating a bilayer dielectric as the insulator layer. The bilayer leverages the benefits offered by a high- ${K}$ /low- ${K}$ dielectric arrangement to obtain lower gate leakage as well as alleviated peak fields compared with a stand-alone dielectric insulator. Through detailed 2-D simulations of geometrically optimized MIS trench SBDs, electrostatic engineering of the bilayer dielectric device is performed to predict better breakdown characteristics and the initiation of impact ionization, which is a measure of the intrinsic capability of the material, at comparatively higher doping of the drift layer, as well as a higher power figure-of-merit (FoM; ≈4 GW/cm2) compared with single-layer dielectric insulators.