2.44 kV Ga2O3 vertical trench Schottky barrier diodes with very low reverse leakage current

High-performance $\beta$-Ga203 vertical trench Schottky barrier diodes (SBDs) are demonstrated on bulk Ga2O3 substrates with a halide vapor phase epitaxial layer. A breakdown voltage (BV) of 2.44 kV, Baliga's figure-of-merit (BV²/Ron) of 0.39 GW/cm² from DC measurements and 0.45 GW/cm² from pulsed measurements are achieved, all of which are the highest among $\beta$-Ga2O3-based power devices. A lowest reverse leakage current density below $1\ \mu \mathrm{A}/\text{cm}^{2}$ until breakdown is observed on devices with a fin width of $1-2\ \mu \mathrm{m}$, thanks to the reduced surface field (RESURF) effect provided by the trench SBD structure. The specific on-resistance is found to reduce with increasing area ratio of the fin-channels following a simple relationship. The reverse leakage current agrees well with simulated results considering the barrier tunneling and barrier height lowering effects. The breakdown of the devices is identified to happen at the trench bottom corner, where a maximum electric field over 5 MV/cm could be sustained. This work marks a significant step toward reaching the promise of a high figure-of-merit in $\beta$-Ga2O3.