Low Leakage Current β-Ga₂O₃ Self-Aligned Trench Junction Barrier Schottky Diodes

We demonstrate the fabrication of $\beta $ -Ga2O3 self-aligned trench junction barrier Schottky (TJBS) diodes with a high breakdown voltage (BV) and suppressed reverse leakage current, in which the micrometer-deep trenches were formed using the Schottky anode metal as an etching mask and subsequently covered by a layer of p-type nickel oxide (NiO). High BVs of over 2 kV were achieved in small area devices ( $0.43\times 0.43$ mm2) while maintaining an ultralow reverse leakage current density of around $10^{-{5}}$ A/cm2 until breakdown. A TCAD simulation analysis revealed that the deep trenches covered with p-NiO can effectively reduce the surface electric field of the proposed device and provide sufficient p-shielding effects. Additionally, the packaged large-area $\beta $ -Ga2O3 TJBS diodes ( $3\times 3$ mm2) show a forward current ${I} _{F}$ and BV of 15 A/820 V. The results demonstrate that the self-aligned TJBS structure offers critical insights into reducing reverse leakage current and improving high current-handling capabilities in large-area devices.