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

We demonstrate the fabrication of β-Ga<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>3</roman></sub> 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 × 0.43 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sup>) while maintaining an ultralow reverse leakage current density of around 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-<roman>5</roman></sup> A/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sup> 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 β-Ga<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sub>O<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>3</roman></sub> TJBS diodes (3 × 3 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sup>) show a forward current <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>F</i></sub> 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.