1.5 kV Vertical Ga2O3 Trench-MIS Schottky Barrier Diodes

Abstract

$\beta-\mathrm{Ga}_{2}\mathrm{O}_{3}$ electronic devices for high power applications have seen rapid development over the recent years, due to the excellent material properties including an extremely large band-gap, high critical electric field, decent electron mobility and the availability of low-cost bulk substrates. As unipolar devices, Ga2O3 vertical Schottky barrier diodes (SBDs) have fast switching capability, while enjoying all the superior properties of Ga2O3. With the development of halide vapor phase epitaxy (HVPE) capable of delivering high quality thick n– epitaxial layers [1], $\mathrm{Ga}_{2}\mathrm{O}_{3}$ vertical SBDs have shown promising results with up to 1 kV breakdown voltage (BV) together with decent on-resistance $(\mathrm{R}_{\mathrm{on}})$ of $2-6\ \mathrm{m}\Omega\cdot \mathrm{cm}^{2}\ [1-3]$. However, the results are still far from the projected performance which surpasses GaN and SiC [4]. One important reason is the high reverse leakage current due to the high surface electric field, which causes thermionic-field emission and barrier height lowering, especially at the device edge where field crowding occurs. The leakage current can be much reduced by edge termination techniques such as field-plating [3]. More effectively, a trench-metal-insulator-semiconductor (MIS) structure can be utilized to reduce the leakage current [5], taking advantage of the reduced surface field (RESURF) effect [6]. In this work, we demonstrate Ga2O3 trench-MIS SBDs with a record-high 1.5 kV breakdown voltage without edge termination, together with a ~104 times reduction in reverse leakage current compared with regular SBDs.