Improving Current Density of 4H-SiC Junction Barrier Schottky Diode with Wide Trench Etching

Abstract

The 4H-SiC trench junction barrier Schottky (TJBS) diode was proposed in conjunction with a deep p(+) junction using a trench etching process in order to reduce the reverse leakage current in the off-state for high-voltage applications above 1200 V. However, the 4H-SiC TJBS could not improve the forward current density. Addressing this limitation in this paper, we propose a wide trench JBS (WTJBS) that improves the current density without increasing the reverse leakage current using a shallow and wide trench etching process. The wide trench etching of the WTJBS produces a deeper junction depth, similar to the TJBS, and expands the area of the Schottky junction in a limited cell-pitch space. Comparing the results of the fabricated samples under the same process conditions, the WTJBS was found to have an enhanced current density and a low leakage current as compared to the TJBS and the JBS. This study shows that by using a suitable trench etching process, we can improve the current density of the SiC SBD with a low leakage current.