Effect of trench structure on reverse characteristics of 4H-SiC junction barrier Schottky diodes

We investigated 4H-SiC trench junction barrier Schottky (JBS) diodes from the viewpoints of the tradeoff between the electric field at the Schottky contact interface (E s) and the forward voltage drop, the effect on reduction of reverse leakage current, and the device yield. By calculating E s, we found that the trench JBS structure can make E s one order of magnitude smaller than that of the planar JBS structure, when the bevel angle (θ) is set between 80 and 90°. Moreover, 600 V/50 A trench JBS diodes were fabricated, and their reverse leakage current at 600 V was made 102 times smaller than that of the planar JBS diode by effectively reducing E s. We also found that this reduction in reverse leakage current decreases the number of low breakdown voltage samples below 600 V and improves the yield.