Demonstration of an 1200V/20A 4H-SiC Multi-Step Trenched Junction Barrier Schottky Diode

Abstract

In this study, we have realized a novel 1200 V 4H-SiC Multi-step trenched junction barrier Schottky (MTJBS) diodes with ultra-low leakage current. The MTJBS diode substantially alleviates the tradeoff dilemma between forward voltage drop and blocking voltage, thus enabling a larger design window that effective reverse blocking and excellent forward conduction can be achieved at the same time. Design considerations and device performances of the Multi-step trenched JBS devices are compared with those of the conventional planar JBS diodes via numerical simulation and analyses. It is demonstrated that the shielding effect of the conventional structure under high voltage remain effective only when the junction spacing is narrow (n<2μm), while the surface electric field of 4H-SiC Multi-step trenched JBS diode is decreased significantly by the deep barrier shielding layer. The surface electric field is only 0.18–0.95 MV/cm2 for 4H-SiC Multi-step trenched JBS diode with a varied junction spacing from 1 to 3 μm. When the surface electric field reach 1MV/cm2, the junction spacing of Multi-step trenched JBS diode is wider to 3 μm in comparision with 0.7 μm junction spacing of the conventional JBS diodes. Moreover, first demonstration of the MTJBS prototype fabrication and device characterization are also detailed in this study. The reverse leakage current with the MTJBS structure has been reduced by 2 orders of magnitude compared to the conventional planar JBS structure.