1.2-kV Low-Barrier 4H-SiC JBS Diodes by Virtue of P-Implants Across Dead Field of Current Flow

A low value of Schottky barrier height (SBH) (F-B) is highly desired to further reduce the power loss in 4H-SiC junction barrier Schottky (JBS) diodes; however, the reduced F-B results in serious leakage current (IR) when blocking high voltages. In this work, a tunable low FB of 0.92-0.98 eV with an ideal factor n = 1.02-1.03 was first realized through effectual rapid thermal annealing (RTA) methods and combined with a trench-assisted stage-style p-type implants taking advantage of dead region for cur-rent flow to resolve the IR issue. Numerical simulation demonstrated the superiority of this promising strategy in alleviating the Schottky interface electric field (E-S) and suppressing I-R without constraining the forward current flow. Based on this practical strategy, the fabricated device achieved one order of magnitude less IR at 25 degrees C and 220% enhancement of breakdown voltage (V-B) at 175 degrees C in contrast to the conventional low-barrier one. In addition, benefiting from the low FB, the device achieved an ultralow turn-on voltage of 0.47 eV and a remarkable forward voltage drop (V-F) of 1.36 V extracted at 20 A, indicating 14% lower conduction loss than the titanium-based JBS diodes with the same device configuration. This novel device structure incorporating low-barrier Schottky contact metal and trench-assisted stage-style p-implants (SPs) in the dead region of current flow suggests a promising way to develop more advanced 4H-SiC JBS diodes in the future.