First Demonstration of Trench-shaped 6.5-kV n-channel SiC IGBT with Trench-etched Double-diffused MOS (TED-MOS) Structure

We report the first experimental demonstration of trench-shaped 6.5-kV SiC IGBTs. The trench-etched double-diffused MOS (TED-MOS) structure was employed to improve the electron injection from the emitter due to its fin-shaped gate channel while keeping the electric field of a gate oxide sufficiently low. The SiC IGBT with the TED-MOS structure had an on-voltage of 4.8 V at the collector current of 200 A/cm
²
at 25 °C. The specific differential on-resistance at this point was 6.6 mΩ•cm
²
, which was around three times lower than that of the conventional planar-gate device. It also had a smaller feedback capacitance, leading to a reduction of the turn-off loss. The turn-on loss was also reduced due to the electron injection enhancement. The SiC IGBT exhibited both a lower on-voltage and switching loss by utilizing the TED-MOS structure.