Abstract:
In this paper, a novel 10 kV SiC MOSFET embedding low barrier diode (LBD-MOSFET) is proposed and researched to solve the bipolar degradation effect in SiC MOSFET. The low barrier diode (LBD) in the cell is formed by introducing an N_well above the P_base region on one side, which reduces the electron barrier between the drain and the source. When the LBD-MOSFET works in the third quadrant, the low electronic barrier makes the LBD turn on with a lower source-drain voltage, thus effectively avoiding the bipolar degradation effect caused by the turn-on of the body diode. 2D numerical analysis results show that the breakdown voltage of the SiC LBD-MOSFET reaches 13.5 kV. In the third quadrant, the turn-on voltage is only 1.3 V, which is 48% lower than the traditional structure and effectively reduces the conduction loss of the device. At the same time, since the gate-drain overlap area of the LBD-MOSFET is reduced compared to the traditional MOSFET, the
Cgd is only 1.0 pF/cm
2 and the high-frequency merit value of the device is 194 mΩ·pF, which are reduced by 81% and 76% compared with the traditional MOSFET, respectively. Therefore, the LBD-MOSFET is suitable for high-frequency and high-reliability power electronic systems.