Fabrication of a 650V Superjunction MOSFET With Built-in MOS-Channel Diode for Fast Reverse Recovery

In this letter, a 650V superjunction (SJ) MOSFET with a built-in MOS-channel diode for fast reverse recovery is proposed and fabricated. Simulations on the new device via Sentaurus TCAD are first made. For the proposed device, a body contact is employed to restrain the parasitic PN diode and the reverse recovery characteristics can be modulated by varying the body contact width. The proposed device with 1 μm-width body contact has been fabricated and tested. According to measurement results, peak reverse recovery current density (jPR) of the proposed SJ MOSFET (34.1A/cm ² ) is 25.2% lower than the conventional SJ MOSFET (45.6A/cm ² ). Reverse recovery energy loss (Err) of the proposed SJ MOSFET is 0.94mJ/cm ² and is 39.4% lower than the conventional SJ MOSFET (1.55mJ/cm ² ). The specific on-resistance of the proposed device (18.2 mQ · cm ² ) is slightly higher than the counterpart SJ MOSFET (17.1 mQ · cm ² ) because of lower active MOS-gate density. However, input capacitor (Ciss) and gate charge (QG) of the proposed SJ MOSFET are reduced a lot for less active MOS-gates.