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

Abstract

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 $1~\mu \text{m}$ -width body contact has been fabricated and tested. According to measurement results, peak reverse recovery current density ( $\text{j}_{\text {PR}}$ ) of the proposed SJ MOSFET (34.1A/cm2) is 25.2% lower than the conventional SJ MOSFET (45.6A/cm2). Reverse recovery energy loss ( $\text{E}_{\text {rr}}$ ) of the proposed SJ MOSFET is 0.94mJ/cm2 and is 39.4% lower than the conventional SJ MOSFET (1.55mJ/cm2). The specific on-resistance of the proposed device (18.2 $\text{m}\Omega \cdot \text {cm}^{\text {2}}$ ) is slightly higher than the counterpart SJ MOSFET (17.1 $\text{m}\Omega \cdot \text {cm}^{\text {2}}$ ) because of lower active MOS-gate density. However, input capacitor ( $\text{C}_{\text {iss}}$ ) and gate charge ( $\text{Q}_{\text {G}}$ ) of the proposed SJ MOSFET are reduced a lot for less active MOS-gates.