Simulative Researching of a 1200V SiC Trench MOSFET With an Enhanced Vertical RESURF Effect

A SiC trench MOSFET with an enhanced vertical RESURF effect is proposed and analyzed in this article. The device features a deep oxide trench surrounded by a P-type doping layer at the source-side. With the assistant depletion effect of the P-type layer, the concentration of the N-drift region is increased and the specific on-resistance ( {R} _{\mathrm{ on,sp}} ) is thus reduced. The P-type doping can significantly reduce the intensity of the electric field at the gate oxide corner, and modulate the bulk electric field for the device. The breakdown voltage ( BV ) is therefore improved. As a result, the proposed SiC MOSFET has a better trade-off of BV and {R} _{\mathrm{ on,sp}} . The {R} _{\mathrm{ on,sp}} decreases by 59% and the BV increases by 16% for the proposed device without a CSL layer compared with the conventional trench MOSFET with a CSL layer. Meanwhile, the device exhibits a lower gate-to-drain charge ( {Q} _{\mathrm{ gd}} ) which is reduced by 52% and the switching loss is also reduced by 19%.