Split gate resurf stepped oxide UMOSFET with p-pillar for improved performance

Abstract

In this work, the authors propose a split-gate resurf stepped oxide with P-pillar (SGRSOP) UMOS structure. The Ppillar trench under the source electrode in SGRSOP U-shape metal-oxide-semiconductor (UMOS) serves the purpose of simultaneously achieving the following: (1) it has formed a local super junction (SJ) structure with the N-type drift. The Ppillar modulates the electric field distribution in the local SJ and increases the N-drift region doping concentration. (2) It has suppressed the parasitic bipolar junction transistor (BJT) effect by adding the P-pillar in the N-drift region, enlarges the boundary of the snapback. As compared with the SGRSO UMOS, the SGRSOP UMOS only add the P-pillar structure, while it has the better performance. The simulation results show that the SGRSOP UMOS reduces the on-state specific resistance (RSP) and increases the transconductance (gm), improves the figure of merit and its UIS ruggedness is as good as that of the split-gate resurf stepped oxide UMOS. © The Institution of Engineering and Technology 2014.