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

Han Yang,Shenglong Ran,Jian'An Wang,Shengdong Hu,Tao Liu

doi:10.1109/jeds.2020.3032649

Abstract

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 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 on,sp . The R 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 gd ) which is reduced by 52% and the switching loss is also reduced by 19%.

Highlights

I n recent years, the wide-bandgap material silicon carbide (SiC) has been widely used in semiconductor power devices because of its basic characteristics, and SiC MOSFET is one of the major devices in power systems[1]-[3]
In order to optimize the trade-off relationship between the breakdown voltage (BV) and specific on-resistance (Ron,sp), some technologies have been successfully developed in SiC MOSFET products
It is well know that the high electric field at the corner of trench influences the BV of the SiC trench MOSFETs[7][8]

Summary

INTRODUCTION

I n recent years, the wide-bandgap material silicon carbide (SiC) has been widely used in semiconductor power devices because of its basic characteristics, and SiC MOSFET is one of the major devices in power systems[1]-[3]. In order to optimize the trade-off relationship between the breakdown voltage (BV) and specific on-resistance (Ron,sp), some technologies have been successfully developed in SiC MOSFET products. It is well know that the high electric field at the corner of trench influences the BV of the SiC trench MOSFETs[7][8]. The high electric field in semiconductor will affect the endurance of the gate oxide material and lead to hot. Jian'an Wang are with the National Laboratory of Analogue Integrated Circuits, No 24 Research Institute of China Electronics Technology Group Corporation, Chongqing 400060, China

DEVICE STRUCTURE AND MECHANISM

RESULTS AND DISCUSSIONS

CONCLUSION