The reverse recovery characteristics of an SiC superjunction MOSFET with a p-type Schottky diode embedded at the drain side for improved reliability

摘要

The improvement achieved in the reverse recovery characteristics of an SiC superjunction metal-oxide-semiconductor field-effect transistor (MOSFET) by embedding a p-type Schottky contact at the drain terminal and removing the N++ substrate is presented. The carrier injection into the drain terminal during the reverse recovery phase is drastically reduced in the proposed device due to the Schottky barrier, thereby eliminating the need for an external free-wheeling diode. The calibrated two-dimensional (2D) numerical simulations using Synopsys technology computer-aided design (TCAD) software reveal an improvement in (i) the reverse recovery charge by 70%, (ii) the switching loss due to reverse recovery by 70%, and (iii) Baliga's figure of merit (FOM) by 4.5% compared with the device without the Schottky contact. Furthermore, the variation in the device and circuit characteristics is analyzed from 300 to 500 K using nonisothermal simulations.