The relationship of voltage variations in the third quadrant and the Schottky area ratios in a 4H-SiC SBD-embedded MOSFET

Abstract

Based on the measured and the TCAD simulation results, this paper provides a detailed description of the third quadrant characteristics of the Schottky barrier diode (SBD) embedded MOSFETs with different Schottky area ratios of 2.6 %, 5.3 %, and 14.7 %. As the Schottky area ratio increases, the shift of the third quadrant turn-on voltages of the MOSFETs influenced by the gate voltage decreases. The shift rates in the conventional MOSFET and SBD-embedded MOSFETs are from 57.2 % to 0 % when Vgs changes from 0 V to −4 V. The shift rate becomes 0 % when the Schottky area ratio is larger than 5.3 %. Simultaneously, the TCAD simulation results and the measured results indicate that the SBD-embedded MOSFETs can effectively suppress the conduction of the low barrier diode and the body diode.Furthermore, the SPICE models were built to explain the physics mechanisms. The fitting error between the measured and fitting results is as low as 1.3 % among the models with the different Schottky area ratios.