Simulation study on 4H–SiC power devices with high-k dielectric FP terminations

Abstract

The reverse blocking characteristics of 4H–SiC power devices with high dielectric constant (k) materials field plate (FP) terminations have been investigated by numerical simulations in this paper. The study makes a comparison between the breakdown characteristics of 4H–SiC power devices with different FP dielectrics comprising silicon oxide (SiO2), silicon nitride (Si3N4) and hafnium oxide (HfO2). The results show that the high-k dielectrics FP can significantly relieve the electric field enhancement at the junction corners and enhance the breakdown voltage of devices. The breakdown voltage as high as 2249V, which reaches about close to more than 90% of theoretical value, is achieved in HfO2 FP terminated 4H–SiC Schottky barrier diode. The maximum electric field in the dielectric layer can be greatly reduced from 7MV/cm for SiO2 FP to 5.7MV/cm for Si3N4 FP and 3.6 MV/cm for HfO2 FP. Meanwhile, it also implies that the high-k dielectrics FP terminations can efficiently suppress the sensitivity of the breakdown voltage to the interface states and improve the devices reliability compared with the conventional SiO2 FP termination.