Simulation studies of Single Event Effects in Ga$_2$O$_3$ MOSFETs

TL;DR

This study uses 2D simulations to analyze Single Event Burnout in Ga2O3 MOSFETs, proposing radiation-hardened designs with high-k dielectrics to improve voltage thresholds under extreme radiation.

Contribution

It introduces novel radiation-hardened Ga2O3 MOSFET designs using high-k dielectrics, significantly increasing SEB thresholds beyond current technologies.

Findings

High electric fields cause SEB in Ga2O3 MOSFETs.

HfO2-SiO2 dielectric combination raises SEB threshold to 550V.

BaTiO3-SiO2 dielectric achieves thresholds up to 1000V.

Abstract

In this article, we investigate the Single Events Effects (SEE) leading to Single Event Burnout (SEB) in $\beta$-Ga$_2$O$_3$ MOSFETs. Using Silvaco TCAD, 2D simulations were performed to understand the mechanism behind the SEB mechanism in lateral Ga$_2$O$_3$ MOSFETS. The high electric fields in the channel played a critical role leading to high impact generation rates and eventual SEB. To reduce the electric field in the channel, radiation hardened designs are then proposed with rounded gates and the use of a combination of high permittivity (k) dielectric with SiO$_2$. With HfO$_2$-SiO$_2$ dielectric combination, the SEB threshold of 550V at LET=10 MeV/mg/cm$^2$ is seen. However, to operate under extreme radiation conditions, a combination of very high-k dielectric material BaTiO$_3$ with SiO$_2$ is proposed. Using the radiation hardened design, SEB thresholds up to 1000 V for LET=75 MeV/mg/cm$^2$ could be achieved which is higher than the state-of-the-art technology. The energy dissipated during the ion strike event is also calculated and it is observed that it is lower than that of SiC MOSFETs.