Carrier removal rates in 4H–SiC power diodes – A predictive analytical model

Abstract

An analytical model for predicting the proton and neutron radiation-induced carrier removal in silicon carbide (4H–SiC) diodes, is developed. It is primarily aimed towards a fast calculation of the carrier removal rates (ηe) and critical fluence (above which the diode drift layer is fully compensated), for a wide range of particle energies and diode ratings. The model utilizes the NIEL (non-ionizing energy loss) concept along with the actual carrier removal rate values for SiC available in the literature. A comparison to Si power devices is also made. The results from the predictive model suggest that diodes with a lower voltage rating can sustain a higher particle fluence and displacement damage before their drift layers are fully compensated. This provides radiation hardening guidelines for 4H–SiC power diodes at a device engineering level, which can help improve the reliability of circuits in harsh environment applications, such as space. The model is validated through TCAD simulations incorporating the proton-induced defects, as well as experimentally by irradiating SiC diodes with 2 MeV protons. The extracted compensation levels are in good agreement with those predicted by the analytical model, validating its potential in predicting carrier removal rate of SiC diodes for radiation prone environments.