Influence of Radiation Environment Variability on Cumulative Heavy-Ion-Induced Leakage Current in SiC Power Devices

Silicon carbide (SiC) power devices may exhibit step increases in leakage current when exposed to heavy ions while biased in the OFF state. Estimating the magnitude of this phenomenon over time in the variable solar energetic particle environment represents a challenge, as the probability of occurrence and step sizes are widely variable. The Prediction of Solar particle Yields for Characterizing Integrating Circuits (PSYCHIC) code is used to generate potential environmental flux spectra. Using an existing method, leakage current increases during broad-beam irradiation are characterized by frequency and magnitude. In this article, these characterizations are applied to various environmental flux spectra to generate a range of cumulative leakage current increases. This process is repeated to produce distributions of leakage current increases that account for environmental variability and step size variability. Comparing the results for various operating voltages, mission durations, and shielding, it is shown that shielding thickness and operating voltage have a significant influence on the potential cumulative leakage current increase.