Effect of epitaxial buffer layer on SiC junction barrier Schottky diodes electrical performance degradation induced by heavy ions

Abstract

Silicon carbide (SiC) Junction-Barrier-Schottky (JBS) diodes are becoming increasingly important for high-power and high-radiation environments due to their superior material properties, including high voltage tolerance, fast switching speeds, and excellent resistance to radiation-induced damage. However, SiC devices are vulnerable to single-event effects (SEE), especially under heavy ion irradiation. Ion-induced generation of a large number of electron-hole pairs within the SiC material, coupled with the high electric field in the device’s depletion region, results in highly localized energy pulses and power dissipation. This leads to the radiation damage in the device material, ultimately causing degradation of the device’s electrical performance. This study investigates the impact of a Buffer structure with a graded doping profile on the single-event burnout (SEB) and single-event leakage current (SELC) thresholds of SiC JBS diodes. Heavy ion irradiation with different linear energy transfer (LET) values was used to assess the device performance under reverse bias conditions. The results show that the Buffer structure significantly improves the SEB threshold compared to the Baseline structure, reducing the risk of breakdown under high LET irradiation. Additionally, the study uses TCAD simulations to analyse the influence of LET and bias voltage on power dissipation and electric field distribution, revealing that the Buffer structure mitigates high electric field concentrations, it enhances the device’s resistance to SELC and SEB by modulating the electric field distribution and reducing power density peaks at specific locations within the device.