Key Engineering Materials Vol. 1056

Abstract: Cumulative heavy-ion irradiation effects were investigated in a commercial 4H-SiC double trench MOSFET through a combination of cyclotron experiments and TCAD simulations. Devices were exposed to continuous ¹²⁴Xe³⁵⁺ ion strikes at a linear energy transfer (LET) of 63 MeV·cm²/mg under drain biases from 100 to 400 V. Experimental results revealed the onset of permanent drain and gate leakage at voltages as low as 200 V, with degradation rates increasing by several orders of magnitude at higher bias. Post-irradiation measurements confirmed trench oxide rupture and source leakage path formation, establishing single-event leakage current (SELC) as the dominant degradation mechanism. In contrast, TCAD simulations of isolated ion strikes predicted catastrophic single-event burnout (SEB) only at or above 250–300 V, highlighting the critical role of cumulative damage processes that are not captured in single-strike models. These findings demonstrate that permanent leakage-driven degradation effectively extends the SELC zone beyond conventional SEB thresholds, reducing the safe operating area of trench-based SiC MOSFETs. The results have significant implications for derating strategies in space applications, where current SEB-focused guidelines may underestimate vulnerability, and highlight the need for radiation-hardening by device design to ensure long-term reliability.

Abstract: In this study, we conducted in-situ measurements on a SiC JFET operational amplifier operating under gamma-ray irradiation. It shows that the radiation did not affect the output waveform or voltage gain, but shifted the output offset voltage. This shift may result mainly from holes generated by irradiation and trapped in the oxide layer, which modified the I-V characteristics of the level-shifting diodes. It can be compensated by applying bias voltage, and it may also be prevented by optimizing the diode structure and/or circuit topology.

Abstract: Radiation-hardened SiC power devices are essential to prevent leakage degradation and catastrophic failures such as SEE and SEB. Lateral device structures lower the risk of contact shorting by providing greater physical separation between conductive regions. Wider device geometries also improve radiation tolerance, as larger dimensions can accommodate charge buildup with less effect on device performance. In addition, RESURF structures enhance robustness by shifting the high electric field into the bulk, which reduces the impact of radiation-sensitive interface states on breakdown.