【Domestic Papers】Single-event burnout in β-Ga₂O₃ Schottky barrier diode induced by heavy ion irradiation

      Researchers from the China Electronic Product Reliability and Environmental Testing Research Institute have published a dissertation titled "Single-event burnout in β-Ga₂O₃ Schottky barrier diode induced by heavy ion irradiation" in Applied Physics Letters.

Project Support

      This work was supported in part by the National Natural Science Foundation of China under Grant No. 12305299 and in part by the Xinjiang Uygur Autonomous Region 2023 “Tianchi YingCai Program” under Grant No. 2024000057.

Background

      Beta-phase gallium oxide (β-Ga₂O₃) has attracted significant attention for electronic device applications due to its outstanding material properties. With an ultra-wide bandgap of 4.9 eV and a high critical electric field strength of up to 8 MV/cm, β-Ga₂O₃ offers remarkable advantages for high-temperature and high-power electronic devices, such as power rectifiers, deep-ultraviolet photodetectors, and metal–oxide–semiconductor field-effect transistors (MOSFETs). In addition, β-Ga₂O₃ can be grown by melt-based methods, which are more cost-effective than those used for SiC and GaN, further promoting its development in high-power electronics.

Abstract

      This study investigates single-event burnout (SEB) effects in β-Ga₂O₃ Schottky barrier diodes under heavy ion irradiation. Bi, Ta, and Kr ions with linear energy transfer (LET) values of 99.7, 75, and 37 MeV/(mg·cm²), respectively, were used in the experiments. The results show that the SEB threshold voltage decreases with increasing LET, indicating a strong dependence on energy deposition. In addition, reverse bias is identified as a critical triggering condition for SEB, which occurs only when the applied voltage is high enough to initiate thermal runaway and cause irreversible damage. To further elucidate the failure mechanism, Kr ions were selected for detailed investigation. technology computer-aided design simulations combined with scanning electron microscopy-based failure analysis revealed that transient current surges can rapidly elevate the local temperature. Once the temperature reaches the melting point of Ga₂O₃ material, SEB is triggered by irreversible thermal failure. Moreover, the failure sites were primarily located at the edge of the Schottky junction, indicating structural vulnerability in this region. These findings clarify the LET and reverse bias dependence of SEB in ultra-wide bandgap devices and provide insights into radiation-hardened design.

Conclusion

      In summary, this study systematically investigates the physical mechanism of SEB induced by heavy ion irradiation in b-Ga₂O₃ SBD by combining experimental testing with TCAD simulations under various LET conditions. The results show that SEB triggering depends not only on the LET of the incident ions but also strongly on the magnitude of the applied reverse bias. High-LET ions tend to induce SEB at lower voltages due to concentrated energy deposition, while lowerLET ions require higher bias to reach the critical failure threshold. The EMMI analysis confirms that the burnout site is located at the edge of the Schottky junction. Further FIB-SEM analysis reveals that the thermal runaway during the SEB process causes catastrophic structural damage, extending beyond the epitaxial layer and partially into the substrate, resulting in a distinct vertical burnout path. These findings provide insights for improving the thermal robustness and radiation tolerance of Ga₂O₃-based power devices operating in harsh environments.