【Domestic Papers】1.4-kV Irradiation-Hardened β-Ga₂O₃ Heterojunction Barrier Schottky Diode Under 10⁷ ions/cm² Fluence and 82.1 MeV⋅cm²/mg LET Environments

      Researchers from the Nanjing University have published a dissertation titled "1.4-kV Irradiation-Hardened β-Ga₂O₃ Heterojunction Barrier Schottky Diode Under 10⁷ ions/cm² Fluence and 82.1 MeV⋅cm²/mg LET Environments " in IEEE Electron Device Letters.

Project Support

      This work was supported in part by the National Key Research and Development Program of China under Grant 2022YFB3605403; in part by Jiangsu Provincial Science and Technology Major Project under Grant BG2024030; in part by Jiangsu Provincial Key Research and Development Program of China under Grant BE2023007-4 and Grant BK20232045; in part by the National Natural Science Foundation of China under Grant 62425403, Grant 62234007, Grant 62293522, Grant 62304102, Grant U21A2071, and Grant U21A20503; and in part by the Open Foundation of Key Laboratory of Laser Devices and Technology of China North Industries Group Company Ltd. under Grant KLLDT202303.

      The authors would like to thank the Space Environment Simulation Research Infrastructure (SESRI) and the Frontiers Science Center for Matter Behave in Space Environment of Harbin Institute of Technology for providing the irradiation facilities and technical support.

Background

      Ultrawide bandgap neta-gallium oxide (UWBG β-Ga₂O₃) has garnered significant attention for aerospace electronic systems thanks to its superior material properties, particularly its high threshold displacement energy of lattice atoms. This property makes β-Ga₂O₃ devices inherently more resistant to radiation-induced displacement damage. To exploit the irradiation tolerance of β-Ga₂O₃ devices researchers have utilized heavy ions with energies spanning from MeV (germanium, Ge ions) to GeV (tantalum, Ta ions), replicating the harsh conditions of the space environment. However, catastrophic single-event burnout (SEB), characterized by significant derating of breakdown voltage (BV) under irradiation remains a critical 38 challenge. Currently, 1.1-kV β-Ga₂O₃ power diodes exhibit SEB voltages of only 150∼250 V under irradiation, which is insufficient for high-voltage aerospace applications.

Abstract

      Single event burnout (SEB) caused by heavy ion irradiation in space environments poses a significant threat to aerospace power electronic devices. This work demonstrates irradiation-hardened β -Ga₂O₃ heterojunction barrier Schottky (HJBS) diodes with exceptional SEB capability. The device design incorporates micron-scale deep trenches filled by p-type nickel oxide (NiO) and high-k BaTiO3 field-plate (FP) edge termination. This architecture efficiently extracts radiation-induced positive charges (holes) during single-event irradiation through the trenched-embedded Ni/p-NiO with low Ohmic contact resistance, significantly alleviating charge aggregation while minimizing non-uniform field distributions through strategically engineered charge drainage pathways. As a result, the HJBS device achieves a SEB voltage exceeding 1.4 kV and a SEB degradation rate of only 9.6%. This is the first demonstration of kilovolt-class radiation-hardened diodes, and its performance metrics are the best reported among SiC, GaN, Ga₂O₃ and Si power diodes to date. This work underscores the great potential of Ga₂O₃ power diodes for irradiation power applications.

Conclusion

      The NiO/β-Ga₂O₃ HJBS demonstrates robust radiation tolerance through synergistic design: low-resistance Ni/NiO-filled trenches enable efficient hole charge dissipation, while BaTiO₃ field plates mitigate edge electric field crowding. This optimized architecture achieves a record-high V_SEB of 1436 V and a low SEB degradation rate of 9.6% after 10⁷ heavy-ion strikes at 82.1 MeV·cm²/mg, highlighting the potential of β-Ga₂O₃ for radiation-hardened power electronics in extreme environments.