【Member Papers】Catastrophic burnout mechanisms of NiO/β-Ga₂O₃ heterojunction diodes irradiated by 1.35 GeV high-energy heavy ions

      Researchers from the Harbin Institute of Technology and Nanjing University have published a dissertation titled "Catastrophic burnout mechanisms of NiO/β-Ga₂O₃ heterojunction diodes irradiated by 1.35 GeV high-energy heavy ions" in Applied Physics Letters.

Project Support

      This work was supported by the National Key R&D Program of China (Nos. 2022YFB3605403 and 2023YFA1609000), the Jiangsu Provincial Key Research and Development Program of China (Nos. BE2023007-4 and BK20232045), the National Natural Science Foundation of China (Nos. 12075069, 12275061, 62304102, 62374084, 62234007, 62293522, U21A20503, and U21A2071), the State Key Laboratory of Space Environment Interaction with Matters, and the Guangdong Basic and Applied Basic Research Foundation under Grant No. 2025A1515011965. 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 irradiation support.

Background

      Ultra-wide bandgap beta-phase gallium oxide (β-Ga₂O₃) has attracted significant interest in aerospace electronics applications due to its exceptional material properties, including a high threshold displacement energy and a large breakdown electric field (E-field). In the space radiation environment, heavy ions originating from high-energy collisions of cosmic rays, solar flares, and coronal mass ejections pose a critical threat by accelerating device degradation and even causing catastrophic burnout. The linear energy transfer (LET), representing the energy deposited by heavy ions at a specific depth in the device, is a crucial metric outlined in the JEDEC standard for evaluating radiation hardness. Devices typically require tolerance to LET values as high as 75 MeV·cm²/mg. Achieving such exposure involves high-energy heavy ions like Ta ions, which are available only at a few global irradiation facilities. Limited access to these resources restricts a comprehensive understanding of the irradiation response and durability of the emerging Ga₂O₃ power devices, leaving this area of research still in progress.

Abstract

      Ultra-wide bandgap beta-phase gallium oxide (β-Ga₂O₃) power devices hold great promise in space applications; however, their intrinsic vulnerability to heavy ion irradiation, particularly defect behavior and catastrophic burnout mechanisms, remains largely unexplored. By performing bias voltage-dependent multiple rounds of statistical experiments with 1.35 GeV high-energy Ta ion irradiation, this work identifies electron and hole traps before burnout in NiO/β-Ga₂O₃ heterojunction diodes (HJDs), among which the introduced hole trap H2 (E_V + 0.6 eV, 2.9 × 10¹³ cm⁻³) is revealed to dominate the irrecoverable leakage degradation associated with device damage by deteriorating the junction barrier. This trap in Ga₂O₃ is attributed to the electron energy loss along the ion incidence trajectory based on the “thermal spike” physics theory, possibly resulting in a localized amorphous latent track. Beyond device damage, the catastrophic burnout in irradiated HJD is identified in two distinct regions: Region I (p-NiO/n⁻-Ga₂O₃) dominated by trap-assisted electric field breakdown, and Region II (n⁻-Ga₂O₃/n⁺-Ga₂O₃) characterized by thermally driven damage from charge accumulation. Additionally, thermal effects also impact the active area of Region I along the carrier dissipation pathway. These findings provide insight into the damage and failure physics of β-Ga₂O₃ devices under heavy-ion strikes and inform strategies for improved irradiation hardness.