Study on the single-event burnout mechanism of <i>β-</i> Ga2O3 heterojunction diodes under heavy-ion irradiation

In this Letter, the single-event burnout (SEB) mechanism of β-Ga2O3 heterojunction diodes (HJDs) under irradiation with 1260 MeV krypton (Kr) ions has been investigated. A typical SEB phenomenon was observed when the reverse bias voltage reached 350 V. To elucidate the underlying mechanism of SEB, a local lattice temperature peak induced by impact ionization under high electric fields was proposed. SEB occurs when the peak lattice temperature exceeds the melting point of the β-Ga2O3 material. A lock-in infrared thermal imaging and scanning electron microscope (SEM) were employed to precisely locate leakage and microscopic damage within the device, respectively. The results indicate that devices exhibiting the SEB phenomenon have obvious leakage points, with visible holes within the drift region. The results of the scanning transmission electron microscopy analysis indicate that latent tracks are formed along the ion trajectory within the β-Ga2O3 material. Additionally, technology computer-aided design simulation software was also used to further validate the potential mechanism of burnout. Simulation results reveal that when the reverse voltage reached 350 V, the total current density increased significantly, the electric field strength reached its maximum at the interface between NiOx and β-Ga2O3, and the lattice temperature peak exceeded the melting point of β-Ga2O3 material within the drift layer. These findings show strong consistency with experimental results. This study provides an important reference for the SEB-tolerant assessment of β-Ga2O3 HJDs.