Heavy Ion Irradiation-Induced Electrical Degradation and Leakage Mechanism in Quasi-Vertical GaN PiN Diodes

This work investigates the electrical performance degradation and associated leakage mechanisms of quasi-vertical GaN PiN diodes subjected to high-energy tantalum (Ta) ion irradiation. Notable degradation in forward I-V characteristics is observed post-irradiation, particularly under high reverse bias, suggesting a compromised conductivity modulation capability in the bipolar structure. By performing temperature-dependent leakage mechanism evaluation, Poole-Frenkel emission (PFE), variable range hopping (VRH) and space-charge-limited current (SCLC) leakage mechanisms are revealed, respectively. Based on the PFE model fitting, the energy level of the electron trap <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\varphi_{\mathrm{t}})$</tex> is evaluated at room temperature. These findings provide essential insights for the irradiation characteristics of quasi-vertical GaN PiN diodes.