【Device Papers】Defect engineering in NiO/β-Ga₂O₃ p-n heterojunction diodes via post-deposition annealing for power electronics

      Researchers from Kwangwoon University have published a dissertation titled " Defect engineering in NiO/β-Ga₂O₃ p-n heterojunction diodes via post-deposition annealing for power electronics " in Materials Science in Semiconductor Processing.

Abstract

      This work presents a comprehensive study on how post-deposition annealing (PDA) influences the defect-related electrical behavior of vertical NiO/β-Ga₂O₃ heterojunction diodes (HJDs). To evaluate the defect states in the β-Ga₂O₃ bulk and NiO/β-Ga₂O₃ interface, deep level transient spectroscopy (DLTS) was employed. DLTS measurements confirmed a notable suppression of electrically active traps, with the densities of E2 and E3 levels significantly reduced from 1.99 × 10¹⁴ cm⁻³ to 1.24 × 10¹³ cm⁻³, and 2.19 × 10¹³ cm⁻³ to 4.66 × 10¹² cm⁻³, respectively. Furthermore, temperature-dependent reverse I-V (I-V-T) measurements revealed that the reverse leakage current mechanism in the HJDs is governed by a combined conduction process involving both trap-assisted tunneling (TAT) and Poole-Frenkel emission (PFE). The trap energy level contributing to TAT mechanism shifted from the E3 trap prior to annealing to the E2 trap after annealing, accompanied by a pronounced suppression of the TAT component, as corroborated by DLTS. In addition, the reduced interface-state density (Nss) after annealing likely mitigates the PF contribution. These improvements in defective characteristics led to a high breakdown voltage (BV) reaching 1.4 kV in the annealed HJDs. These results highlight PDA as an effective method for defect engineering in NiO/β-Ga₂O₃ HJDs, underscoring its potential for enabling high-voltage, next-generation power electronic applications.

DOI：

https://doi.org/10.1016/j.mssp.2026.110743