Observation of Atomic-Scale Structural Changes in Al₂O₃/GaN Interfacial Layers Prepared with a Dummy-SiO₂ Process

We previously reported that a dummy-SiO 2 process improved the dielectric/GaN interface properties [Y. Irokawa et al., ECS J. Solid State Sci. Technol. 13 , 085003 (2024)]; however, the improvement mechanism has remained unclear. In this study, the atomic-scale structural changes at Al 2 O 3 /GaN interfaces prepared with the dummy-SiO 2 process are investigated through aberration-corrected scanning transmission electron microscopy with energy-dispersive X-ray spectroscopy. The results reveal that disordered GaN(O) polarity in the interfacial layer in a sample prepared by the standard process was restored to some extent after the dummy-SiO 2 process, which likely led to the improved interface electrical properties.