Communication—A Powerful Method to Improve Dielectric/GaN Interface Properties: A Dummy SiO2 Process

We report a simple and effective method for improving dielectric/GaN interface properties. In the process, a 5 nm thick SiO₂ layer was deposited onto a GaN(0001) substrate via plasma-enhanced atomic layer deposition, followed by annealing at 800 °C for 300 s under a flowing N₂ atmosphere. The SiO₂ layer was then removed using buffered HF solution, and Pt/Al₂O₃/GaN metal-oxide-semiconductor capacitors were fabricated on the substrate. Positive-bias stress tests revealed that the flat-band voltage shifts were substantially reduced for devices fabricated using this process, probably because of improved interface crystallinity. This method can also be applied to other dielectric/GaN systems.