Interpretation of Leakage Current in Ni/n-(Al)GaN Schottky Structures and Its Influence on Surface Preparation Conditions

Abstract Electrical properties of Ni/n-(Al)GaN Schottky structures formed on oxide-etched and oxidized surfaces are studied. The oxide-etched samples formed on MBE layers showed smaller and more scattered SBHs, indicating the influence of surface patches is much larger as compared with that for MOCVD layer. Existence of surface oxides reduces the effective SBH, which is accompanied with increase of the reverse leakage current, while post-annealing in N2 improves interface properties.