Enhanced Leakage Current and On-Resistance of β Gallium Oxide Schottky Barrier Diodes Using Effective Surface Modification

Beta-gallium oxide (β-Ga 2 O 3 ) has gained attention as a promising candidate for power device applications. Despite advances in crystal quality and device design, challenges remain, particularly in improving cleaning processes to minimize surface contamination. Common methods, such as CF 4 and O 2 plasma treatments, are widely used but often introduce surface traps, leading to higher recombination rates, reduced forward current, and increased on-resistance ( R on ). Chemical cleaning, using HCl, BOE, or HF, can also cause contamination or damage to the surface with prolonged exposure. In this work, we propose an innovative cleaning approach for β-Ga 2 O 3 substrates using short acid exposures, including HCl, BOE, and H 2 O 2, either individually or sequentially. The sequential process, starting with HCl or BOE followed by H 2 O 2, effectively removes different types of surface contaminants. To evaluate the effectiveness, Schottky barrier diodes (SBDs) were fabricated, achieving 50 times higher forward current and 31.5% lower on-resistance compared with conventional devices. Furthermore, these cleaned SBDs showed 100 times lower reverse leakage current and significantly higher breakdown voltage (∼700 V) than uncleaned devices. This innovative cleaning method holds promise for enhancing the performance of Ga 2 O 3 -based power devices.