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

Beta-gallium oxide (β-Ga2O3) 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 CF4 and O2 plasma treatments, are widely used but often introduce surface traps, leading to higher recombination rates, reduced forward current, and increased on-resistance (Ron). 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-Ga2O3 substrates using short acid exposures, including HCl, BOE, and H2O2, either individually or sequentially. The sequential process, starting with HCl or BOE followed by H2O2, 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 Ga2O3-based power devices.