Effective surface diffusion of nickel on single crystal β-Ga₂O₃ for Schottky barrier modulation and high thermal stability

β-Ga₂O₃ Schottky barrier diodes (SBDs) were demonstrated with Ni Schottky contact deposited by the confined magnetic field-based sputtering (CMFS) method. A shallow interfacial layer was formed by the diffusion of Ni into β-Ga₂O₃ after post-annealing treatment, which significantly influenced the electrical performance of the CMFS-Ni/β-Ga₂O₃ SBDs. The CMFS method was used to vary the Schottky barrier height and the ideality factor from 0.84 to 1.33 eV and 1.20 to 1.04, respectively. The leakage current of the CMFS-SBDs was only 10% of the leakage current using E-beam Ni-based SBDs, and the thermal stability of the CMFS-SBDs also was much higher than that of the E-beam Ni SBDs. We confirmed that the effective diffusion of Ni atoms could substitute for Ga through the activation of the β-Ga₂O₃ with CMFS.