2.7 kV Low Leakage Vertical PtO_x/β-Ga₂O₃ Schottky Barrier Diodes With Self-Aligned Mesa Termination

In this study, we fabricated superb β-Ga ₂ O ₃ Schottky barrier diodes (SBDs) with high breakdown voltage ( V _br ) and low leakage through combining platinum oxide (PtO _x ) and anodic self-aligned mesa termination (SAMT). The PtO _x that forms a high barrier with β-Ga ₂ O ₃ enables the SAMT to function sufficiently. The in-situ annealing dry etch process repair the mesa sidewall and improve the Schottky contact well. SBDs with different mesa-etched depths ( D _ee ) were systematically studied, including 0, 0.3, 0.6, 0.9, and 1.2 μm. The results showed that the V _br of the PtO _x /β-Ga ₂ O ₃ SBD increased from 1120 V to 2738 V, yielding a high power figure of merit (PFOM) of 1.02 GW/cm ² . Meanwhile, the device maintained a less than 10 μA/cm ² leakage current density until -2000 V. Devices with radii of 200, 100, and 50 μm obtained highest V _br of 2508, 2772, and 2738 V at a D _ee of 1.2 μm, respectively. The devices can be passivated by SU-8 without V _br degradation. This work provides an effective method for further improving the performance of β-Ga ₂ O ₃ SBDs and promotes the application of β-Ga ₂ O ₃ power diodes.