7 kV Low Leakage Vertical PtOx/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.