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

In this study, we fabricated superb $\beta $ -Ga2O3 Schottky barrier diodes (SBDs) with high breakdown voltage ( ${V}_{\text {br}}{)}$ and low leakage through combining platinum oxide (PtO $_{\text {x}}{)}$ and anodic self-aligned mesa termination (SAMT). The PtOx that forms a high barrier with $\beta $ -Ga2O3 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 ( ${D}_{\text {ee}}{)}$ were systematically studied, including 0, 0.3, 0.6, 0.9, and $1.2~\mu \text{m}$ . The results showed that the ${V}_{\text {br}}$ of the PtOx/ $\beta $ -Ga2O3 SBD increased from 1120 V to 2738 V, yielding a high power figure of merit (PFOM) of 1.02 GW/cm2. Meanwhile, the device maintained a less than $10~\mu \text{A}$ /cm2 leakage current density until -2000 V. Devices with radii of 200, 100, and $50~\mu \text{m}$ obtained highest ${V}_{\text {br}}$ of 2508, 2772, and 2738 V at a ${D}_{\text {ee}}$ of $1.2~\mu \text{m}$ , respectively. The devices can be passivated by SU-8 without ${V}_{\text {br}}$ degradation. This work provides an effective method for further improving the performance of $\beta $ -Ga2O3 SBDs and promotes the application of $\beta $ -Ga2O3 power diodes.