Oxidized metal Schottky contact with high-κ dielectric field plate for low-loss high-power vertical β-Ga₂O₃ Schottky diodes

We report on vertical β-Ga 2 O 3 power diodes with oxidized-metal Schottky contact (PtO x ) and high permittivity (high-κ) dielectric (ZrO 2 ) field plate to improve reverse blocking at both Schottky contact surfaces and edges. The PtO x diodes showed excellent forward transport with near unity ideality factor and similar minimum specific on-resistance as Pt. Moreover, the PtO x contacts facilitated higher breakdown voltage and lower leakage current due to their higher Schottky barrier height (SBH) by more than 0.5 eV compared to that of Pt. Most importantly, the reduced off-state leakage of PtO x diodes enabled orders of magnitude less power dissipation than Pt ones for all duty cycles ≤0.5, indicating their great potential to realize low-loss and efficient, high-power β-Ga 2 O 3 switches. The ZrO 2 field-oxide further reduced edge leakage with a consistent increase in breakdown voltage. Device simulation demonstrated that the high permittivity of ZrO 2 also led to the peak electric field occurring in β-Ga 2 O 3 instead of the dielectric. These results indicate that the combined integration of oxidized-metal contacts to increase SBH and high-κ dielectric field plate to assist edge termination can be promising to enhance the performance of vertical β-Ga 2 O 3 Schottky diodes.