3 kV/2.9 $\mathrm{m}\Omega\cdot \text{cm}^{2}\beta-\text{Ga}_{2}\mathrm{O}_{3}$ Vertical p-n Heterojunction Diodes with Helium-Implanted Edge Termination and Oxygen Post Annealing

In this study, the high stable $\text{vertical}\text{NiO}/\beta-\text{Ga}_{2}\mathrm{O}_{3}$ p-n heterojunction diodes (HJDs) with a high breakdown voltage (VBR) of 3000 V and Baliga's figure of merit (FOM) of 3.10 GW/cm² were reported. We introduced an efficient and low-damage edge termination (ET) formed by the implantation of lightweight Helium atoms to inhibit the high electric field at the p-n junction of HJDs, increasing VBR of $\text{Ga}_{2} \mathrm{O}_{3}$ HJDs from 1330 V to 3000 V. The reverse leakage mechanisms were fitted and analyzed, revealing distinct breakdown mechanisms in He-implanted devices. Furthermore, the suitable 02 ambient post annealing (OP A) was applied, effectively reducing on-resistance $(R_{\text{on},\text{sp}})$ of $\text{Ga}2\mathrm{O}_{3}$ HJDs from 5.08 to 2.90 $\mathrm{m}\Omega\cdot \text{cm}^{2}$ and improving the performance and stability of devices. Additionally the excellent stability was characterized, including efficient charge transfer of heterojunction via density functional theory (DFT) calculation, stable forward current mechanism under 298 $\mathbf{K}\sim$ 423 K and reliable turn-on voltage $(V_{\text{on}})$ and $R_{\text{on},\text{sp}}$ under $10^{6}$ times on-off test. This work may provide a new insight into the design and fabrication of $\beta-\text{Ga}_{2}\mathrm{O}_{3}$ bipolar power devices with high-power density, power saving and long lifetime.