High-voltage avalanche 4$H$-SiC diodes with a protective semi-insulating area

High-voltage 4$H$-SiC diodes with controlled avalanche breakdown at a reverse voltage of 1460 V have been fabricated. To eliminate edge effects on the periphery of the diodes, a semi-insulating area was created by irradiation with high-energy (53 MeV) argon ions. The fabricated diodes operate at avalanche current densities of $\sim$10$^3$ A/cm$^2$, and the avalanche resistance is no more than 0.03 $\Omega$ $\cdot$ cm$^2$. At a current pulse duration of 4 $\mu$s, the avalanche energy dissipated by the diodes to failure (due to secondary thermal breakdown) and local thermal overheating are 5 J/cm$^2$ and 850$^\circ$C, respectively.