Current–voltage characteristics of high-voltage 4$H$-SiC $p^{+}$–$n_{0}$–$n^{+}$ diodes in the avalanche breakdown mode

$p^{+}$–$n_{0}$–$n^{+}$ 4$H$-SiC diodes with homogeneous avalanche breakdown at 1860 V are fabricated. The pulse current–voltage characteristics are measured in the avalanche-breakdown mode up to a current density of 4000 A/cm$^2$. It is shown that the avalanche-breakdown voltage increases with increasing temperature. The following diode parameters are determined: the avalanche resistance (8.6 $\times$ 10$^{-2}$ $\Omega$ cm$^2$), the electron drift velocity in the $n_0$ base at electric fields higher than 10$^6$ V/cm (7.8 $\times$ 10$^6$ cm/s), and the relative temperature coefficient of the breakdown voltage (2.1 $\times$ 10$^{-4}$ K$^{-1}$).