Radiation-induced damage of silicon-carbide diodes by high-energy particles

The radiation hardness of three types of commercial Schottky rectifier diodes based on silicon carbide (4$H$-SiC, base layer doping level (3–7) $\times$ 10$^{15}$ cm$^{-3}$) under electron (0.9 or 3.5 MeV electrons) and proton irradiation (15 MeV protons) is studied. The forward and reverse current–voltage characteristics of the diodes are monitored. In the initial state, the diodes have a breakdown voltage of 1–2 kV and an almost ideal forward current–voltage characteristic. It is found that the series resistance of the diodes is the most sensitive to radiation and governs the radiation hardness. This resistance grows by nearly 10 orders of magnitude and reaches a value of 10$^9\Omega$ at high doses. The threshold doses of electron irradiation fall within the range $D_{\mathrm{th}}\approx(0.5-2)\times10^{16}$ cm$^{-2}$ and depend on the electron energy and doping level of the base layer, and those of proton irradiation, $D_{\mathrm{th}}\approx5\times10^{13}$ cm$^{-2}$.