Effect of electron irradiation with an energy of 0.9 MeV on the I–V characteristics and low-frequency noise in 4$H$-SiC pin diodes

It is established experimentally that noticeable changes in the I – V characteristics and low-frequency noise in 4$H$-SiC pin diodes irradiated by electrons with an energy of 0.9 MeV are observed after doses of $\Phi\ge$ 1.4 $\times$ 10$^{15}$ cm$^{-2}$. The currents in the forward and reverse branches of the I – V characteristics vary nonmonotonically at voltages lower than 2 V with increasing dose, which is explained by the interaction between the excited electronic subsystem and metastable defects. In this case, a steady increase in the ideality factor and the series resistance of diodes in the region of exponential growth of the I – V characteristics at voltages exceeding 2 V is observed. The reliable operation of microwave devices with low-noise 4$H$-SiC pin diodes under conditions of electron irradiation is possible up to a cumulative dose of $\Phi\le$ 10$^{15}$ cm$^{-2}$. In microwave devices, the level of low-frequency noise in which is irrelevant but the stabile regime of parameters is of importance, the dose can be increased to $\Phi\approx$ 8 $\times$ 10$^{15}$ cm$^{-2}$.