Electron irradiation hardness of high-voltage 4H-SiC Schottky diodes in the operating temperature range

Effect of irradiation with 0.9 MeV electrons on the parameters of 4H-SiC Schottky diodes with a limiting blocking voltage $U_b$ = 600 and 1700 V was studied for the first time in the range of operating temperatures $T_i$ (23 and 175$^\circ$C). The range of fluences $\Phi$ was 1$\cdot$10$^{16}$-2$\cdot$10$^{16}$ cm$^{-2}$ for devices with $U_b$ = 600 V and 5 $\cdot$ 10$^{15}$–1.5 $\cdot$ 10$^{16}$ cm$^{-2}$ for devices with $U_b$ = 1700 V. Irradiation at room temperature increases significantly the differential resistance of the base of the diodes. Irradiation with the same doses at $T_i$ = 175$^\circ$C – i.e. at limiting operating temperature of devices, does not affect practically the parameters of current-voltage characteristics. Nevertheless, the DLTS spectra demonstrate a significant increase in the concentration of deep levels in the upper half of the band gap not only after irradiation at room temperature, but also after irradiation at $T_i$ = 175$^\circ$C.