Effect of the Electron-Irradiation Temperature on the Formation of Radiation Defects in Silicon Carbide

The effect of the electron-irradiation temperature on radiation-defect formation in silicon carbide is studied for the first time. Commercial high-voltage 4H-SiC Schottky diodes are studied. Irradiation is carried out by electrons with an energy of 0.9 MeV at temperatures of 20°C and 200°C. The spectra of radiation-induced defects are measured using nonstationary capacitance spectroscopy. It is established that with an increase in the temperature of irradiated silicon carbide, not only the number of introduced radiation defects decreases, but also their spectrum changes. If cold irradiation leads to the formation of six deep traps, then hot irradiation leads to the formation of only three traps: Z1/Z2 (0.68 eV), EH5 (1.08 eV), and EH6/EH7 (1.58 eV). During hot irradiation the number of induced radiation defects also sharply decreases, which leads to a decrease in the rate of removal of charge carriers (compensation of semiconductor conductivity) by almost four times: from 0.25 to 0.065 cm–1. It is noted that nonlinear effects in radiation-defect formation are observed in silicon carbide. At a fixed dose of irradiation of silicon carbide by electrons, the number of introduced radiation defects depends on the electron-flux density (dose-accumulation time).