Abstract:
A comprehensive mathematical modeling of the processes of radiation defect formation under 4H-SiC irradiation with Ar ions was performed. Ultraviolet photodetectors based on Cr/4H-SiC Schottky barriers with a charge carrier concentration of 3 $\cdot$ 10$^{15}$ cm$^{-3}$ in a 5 $\mu$m thick CVD layer were irradiated 7 times with Ar ions with a fluence of 1 $\cdot$ 10$^{10}$ cm$^{-2}$ (total fluence – 7 $\cdot$ 10$^{10}$ cm$^{-2}$) with an energy of 53 MeV. Based on the results of measuring the external quantum efficiency of the photodetectors at different fluences of irradiation with Ar ions and modeling the irradiation processes in SRIM/TRIM, it is shown in what range of values the concentration of radiation defects should be under irradiation for a noticeable decrease in the quantum efficiency to occur up to its complete degradation at limiting fluences. For the specified concentration of charge carriers, the limiting fluence of Ar ions leading to complete degradation of Cr/4H-SiC photodetectors was determined experimentally for the first time. As a result of modeling, the ratio of silicon and carbon vacancies by the depth of the Ar ion stopping distance was determined for the first time.
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