Radiation tolerance analysis of 4H-SiC PIN diode detectors for neutron irradiation

Abstract

Silicon carbide (SiC) detector shows sufficient merits for the application of radiation measurement in harsh neutron radiation fields due to the strong radiation tolerance, good environment adaptability, and excellent electrical properties. In order to meet the demand for higher precision measurements, the reliability of SiC detectors under harsh neutron irradiation environments must be characterized. In this work, electrical characteristics, α-particle response, and pulse response speed of 4H-SiC PIN diode detectors were carefully investigated under 1 MeV equivalent neutron irradiation fluence from 5 × 1012 cm−2 to 1 × 1014 cm−2. Before neutron irradiation, SiC detector showed dark current as low as 10 pA at 200 V bias, with superior charge collection efficiency of more than 98%, perfect energy resolution within 0.9%, and ultrafast response speed with a rise time and decay time of 2.1 ns and 5.9 ns, respectively. After a neutron irradiation at fluence of 1 × 1014 cm−2, noticeable changes were found in the forward IV characteristics of SiC detector, but the dark current was stable below 1 nA, with only 5.7% and 0.26% degradation in charge collection efficiency and energy resolution respectively, and the pulse response speed remained unchanged. These results demonstrate 4H-SiC PIN diode detector has superior neutron radiation tolerance, and the obtained evolution characteristics are very valuable for improving the measuring accuracy of SiC detectors in the intense neutron field.