Influence of Gamma-Ray and Neutron Irradiation on Injection Characteristics of 4H-SiC pn Structures

Abstract

The effect of gamma-ray and neutron irradiation on recombination current, injection electroluminescense and the value of the lifetime of nonequilibrium carriers for 4H-SiC pn structures was investigated. The irradiation was carried out with gamma-ray (dose 5x106 rad) and 1 MeV neutrons in the doses range from 1.2x1014 cm-2 to 6.24x1014 cm-2. Neutron irradiation with a dose 1.2x1014 cm-2 increased the recombination current, decreased the lifetime for deep-level recombination in the space charge region and decreased the intensity of the edge injection electroluminescense (hnmax » 3.16 eV) by 1.5-2 orders of magnitude; the neutron irradiation with high dose (6.24x1014 cm-2) resulted in increase of the recombination current up to 2 orders of magnitude and decrease of lifetime at least up to 2 orders of magnitude. Gamma-ray irradiation and annealing at temperatures in the range 350-650 K left the recombination current and lifetime practically unchanged.