Decrease of Charge Collection Due to Displacement Damage by Gamma Rays in a 6H-SiC Diode

Charge collection efficiency (CCE) of 6H-SiC diodes was evaluated before and after gamma irradiation using a Co-60 source. After gamma irradiation of 96 Mrad(SiC), CCE at a bias of 150 V decreased from 95% to 70%. The degradation of diffusion length of minority carriers was evaluated from the change in the applied bias dependence of CCE due to gamma irradiation. We also discuss whether non-ionizing energy loss (NIEL) analysis can be applied to evaluate the diffusion length degradation of 6H-SiC as well as the carrier removal rate.