Electrical conductivity changes in silicon carbide under γ-ray irradiation

Abstract

The effect of γ-ray irradiation on the electrical conductivity change has been studied by the in-situ measurement system at temperatures from 723 to 873 K in hot pressed SiC (HP-SiC) containing 2 wt.% BeO and pressureless sintered SiC (pls-SiC) containing 1 wt.% B and C. Increase of the conductivity is observed due to γ-ray irradiation in SiC, and the conductivity has a tendency to saturate up to a dose of about 2.5×10 4 Gy at each irradiation temperature. The conductivity shows similar values in pre-irradiated HP-SiC and pls-SiC at each temperature. However, the saturated conductivity in γ-ray irradiated HP-SiC is smaller than one in irradiated pls-SiC at the same irradiation temperature. It is considered that BeO existing along grain boundaries is effective to reduce the radiation-induced conductivity (RIC). RIC in HP- and pls-SiC recovers to almost the value in the preirradiation condition by annealing at the irradiation temperature. It is considered that the carriers excited by γ-ray irradiation are captured at the sites with deep energy level.