The effect of radiation damage on carrier mobility in neutron-transmutation-doped silicon

Abstract

The effect of radiation damage on neutron-transmutation-doped silicon of initially low- and high-resistivity materials has been studied by electrical property measurements. The materials were irradiated with a moderate thermal (0.45-1.0*1018 neutrons cm-2) and fast (0.45-8.1*1016 neutrons cm-2) neutron fluences. After irradiation, a small reduction of carrier mobility of the initially low-resistivity materials was observed, while the reduction of conductivity was large. The annealing behaviour and temperature dependence of mobility of the materials indicate that the mechanism of carrier scattering is dominated by ionised impurities acting as point defects. The conductivity of those materials was recovered after annealing at 560 degrees C for 60 min. In the range of annealing temperatures below 600 degrees C, the carrier mobility of initially high-resistivity materials decreased together with the conductivity. The last result can tentatively be explained by a defect cluster model for fast-neutron-induced lattice damage.