Deep-level transient spectroscopy and Hall effect studies of NTD silicon with different initial resistivities

Radiation damage was studied by deep-level transient spectroscopy and Hall effect measurements for the neutron-transmutation-doped silicon of initially high- and low-resistivity (phosphorus-contained) materials. In the irradiated materials a total of twelve electron traps was observed. A large reduction of carrier concentration and a small reduction of carrier mobility were found in the initially low-resistivity samples (<12 Omega cm), correlated closely with the divacancy responsible for two traps (E4 and E8). For the initially high-resistivity samples, (>1000 Omega cm) results showed large reductions of carrier concentration and mobility; these reductions are closely correlated with electron traps E3, E5 and E10. It appeared that the latter three traps correspond to some energy levels within the fast-neutron-induced defect clusters. However, in the initially low-resistivity samples, the formation of these traps appeared to be controlled by initially doped phosphorus atoms. In other words, due to the difference in the annealing temperature of divacancy and defect cluster, the annealing-out temperatures of carrier concentration and mobility were lower for the initially low-resistivity samples in comparison with the initially high-resistivity samples.