Radiation Defects in Thermal-Donor-Doped Silicon

The nature of radiation defects in thermal-donor-doped silicon crystals was studied by analyzing the deep level transient spectroscopy (DLTS) spectrum and carrier concentration. It is ascertained using the DLTS technique that the concentration of thermal donors decreased with annealing of A-centers. Namely, an A-center interacted with a thermal donor during annealing and both lost their electrical properties. The energy levels at Ec-0.17 eV, Ec-0.23 eV and Ec-0.43 eV were introduced in samples doped with group III atoms or group V atoms by irradiation. An Ec-0.27 eV level and Ec-0.21 eV level were generated during annealing at 240°C and 320°C, respectively. Sixty percent of the electrically active defects introduced by neutron irradiation were not annealed after 20 min at 400°C.