EFFECTS OF NEUTRON IRRADIATION IN P-TYPE SILICON

Radiation damages in silicon single crystals irradiated by pile neutrons were investigated by using Hall effect and the carrier lifetime measurements. In p-type silicon donor-like centers were found to be introduced, the energy level of which located at about Ev+0.3eV. Its introduction rate did not depend on the kind of impurities, carrier concentrations and crystal growth methods. At the small irradiation dose level the minority carrier lifetime was controlled by the recombination through the defect centers. With the increase of dose the trapping effect became remarkable even at room temperature in conjunction with the recombination effect. At 2.6×1012nvt irradiation dose the trapping level at Ec—0.16 eV was found to be predominantly introduced. The annealing studies of 2.6×1012nvt irradiated type silicon indicated that trap centers annealed at around 200°C, subsequently recombination centers annealed at 430~480°C. Recombination centers annealed over the broad temperature range and did not show any sensitivity to the existence of oxygen impurities. The results were tentatively interpreted on the basis of the model proposed by Gossick. © 1969, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.