Deep level defects produced by electron irradiation and their annealings in undoped germanium

Abstract

Abstract The defect levels produced in undoped p-type germanium by irradiation with 1.5 MeV or 2.0 MeV electrons and the annealing behaviour of the levels were studied by the DLTS technique. The positions of the trap levels, their concentrations and the cross sections for hole trapping of these traps were determined and the variation of the introduction rates of the traps with the energy of irradiation is reported. The level located at E v +0.22 eV should be ascribed to a divacancy-oxygen complex and the E v +0.31 eV levels to a defect-containing oxygen with regard to the effects of electrically inactive impurities. From the results of annealing under reverse or forward biases, the defect associated with the E v +0.31 eV level is considered to be annealed by an ionization- enhanced mechanism.