Charge-carrier recombination in silicon irradiated with γ-rays of different energies

Comparative experiments are made to study the nonequilibrium charge-carrier recombination in silicon irradiated with γ-rays of 50Co and of the bremsstrahlung spectrum of electrons with maximum energy 100 MeV. n- and p-Si crystals with ϱ = 10 to 1000 Ωcm grown by Czochralski and vacuum float-zone techniques are used. The temperature and injection dependences of nonequilibrium charge-carrier lifetimes measured by a phase method are analyzed. It is found that when irradiating with γ-rays of 60Co a great number of recombination centers are produced which are mainly complexes of irradiation-generated vacancies and interstitials with dopants (phosphorus, boron) and technological (oxygen, carbon) impurities. As distinct from this, the dominant recombination centres in silicon irradiated with γ-rays of the bremsstrahlung spectrum are divacancies involved in defect clusters, surrounded by the potential barrier Ψ for the majority charge carriers. The parameters of recombination centres (energy level spectrum, annealing temperatures, charge-carrier capture coefficients) in crystals studied under γ-irradiation are determined. The peculiarities in the charge-carrier recombination processes due to the localization of recombination centres in defect clusters generated by photonuclear reaction products are discussed. [Russian Text Ignored]