INFLUENCE OF DIVACANCY-OXYGEN DEFECTS ON RECOMBINATION PROPERTIES OF n-Si SUBJECTED TO IRRADIATION AND SUBSEQUENT ANNEALING

The variation of recombination properties in n-Si grown by the Czochralski method, doped to the free electron concentration no similar to 10(14)divided by 10(16) cm(-3), irradiated with Co-60 gamma-quanta or 1-MeV electrons, and isochronously annealed for 20 min in the temperature interval 180-380 degrees C, in which divacancy-oxygen (V2O) complexes are formed and annealed, has been studied in detail. The non-equilibrium charge carrier lifetime tau is found to significantly decrease after the annealing in a temperature interval from 180 to 280 degrees C, with the effect being stronger for low-resistive n-Si. It is shown that a change in tau after the annealing at 180-380 degrees C is caused by divacancy defects, most probably V2O. By analyzing the experimental data with the help of the Shockley- Read-Hall statistics, it is found that the formation of V2O defects is characterized by an activation energy of 1.25 +/- 0.05 eV and a frequency factor of (1 +/- 0.5) x 10(9) s(-1), and their annealing by an activation energy of 1.54 +/- 0.09 eV and a frequency factor of (2.1 +/- 1.4) x 10(10) s(-1). The values of the hole capture cross-sections by singly and doubly charged acceptor states of V2O are obtained as: (5 +/- 2) x 10(-13) and (8 +/- 4) x 10(-12) cm(2), respectively.