Lifetime Control in Irradiated and Annealed Cz n‐Si: Role of Divacancy‐Oxygen Defects

The behavior of the nonequilibrium charge carrier lifetime ( τ ) in Czochralski‐grown (Cz) n‐Si after a low‐dose 60 Co gamma or 1 MeV electron irradiation and subsequent annealing are investigated. Irradiated samples with different doping levels (free‐electron concentration n 0  ≈ 10 14 −10 16  cm −3 ) are isochronally annealed at temperatures between 20 and 380 °C. It is found that τ significantly decreases after annealing in the range ≈180–280 °C, and this effect is stronger in low‐resistivity n‐Si. It is shown that change in τ in the annealing range of 180–380 °C is caused by the divacancy‐oxygen (V 2 O) complexes. The Shockley–Read–Hall (SRH) theory is used to describe the experimental data. It is determined that the V 2 O formation is characterized by the activation energy of 1.24 ± 0.04 eV and the frequency factor of (1 ± 0.5) × 10 9  s −1 , and their annealing is characterized by the activation energy of 1.54 ± 0.09 eV and the frequency factor of (2.9 ± 0.6) × 10 10  s −1 . The values of hole capture cross‐section ( σ p ) by the single‐ and double‐charged acceptor states of V 2 O are obtained as (5 ± 2) × 10 −13 and (8 ± 4) × 10 −12  cm 2 , respectively.