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

Abstract

The behavior of the nonequilibrium charge carrier lifetime (τ) in Czochralski‐grown (Cz) n‐Si after a low‐dose 60Co gamma or 1 MeV electron irradiation and subsequent annealing are investigated. Irradiated samples with different doping levels (free‐electron concentration n0 ≈ 1014−1016 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 (V2O) complexes. The Shockley–Read–Hall (SRH) theory is used to describe the experimental data. It is determined that the V2O formation is characterized by the activation energy of 1.24 ± 0.04 eV and the frequency factor of (1 ± 0.5) × 109 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) × 1010 s−1. The values of hole capture cross‐section (σp) by the single‐ and double‐charged acceptor states of V2O are obtained as (5 ± 2) × 10−13 and (8 ± 4) × 10−12 cm2, respectively.

Carrier Lifetime in 60Co Gamma and 1 MeV Electron‐Irradiated Tin‐Doped n‐Type Czochralski Silicon: Conditions for Improving Radiation Hardness

“…The VO (acceptor level of E c ‐0.17 eV) is the dominant recombination center at room temperature in 60 Co γ‐irradiated Cz n‐Si with P doping levels 10 13 –10 17 cm −3 . [ 30–33 ] Then the total change of carrier lifetime is expressed aswhere τ VO is carrier lifetime associated with VO defect.…”

“…The values of σ p %2.5 Â 10 À13 cm 2 for VO (À/0) is obtained, which is the same as in other studies Refs. [30,32,33]. Curves 2 and 3 in Figure 3 correspond to the cumulative contribution of VO and SnV in n-Si:[Sn ¼ 3 Â 10 17 cm À3 ] (curve 2) and n-Si:[Sn ¼ 6.5 Â 10 18 cm À3 ] (curve 3) calculated by Equation ( 5)À (7).…”

“…The annealing behavior of carrier lifetime for both materials is similar after γ-irradiation and subsequent isochronal annealing. In the study by Kra'sko et al,[30] it is shown that the change of τ in 60 Co γ-irradiated Cz n-Si after annealing in the temperature range of %180-350 C is caused by the divacancy oxygen (V 2 O) defect that is more recombination active than VO. In Cz n-Si:Sn, the decrease of carrier lifetime starts at %150 C, when SnV begins to dissociate and thus increases the VO concentration [1,14,18].…”

Carrier recombination and diffusion in high-purity diamond after electron irradiation and annealing

“…Under annealing, lifetimes do not change much at 600 C o but gradually recover at higher temperatures. It has been shown that the shape of the carrier lifetime dependency versus in irradiated semiconductors can be described using the following expression [Krasko 2019, Linnros 1993, Bhoraskar 1991]:…”

“…Both V and I, however, are relatively mobile at elevated temperatures leading to the intricate formation of secondary clusters and complexes with other impurities. In Si, for example, evolution of the divacancy related defects during the post-processing annealing is still an active research topic despite the decades' long history of investigations [Brotherton 1982, Krasko 2019.…”