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Journal of Physical Studies 21(1/2), Article 1602 [7 pages] (2017)
DOI: https://doi.org/10.30970/jps.21.1602 CARRIER CONCENTRATION IN SILICON AT RECHARGE OF THE DIVACANCY DURING THE CONFIGURATIONAL RECONSTRUCTIONG. P. Gaidar, O. P. Dolgolenko
Institute for Nuclear Research, National Academy of Sciences of Ukraine, |
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In this paper the high-resistance samples of \mbox{\textit{p}-Si} ($p_0=6.4\cdot10^{12}$ см$^{-3}$) and \mbox{\textit{n}-Si} ($n_0=2.1\cdot 10^{12}$ см$^{-3}$), grown by the floating zone melting method and irradiated with different fluences of fast neutrons at 320 K, were investigated. The irradiation was carried out by fluences of ($3.85\thinspace\cdot 10^{12}\div 3\cdot10^{13}$) n$^{\textnormal{o}}$cm$^{-2}$ in a horizontal channel of the water-cooled nuclear reactor WWR-M of the Institute for Nuclear Research of National Academy of Sciences of Ukraine. The flux of fast neutrons was defined by the $^{32}$S threshold detector (the threshold energy is equal to $E=0.95$ MeV) with an accuracy of 10 \%. Conductivity and Hall coefficient measurements were carried out by the Van der Pauw compensation method on samples of the $10\times 10\times1$ mm size with the accuracy of 3 \%. The contacts were created by rubbing aluminium into the polished silicon surface. \par In silicon, doped with donors or acceptors, the temperature dependence of electron concentration was described. This temperature dependence is associated with the recharging of divacancy at the configurational reconstruction from one configuration with a greater distortion in another configuration with a smaller distortion, and vice versa. It was found that during the configurational reconstruction of divacancy the appearance of the generalized levels of divacancy was observed: $E_c-0.23$ eV (V$^{2-}_2$) in \mbox{\textit{n}-Si} and $E_{\textnormal{v}}+0.283$ eV (V$^{+}_2$) in \mbox{\textit{p}-Si}. \par It is shown that the concentrations of the V$^{2-}_2$ and V$^{+}_2$ divacancies with the respective generalized levels are determined not only by the type of nuclear radiation, but also depend on the introduction of the point defects of the interstitial type, which create an additional deformation of the silicon lattice. The additional deformation of lattice leads to a decrease of probability of the configurational reconstruction of divacancies and, consequently, to a decrease in the concentrations of generalized levels of the double-negatively and positively charged divacancies.
PACS number(s): 61.82.Fk