Semiconductor Physics, Quantum Electronics & Optoelectronics. 2007. V. 10, N 1. P. 004-012.
The radiation hardness of pulled silicon doped with germanium
Institute for Nuclear Research, NAS of Ukraine,
47, prospect Nauky, 03680 Kyiv, Ukraine, fax: 380-44-5254463
* Corresponding author: e-mail: gaidar@kinr.kiev.ua
Abstract. The radiation hardness of Czochralski grown n-type silicon samples doped
with germanium (N Ge = 2×10 20 cm −3 ) and without it was investigated after irradiation by
fast neutrons. The dependence of the effective carrier concentration on fluence was
described in the framework of Gossick’s corrected model. It was found that doping the
germanium impurity resulted in increase of n-Si radiation hardness. The isothermal
annealing of n-Si 〈Ge〉 after fluence 1.4×10 14 n o ⋅cm
−2 was studied. It was shown that the
annealing of defect clusters is caused by the annihilation of vacancy type defects in
clusters with interstitial defects. For di-interstitial (Е 1 = 0.74 eV; ν 1 = 3.5×10 6 s
−1 ),
silicon interstitial atom (Е 2 = 0.91 eV; ν 2 = 7×10 6 s
−1 ) and vacancy (Е V = 0.8 eV; ν =
1×10 7 s
−1 ) the migration energies and frequency factors were determined. During the
storage at room temperature, the behaviour of defect levels E c −0.17 eV and E c −0.078 eV
was studied in the samples of Si (DOFZ) and Si 〈Ge〉, correspondingly.
Keywords: silicon, neutron irradiation, radiation hardness, radiation defects, clusters.
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