Influence of γ-irradiation (60Со) on the concentration and mobility of carriers in Ge and Si single crystals of n-type

Abstract

Abstract. The influence of γ-irradiation ( 60 Co) (within the dose range 1×10 6 ≤ D ≤ 8×10 7 R) on the concentration and mobility of major carriers in germanium and silicon has been investigated. In the oxygen-containing samples of As Ge − n and P Si − n , and in the compensated crystals of Si − n , the mobility is shown to grow anomalously with the irradiation dose in the region of combined scattering of carriers. Proposed in this paper is the model based on accounting partial neutralization of charge of scattering centers by charge of radiation defects produced mainly around the scattering centers. This model qualitatively explains the experimental data.

Influence of gamma irradiation (60Co) on the electrophysical parameters of n-Ge with a different doping level and with oxygen impurity in different states

“…It is known [25] that in n-Ge doped with a shallow donor impurity (such as antimony or phosphorus), the Hall mobility of charge carriers, as well as the Hall coefficient, are isotropic in weak magnetic fields and anisotropic in intermediate magnetic fields. However, when germanium is doped with donors of another nature (for example, by oxygen complexes that arise during the thermal treatment process of crystals [26]), a number of peculiarities appear that depend not only on the oxygen concentration, but also on the state of this impurity in the volume of the crystal, as was shown in [27,28]. Thus, with the help of Hall measurements, an anomalous increase in the charge carrier mobility from irradiation dose in the mixed-scattering region was observed in [27] when irradiating the oxygen-containing n-germanium and n-silicon crystals.…”

“…However, when germanium is doped with donors of another nature (for example, by oxygen complexes that arise during the thermal treatment process of crystals [26]), a number of peculiarities appear that depend not only on the oxygen concentration, but also on the state of this impurity in the volume of the crystal, as was shown in [27,28]. Thus, with the help of Hall measurements, an anomalous increase in the charge carrier mobility from irradiation dose in the mixed-scattering region was observed in [27] when irradiating the oxygen-containing n-germanium and n-silicon crystals. Meanwhile the crystals, grown by the floatingzone method, which had a low content of background oxygen impurity, did not exhibit the radiation-induced increase in mobility.…”

“…Meanwhile the crystals, grown by the floatingzone method, which had a low content of background oxygen impurity, did not exhibit the radiation-induced increase in mobility. The influence of irradiation on samples with the approximately equal dopant concentration was investigated in [27].…”