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p− SiGe whisker samples with a diameter of ∼40 µm, grown by chemical precipitation from the vapor phase, have been investigated. Temperature dependences of the thermal e.m.f. and conductivity within the temperature interval 20…400 K have been measured. It has been shown that the mobility of holes in p − SiGe whiskers upon the average is 1.5 times higher than that in bulk Si − Si samples. p − SiGe whiskers possess smaller phonon scattering and larger phonon dragging in comparison with the bulk p − Si samples. [ABSTRACT FROM AUTHOR]

The A-centers (VO) annealing and transformation of precursors to form stable CiOi defects during these processes are described. It was found the necessity to take into account annihilation of vacancy type defects with the interstitial type mobile defects to describe the annealing of defects. It was shown that the energies of migration for vacancy (V) and interstitial carbon atoms Ci that are defined by the degree of their localization in silicon lattice at the temperature close to 550 K are equal Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed., and Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed., accordingly. The values for potential barriers and their positions on the migration path of interstitial carbon atoms to oxygen (Oi) in the region for capture of Ci atom by Oi atom (with the radius 14.7 Å) are determined. It was brought evidences that vibration band of absorption at 865.9 cm-1 is attributed to A - center modified by carbon, and the band is attributed to a metastable state of CiO2i defect associated with an oxygen dimer. The position of the center donor level in the forbidden band of silicon is determined as CV + 0.415 eV. [ABSTRACT FROM AUTHOR]

We have studied the high-resistance samples of p-Si (p00 = (3.3 ± 0.5) x x 1012 cm-3) and n-Si (n0 = (2.0 ± 0.3) x 1012 cm-3) grown by the floating-zone technique after the irradiation by fast-pile neutrons at 287 ?. The dose and the temperature dependences of the effective concentration of carriers have been measured. The calculation has been carried out in the framework of Gossick's corrected model. It is shown that the radiation hardness of n- and p-Si, on the one hand, is defined by clusters, and, on the other hand, by vacancy defects (acceptors) in n-Si and by interstitial defects (donors and acceptors) in p-Si. We have determined that, during the irradiation of p-Si by small doses of neutrons, the change of a charge state of interstitial defects leads to the annealing of these defects and to a decrease of their introduction rate. [ABSTRACT FROM AUTHOR]

The radiation hardness of Czochralski grown n-type silicon samples doped with germanium (NGe = 2×1020 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 after fluence 1.4×1014 no°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 (E1 = 0.74 eV; E1 = 3.5×106 s-1), silicon interstitial atom (E2 = 0.91 eV; v2 = 7×106 s-1) and vacancy (EV = 0.8 eV; v = 1×107 s-1) the migration energies and frequency factors were determined. During the storage at room temperature, the behaviour of defect levels Ec-0.17 eV and Ec-0.078 eV was studied in the samples of Si (DOFZ) and Si , correspondingly. [ABSTRACT FROM AUTHOR]

Silicon n-type samples with resistivity ∼2.5·103 Ohm·cm grown by the method of a floating-zone in vacuum (FZ), in argon atmosphere (Ar) and received by the method of transmutation doping (NTD) are investigated before and after irradiation by various doses of fastpile neutrons at room temperature. The radiation hardness of n-type silicon is shown to be determined first of all by the introduction rate of defect clusters and their parameters and then by the introduction rate of defects into the conducting n-Si matrix. The presence of oxygen, argon atoms and A-type defects (dislocation loops of the interstitial type) mainly increases the radiation hardness of n-Si. The effective concentration of carriers in irradiated silicon was calculated in the framework of Gossicks model taking into account the recharges of defects both in the conducting matrix of n-Si and in the space-charge regions of defect clusters. Grown by the method of the floating-zone melting in argon atmosphere the neutron-transmutation-doped silicon (NTD) has elevated radiation hardness. The introduction rate of divacancies in the conducting matrix of n-Si (NTD) is about five times less than in n-Si (FZ) and ∼2 times less than in n-Si (Ar). The availability of the deformation strain field surrounding the argon-type impurities as well as A-type defects is supposed to promote the annihilation of divacancies with interstitial atoms of silicon. [ABSTRACT FROM AUTHOR]