PACS: 61.72.Ji; 61.80.Hg; 71.55.Cn; 72.20.Jv; S5.11
Influence of growing and doping methods on radiation
hardness of n-Si irradiated by fast-pile neutrons
Abstract. Silicon n-type samples with resistivity ~2.5*103 Ohm*cm grown by the method of a
floating-zone in vacuum (FZ), in argon tmosphere (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 Gossick's 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.
Keywords: silicon, neutron irradiation, radiation hardness, radiation defects, clusters.
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