Study of radiation defect clusters, their structure and properties in, proton-irradiated silicon

The production of radiation defects in float-zone and pulled n-Si (rho = 1 to 500 Ωcm) irradiated by protons with energy 16, 30, 660, and 8600 MeV at T <= 320 K is studied. The changes in the initial rates of charge-carrier concentration and Hall mobility decrease under irradiation as a function of residual (technological) and doping impurity content are analysed. It is concluded that the impurity content has weak influence on radiation defect production processes under this irradiation. It is due to the fact that irradiation-induced defects are localized preferentially in clusters which consist of the core and the impurity-defect shell. Defect clustering leads to a shift of the ionization temperature range. This effect is used for estimating the size of the cluster core and the impurity-defect shell. It is shown that the sizes of the shell are, for the most part, dependent on the concentration of impurities contained in the crystal, while the core sizes are determined by the proton energy. (author)