Kobzar O. Defect-impurity interaction in silicon, doped with isovalent impurities

The research is devoted to an investigation of defect-impurity interaction occurred in silicon doped with tin and carbon upon ionizing irradiation and following thermal treatments. It have been found that substitutional Sn atoms effectively interact with the interstitial carbon during annealing of the irradiated silicon and in result the "interstitial carbon + tin" centres form. It was shown experimentally, that these centres may exist in two structural configurations with various thermal stability. The efficiency of interaction of interstitial carbon with tin atom was evaluated and the energy structure of found defect was modelled. Tin atom was found to affect appreciably the diffusion process of "vacancy + oxygen" centres in silicon. Diffused upon annealing "vacancy + oxygen" centres effectively interact with Sn atoms and new centres "tin + vacancy + oxygen" are created. The annealing activation energy of the new centres was determined. It was shown, that doping of n-type silicon by tin causes the decrease of Si radiation hardness, whereas in p-type silicon the doping with tin may leads to the increase of radiation stability. The irradiation doses and shallow acceptor concentrations, at which Si:Sn is more radiation stable than Si, were determined.