Dolgolenko A. Cluster effect of radiation defects in atomic and binary semiconductors.

The dissertation is devoted to: i) the investigation of effects which arise due to the interaction of high energy nuclear irradiation (fast-pile neutrons, electrons and protons with energy 50 MeV and 24 GeV protons) with monatomic and binary semiconductors (Si, InSb, InP, Si<Ge>, Cu2Se); ii) the study of changes of the semiconductor electrophysical properties due to the clusterization effects of radiation defects both under processes of irradiation and during thermal annealing. In the work the problem of interactions of the irradiation defects with screening centers within the space charge regions of defect clusters is solved. On the base of proposed solution the effective concentration of carriers in dependence on temperature and irradiation fluence of high energy particles was calculated for n and p Si in the frame of the corrected model of defect clusters. The new method for the increasing of radiation hardness of nuclear detectors due to the doping of n Si by donor impurities (chromium or sulfur)is proposed. The criteria of radiation hardness, thermal stability of defect clusters and separated single defects are determined. The modifications of the radiation defects due to the background impurities of oxygen and carbon are studied. It is determined the position of the energy level for interstitial silicon atoms in the forbidden gap of silicon. The high probability for the formation of clusters under irradiation by 24 GeV protons and the low value of activation energy for their annealing are explained by the clusterization of radiation defects.