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Description
The study is concerned with enhanced influence of defect clusters on the profiles of the electric field E and effective space charge concentration Neff in Si detectors irradiated with 1.62 GeV 40Ar ions and operating at temperatures from 292 down to 200 K. The electric field profiles reconstructed from the shapes of the detector current pulse response measured by TCT demonstrated the double-peak electric field distribution and space charge sign inversion on lowering the temperature, all typical of Si detectors irradiated with hadrons and neutrons. To find a correlation with microscopic parameters specific to the damage induced by ions, the profiles were simulated in terms of the model of two effective deep levels of radiation-induced defects. It is shown that the reconstructed and simulated distributions are in a qualitative agreement; however, simulation required an accurate correction of the deep acceptor parameters and the use of the density of thermally generation current much higher than the experimental value. The latter was ascribed to the generation of a significantly higher concentration of primary vacancies that form defect clusters and affect the parameters of deep acceptors and their interaction with equilibrium carriers from the detector generation current.