Irradiation Enhancement of Electrical Properties of Passive Impurities in Silicon Crystals

Abstract

Radiation defect formation processes in silicon crystals for the cases when concentrations of electrical non-active impurities (oxygen, carbon) prevail over main impurities determining silicon conductivity, are being covered in this paper. The role of interstitial atoms and vacancies, oxygen and impurity atoms in formation of radiation defects of A- and E-centers and divacancies, as well as their influence on electrical and optical properties of silicon crystals are shown. Energy levels of radiation defects in forbidden gap of silicon and their introduction rates were defined based on temperature dependencies of the concentrations of charge carriers at different irradiation doses. The capture probability of interstitial atoms and vacancies by main and passive impurities is taking into account. In addition to known A- and E-centers, along with disordered regions (clusters), a new radiation centers with energetic levels at Еc - 0,33eV; Еc -0,40eV and Еc -0,22eV were detected and studied. The first level is connected with silicon interstitial atoms, whereas the second corresponds to divacancies and the last one is identified as divacancy + oxygen.