The results of an investigation of the point defects generation, redistribution and interaction with extended defects and impurities in the Si-SiO2 system during the process of its formation by means of electron paramagnetic resonance (EPR), infra-red (IR) absorption spectroscopy, metallography, transmission electron microscopy and surface photovoltage (SPV) spectra are presented. The influence of the oxidation conditions (oxidation time, cooling rate, ambient) on the defect structure of the Si-SiO2 interface has been studied. It has been established that the vacancies type defects EPR signal intensity dependence on the oxidation time (oxide thickness) reveals one or two maximum depending on the cooling rate. In the samples with the oxide thickness in the range of the I(d) maximum an interaction between point defects and extended defects occurs. It has been shown that the interaction between point defects and extended defects in the Si-SiO2 system affects the structural and electrical properties of the interface. (C) 2003 Elsevier B.V. All rights reserved.