Identification of paramagnetic spin dependent recombination centers on surface of silicon wafers

Electron paramagnetic resonance spectra of centers localized on (111), (110), and (100) oriented surface of silicon wafers were observed and studied using spin dependent microwave photoconductivity. The wafers were not subjected to high temperature oxidization, but oxidized on air at room temperature. The optimal experimental conditions for detection the surface recombination centers, having the sensitivity by order of magnitude greater in comparison with usual electron paramagnetic resonance technique, were discussed.