Interaction between iron and point defects in silicon

By the EPR method the dose dependence of the interstitial iron concentration (NFe) in silicon is studied after 4 MeV electron irradiation in the temperature range 80 to 300 K. It is obtained that electron irradiation at temperatures lower than 280 K decreases NFe and leads to a constant value NFec. This value NFec depends on carbon concentration and does not depend on oxygen contamination in the crystals. Analysis of the possible reactions between Frenkel pair components and impurity atoms shows that iron atoms are effective centers of indirect annihilation of vacancies and interstitials in silicon. (orig.)