On the influence of interfaces and localised stress fields on irradiation-induced point-defect distributions in silicon

High-flux 1-MeV electron irradiation in a high voltage transmission electron microscope is used to study the influence of interfaces and localised stress fields on {113}-defect generation in silicon. A semi-quantitative model is presented to explain the observations, suggesting that the silicon oxide/silicon interface is a stronger sink for self-interstitials than for vacancies. It is shown that the position and the height of the maximum of the {113}-defect density strongly depends on the strength of the interface as a vacancy sink and that compressive straining of the silicon substrate slows down the diffusion of vacancies towards the interface.