Direct experimental evidence linking silicon dangling bond defects to oxide leakage currents

Stress induced leakage current is an important and quite possibly fundamental physically limiting problem in the scaling of metal-oxide-silicon integrated circuitry. We present evidence linking specific atomic scale defects to leakage currents in thermally grown silicon dioxide thin films on silicon. The defects identified are oxygen deficient silicon "dangling bond" centers. These centers have been identified through electron spin resonance measurements. We find a strong correspondence between the generation of an oxygen deficient silicon dangling bond defect in the oxide and the appearance of oxide leakage currents. We observe a strong correlation between the disappearance of these centers and the disappearance of leakage currents in relatively low temperature anneals (200°C) in air. We also propose a model which provides an extremely straightforward explanation for the frequently reported close correspondence between the generation of stress induced leakage current and the generation of Si-SiO₂ interface states.