Model for defect generation at the (1 0 0)Si/SiO2 interface during electron injection in MOS structures

Abstract

The generation of interface defects during the injection of electrons in metal-oxide–semiconductor (MOS) structures with thin SiO2 gate layers and SiO2/ZrO2 gate stacks is investigated. A model is proposed to explain the kinetics of interface defect generation, based on the depassivation of trivalent silicon dangling bonds (Si3SiH→Si3Si) at the (100)Si/SiO2 interface by the injected electrons. A gaussian spread for the activation energy Ed related to the dissociation of the SiH bond is included in this model. Comparison with experimental results reveals that the mean value of the activation energy Edi decreases linearly with the electric field Eox across the SiO2 layer. This behaviour is attributed to the alignment of the Si–H dipole moment with respect to Eox, which favours the dissociation of the SiH bond.