Interface traps creation by sub-band gap irradiation in silicon dioxide on silicon without applied electric field

The effective recombination lifetime of thermally oxidized silicon wafers is found to vary little following 4.2 eV ultraviolet irradiation but decrease dramatically when the photon energy is elevated up to 4.9 eV, indicating generation of the interface traps. This finding is discussed with the model of the hot-electrons induced hydrogen redistribution in which about 2 eV energy is necessary for the electrons in the oxide conduction band to liberate a trapped hydrogen atom and generate in turn interface traps. It is stressed, however, that if the model is true the release of hydrogen atoms trapped inside the oxide should be, at least partly, responsible for the generation of interface traps because the samples used in this article are gate-free.