Abstract
Radiation-induced hole trapping in nitrided oxides and reoxidized nitrided oxides was investigated. Midgap voltage shift in reoxidized nitrided oxide capacitors was observed to saturate rapidly with dose, while the voltage shift in nitrided oxide capacitors continues to increase. Reoxidized nitrided oxide capacitors exhibited the unusual characteristic of greater voltage shifts when irradiated under negative bias. It is proposed that a high density of small cross-section traps exists in the nitrided oxide, while the traps in reoxidized samples are larger in cross section and concentrated in the upper half of the dielectric. An etch-off experiment demonstrated that the majority of these traps lie within ∼7 nm of the gate.