Electron trapping and detrapping in thermally nitrided silicon dioxide

Thermal nitridation of SiO2 was carried out at 25% and 40% of NH3 for various times and temperatures. Flat-band voltage and interface-state densities were studied as a function of processing conditions. Avalanche injection was used to study electron trapping. The density of electron traps in nitrided oxides depended on the nitridation conditions in the same way as the negative flat-band voltage (positive voltage). A consistent model for negative flat-band voltage and electron traps is presented to explain the results obtained. Thermal emission of trapped electrons dominates the detrapping mechanism. Energy depths of these traps were found to be 1.3–1.6 eV.