On the degradation kinetics of thin oxide layers

After Fowler-Nordheim stress, since SiO2 charge trapping occurs up to final dielectric breakdown, oxide layers degrade. The degradation features of very thin gate oxide films have been studied, after constant current stress. Furthermore charge build up in the oxide bulk and in the anodic/cathodic oxide regions has been investigated. For oxides thicker than 5 nm it was possible to provide a physical interpretation of the experimental results, showing a power law of charge trapping kinetics as a function of stress level. For thinner oxides, it has been shown that the degradation mechanisms can be very different and the proposed interpretation is no longer valid. (C) 1998 Elsevier Science Ltd. All rights reserved.