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 ve ry thin gate oxide films have been studied, after constant current stress. Furthermore charge build up in the oxide bulk and in the anodic/cathodic ox ide regions has been investigated. For oxides thicker than 5 nm it was poss ible to provide a physical interpretation of the experimental results, show ing 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oxides, it has been shown that the degradation mechanisms can b e very different and the proposed interpretation is no longer valid. (C) 19 98 Elsevier Science Ltd. All rights reserved.