Stress induced degradation features of very thin gate oxides

The degradation features of very thin gate oxide after Fowler-Nordheim stress have been studied. Bulk oxide, cathodic and anodic regions have been analysed from the charge build-up point of view, as well as the stress induced generation of Si/SiO2 fast interface state density. A physical interpretation of experimental results has been proposed, involving two types of stress induced positive charge building up at interface regions. It is shown that a critical oxide thickness exists, under which the degradation mechanisms could be considerably different.