A semiconductor structure for long-term learning includes a p-type silicon substrate or well having first and second spaced apart n-type regions formed therein. A polysilicon floating gate is separated from the surface of the silicon substrate by a layer of gate oxide. One edge of the polysilicon floating...http://www.google.de/patents/US4953928?utm_source=gb-gplus-sharePatent US4953928 - MOS device for long-term learning
