A nonvolatile storage element of a single-layer gate type structure is arranged so that a floating gate is formed of a conductive layer which partly overlaps with a control gate, formed of a diffused layer, and is provided with a barrier layer covering a part of or the whole surface of the floating gate....http://www.google.es/patents/US7002830?utm_source=gb-gplus-sharePatente US7002830 - Semiconductor integrated circuit device
