Single transistor non-volatile electrically alterable semiconductor

Abstract

A single transistor electrically programmable and erasable memory cell has a substrate of a semiconductor material of a first-conductivity type. Within the substrate are defined source, drain, regions with a channel region therebetween. A first insulating layer is disposed over the substrate and over the source, channel and drain regions. An electrically conductive, re-crystallized floating gate is disposed over the first-insulating layer and extends over a portion of the channel region and over a portion of the drain region to maximize capacitive coupling therewith. A second insulating layer has a top wall portion over the floating gate and a side wall portion immediately adjacent to the floating gate and has a thickness which permits the Fowler-Nordheim tunneling of charges therethrough. An electrically conductive control gate has two electrically connected sections: A first section is over the first insulating layer and is immediately adjacent to the side-wall portion of the second insulating layer. The first section extends over a portion of the channel region and over the source region. A second section is disposed over the top wall portion of the second insulating layer to minimize capacitive coupling with the floating gate.