Method for fabricating nonvolatile semiconductor memory device

Abstract

A method for fabricating a nonvolatile semiconductor memory device having a stacked gate portion, including a tunnel insulating film, a floating gate electrode, a capacitive insulating film and a control gate electrode, formed over a p-type Si substrate. In the p-type Si substrate, n.sup.++ source/drain layers and n.sup.+ source/drain layers, each layer containing arsenic, are formed. In the drain region, an n.sup.- drain layer, containing phosphorus and overlapping with an entire edge of the stacked gate portion in the gate width direction, and a p layer surrounding the bottoms of the n.sup.+ and the n.sup.- drain layers are provided. In such a structure, an electric field applied between the floating gate electrode and the drain is weakened and the drain-disturb characteristics are improved during writing.