Electrically erasable programmable read-only memory device and method for fabricating the same

摘要

An electrically erasable programmable read-only memory device comprises a substrate having an active region, a field isolation region for isolating the active region, and extension areas integrally extended and interconnected at portions of the active region in the neighborhood of a tunnel region to enlarge an overlap margin between the active region and tunnel region. A tunnel ion implanted region is formed in a portion of the active region including the tunnel region and a tunnel dielectric film is formed on a portion of the active region corresponding to the tunnel region. A gate dielectric film is formed on the remaining portion of the active region except for the portion corresponding to the tunnel region. A floating gate is formed in common on the tunnel region and active region and a control gate is formed on the floating gate via an insulating film. A selection gate is formed on the gate dielectric film at a predetermined distance from the control gate. A source region, a drain region and a source/drain region are self-aligned with the selection gate and floating gate and formed on the active region. The extension areas serve to prevent misalignment between the active region and tunnel region during fabrication and, furthermore, mitigate degradation in the quality of the tunnel dielectric film.