Patent ID: 7582530

Claim:
A method comprising: forming a plurality of floating gates over a substrate, each individual floating gate being separated by a first trench isolation structure and a second isolation trench structure, wherein each individual floating gate has a base having a lateral width that overhangs the first and second trench isolation structure, the base of each individual floating gate being a bottom surface of each individual floating gate substantially parallel to and nearest the substrate; and removing laterally inward portions of each individual floating gate to provide a plurality of modified individual floating gates, each modified individual floating gate having a pair of sidewalls that taper inwardly away from the first and second trench isolation structure such that the lateral width of the base of each modified individual floating gate is greater than the lateral width of the upper surface of each modified individual floating gate, the upper surface of each individual floating gate being that surface substantially opposite the base, wherein the base of each modified individual floating gate remains overhanging the first and second isolation trench structure, wherein the act of removing comprises thermally oxidizing the individual floating gates to form a layer of thermal oxide thereover each individual floating gate and isotropically etching the thermal oxide layer.