Nonvolatile memory fabrication methods in which a dielectric layer underlying a floating gate layer is spaced from an edge of an isolation trench and/or an edge of the floating gate layer

摘要

A first dielectric ( 120 ) and a first floating gate layer ( 130.1 ) are formed on a semiconductor substrate ( 110 ). The first dielectric, the first floating gate layer, and the substrate are etched to form isolation trenches ( 150 ). The first dielectric ( 120 ) is etched to pull the first dielectric away from the trench edges ( 150 E) and/or the edges of the first floating gate layer ( 130 E). The trench edges and/or the edges of the first floating gate layer are then oxidized. The trenches are filled with a second dielectric ( 210.2 ), which is then etched laterally adjacent to the edges of the trench and the first floating gate layer. A second floating gate layer ( 130.2 ) is formed to extend into the regions which were occupied by the second dielectric before it was etched.