Methods of manufacturing nor-type nonvolatile memory devices including impurity expansion regions

Abstract

Methods of manufacturing NOR-type flash memory device include forming a tunnel oxide layer on a substrate, forming a first conductive layer on the tunnel oxide layer, forming first mask patterns parallel to one another on the first conductive layer in a y direction of the substrate, and selectively removing the first conductive layer and the tunnel oxide layer using the first mask patterns as an etch mask. Thus, first conductive patterns and tunnel oxide patterns are formed, and first trenches are formed to expose the surface of the substrate between the first conductive patterns and the tunnel oxide patterns. A photoresist pattern is formed to open at least one of the first trenches, and impurity ions are implanted using the photoresist pattern as a first ion implantation mask to form an impurity region extending in a y direction of the substrate. The photoresist pattern is removed. The substrate is annealed to diffuse the impurity region, thereby forming an impurity expansion region further expanding in an x direction of the substrate. The substrate is selectively removed using the first mask patterns as an etch mask to form second trenches corresponding to the first trenches. Isolation layers are formed to define active regions in the second trenches.