Nonvolatile memory devices having control electrodes configured to inhibit parasitic coupling capacitance
Non-volatile memory devices include a substrate with first and second semiconductor active regions therein. These active regions are separated from each other by a trench isolation region, which has a recess therein that extends along its length. First and second floating gate electrodes are provided. These first and second floating gate electrodes extend on the first and second semiconductor active regions, respectively. A control electrode is provided that extends between the first and second floating gate electrodes and into the recess in the trench isolation region. The recess in the trench isolation region is sufficiently deep so that the control electrode, which extends into the recess, operates to reduce (e.g., block) a parasitic coupling capacitance between the first and second floating gate electrodes.
1. A non-volatile memory device, comprising:
a substrate having first and second semiconductor active regions therein that are separated from each other by a trench isolation region within a trench, said trench isolation region having a recess therein that extends along its length and comprising a lower insulating pattern of a first electrically insulating material, and an upper insulating pattern of a second electrically insulating material that is different than the first electrically insulating material, on the lower insulating pattern;
first and second floating gate electrodes extending on the first and second semiconductor active regions, respectively, each of said first and second floating gate electrodes comprising a lower conductive pattern and a upper conductive pattern on the lower conductive pattern;
a control electrode that extends between said first and second floating gate electrodes and into the recess in said trench isolation region; and
an inter-gate insulating layer extends between said control electrode, and said first and second floating gate electrodes,
wherein a width of the lower conductive pattern of said first floating gate electrode is greater than a width of the upper conductive pattern of said first floating gate electrode,
wherein top surfaces of the lower conductive pattern disposed at both sides of the upper conductive pattern are in contact with the inter-gate insulating layer.
2. The non-volatile memory device of claim 1 , wherein a sidewall of the lower conductive pattern directly connected to one edge of the top surface of the lower conductive pattern is in contact with said trench isolation region.