Nand-type flash memory devices including selection transistors with an anti-punchthrough impurity region and methods of fabricating the same

Abstract

A NAND-type flash memory device including selection transistors is provided. The device includes first and second impurity regions formed in a semiconductor substrate, and first and second selection gate patterns disposed on the semiconductor substrate between the first and second impurity regions. The first and second selection gate patterns are disposed adjacent to the first and second impurity regions, respectively. A plurality of cell gate patterns are disposed between the first and second selection gate patterns. A first anti-punchthrough impurity region that surrounds the first impurity region is provided in the semiconductor substrate. The first anti-punchthrough impurity region overlaps with a first edge of the first selection gate pattern adjacent to the first impurity region. A second anti-punchthrough impurity region that surrounds the second impurity region is provided in the semiconductor substrate. The second anti-punchthrough impurity region overlaps with a first edge of the second selection gate pattern adjacent to the second impurity region.