A nonvolatile semiconductor memory device includes a memory cell array
region including a plurality of NAND cells, each NAND cell having a
plurality of memory cell transistors, and which are arranged in series,
and a plurality of select transistors. A trench-type isolation region is
formed between columns in the array of the NAND columns. The trench-type
isolation region is formed in self-alignment with end portions of the
channel region and a floating gate of the memory cell transistor, formed
in self-alignment with the end portion of a channel region of the select
transistor, and has a recess formed in at least the upper surface between
the floating gates of the memory cell transistors.