Nonvolatile semiconductor memory device and method for manufacturing the same

Abstract

A split gate type nonvolatile semiconductor memory device having a FinFET structure includes a semiconductor substrate, parallel trenches on a surface of the semiconductor substrate, and select and memory gate electrodes perpendicular to the trenches. While either the select or the memory gate electrodes are formed prior to the other gate electrodes, each remaining gate electrode is formed adjacent to a side wall of each of the gate electrodes. The semiconductor memory device includes source/drain regions each formed between each pair of the select gate electrodes and between each pair of the memory gate electrodes in protruding portions between each pair of the trenches. A difference between heights of the select gate electrodes and the memory gate electrodes is equal to or greater than a difference between heights of insulation layers formed on the bottom of each of the trenches and the source/drain regions.