Patent ID: 7531868

Claim:
A non-volatile semiconductor memory device comprising: a first diffused region and a second diffused region of a second conductivity type which are disposed apart from each other near a surface of a semiconductor substrate of a first conductivity type; a multilayer film including a charge storage layer, the multilayer film being composed of a plurality of insulating films vertically stacked on a channel region between the first diffused region and the second diffused region of the semiconductor substrate; and a gate electrode provided on top of the multilayer film, wherein at least one third diffused region of the first conductivity type which is in contact with only one of the first diffused region and the second diffused region and is higher in impurity concentration than the semiconductor substrate is provided in part of the channel region, and wherein, in an insulating film on an uppermost layer out of the plural insulating films composing the multilayer film, only a portion overlapping with the third diffused region in a plane view is smaller in thickness than a portion not overlapping with the third diffused region in the plane view.