Patent ID: 7728378

Claim:
A nonvolatile semiconductor memory device comprising: a memory cell having second conductive type of first impurity diffusion area and second impurity diffusion area formed on a first conductive type of semiconductor substrate, the memory cell having between the first and second impurity diffusion areas a first laminate section formed by laminating a first insulating film, a charge storage layer, a second insulating film and a first gate electrode in this order from the bottom, and a second laminate section formed by laminating a third insulating film and a second gate electrode in this order from the bottom, wherein a third impurity diffusion area sandwiched between the first laminate section and the second laminate section has the second conductive type of impurity density, the impurity density being lower than that of the first and second impurity diffusion areas and not higher than 5×10 12 ions/cm 2 .