Patent ID: 8106443

Claim:
A non-volatile semiconductor device comprising: an n type well formed in a semiconductor substrate having a surface, the surface having a plurality of stripe shaped grooves formed along a first direction and a plurality of stripe shaped ribs formed along the first direction; a plurality of stripe shaped p type diffusion regions each formed in an upper part of corresponding one of the plurality of ribs, the plurality of stripe shaped p type diffusion regions being formed along the first direction; a tunneling insulation film formed on the grooves and the ribs; a charge storage film formed on the tunneling insulating film; a gate insulation film formed on the charge storage film; and a plurality of stripe shaped conductors formed on the gate insulating film, the plurality of stripe shaped conductors arranged in a direction intersecting the longitudinal direction of the ribs with a predetermined interval; wherein impurity diffusion structures at both side walls in each of the ribs are asymmetric.