Patent ID: 8008705

Claim:
A semiconductor storage device comprising: a plurality of first-conductivity-type diffusion regions extending in parallel with one another along one direction on a surface of a well of a second conductivity type; a gate electrode extending along the one direction and being disposed on a substrate via a substrate insulating film between two mutually adjacent ones of said plurality of first-conductivity-type diffusion regions; and a word line extending along a direction perpendicular to said one direction and three-dimensionally intersecting said gate electrode, wherein an area of the well not covered by said gate electrode and said word line has a trench surrounding one of the plurality of first-conductivity-type diffusion regions within the area a trench insulating film being buried in said trench, and wherein said trench is formed between said one of the plurality of first-conductivity-type diffusion regions and said gate electrode such that said one of the plurality of first conductivity-type diffusion regions and said gate electrode respectively contact opposing surfaces of sidewalls of said trench.