Patent ID: 7723773

Claim:
A nonvolatile semiconductor storage device comprising: a substrate having an insulating surface; a storage element included in a memory portion comprising: a first semiconductor film over the substrate, having a pair of first impurity regions formed apart from each other and a first channel formation region provided between the pair of first impurity regions; a first insulating film provided over the first channel formation region; a charge accumulating layer provided over the first insulating film; a second insulating film provided over the charge accumulating layer; and a first gate electrode layer provided over the second insulating film; an element included in a logic portion comprising: a second semiconductor film over the substrate, having a pair of second impurity regions formed apart from each other and a second channel formation region provided between the pair of second impurity regions; a third insulating film provided over the second channel forming region; and a second gate electrode layer provided over the third insulating film, wherein a first energy barrier is formed by the first insulating film against a charge of the first semiconductor film, wherein a second energy barrier is formed by the first insulating film against a charge of the charge accumulating layer, wherein the second energy barrier is higher than the first energy barrier, wherein the first insulating film and the third insulating film are different material, and wherein the first gate electrode layer and the second gate electrode layer are the same material.