Patent ID: 7180121

Claim:
A semiconductor device comprising: a substrate including a semiconductor and a trench, the trench being provided on a surface of the substrate; and an electrically rewritable semiconductor memory cell provided on the substrate, the semiconductor memory cell comprising: a charge storage layer including an upper surface, a side surface and a lower surface, an area of the lower surface being smaller than an area of the upper surface, and at least a part of the charge storage layer being provided in the trench, a first insulating layer provided between the lower surface of the charge storage layer and a bottom surface of the trench, a second insulating layer provided between a side surface of the trench and the side surface of the charge storage layer and between the side surface of the trench and a side surface of the first insulating layer, a third insulating layer provided on the charge storage layer, and a control gate electrode provided on the third insulating layer.