Abstract: A semiconductor memory device includes a semiconductor layer extending in a first direction, a conductive layer opposed to the semiconductor layer in a second direction intersecting with the first direction, an electric charge accumulating layer disposed between the semiconductor layer and the conductive layer, a first insulating layer disposed between the semiconductor layer and the electric charge accumulating layer, and a second insulating layer disposed between the conductive layer and the electric charge accumulating layer. The semiconductor layer includes at least one protrusion protruding in the second direction toward the electric charge accumulating layer. A position in the first direction of the protrusion is inside with respect to corner portions at both ends in the first direction of a surface opposed to the semiconductor layer in the electric charge accumulating layer.

Abstract: A semiconductor device that is suitable for high integration is provided. A first layer provided with a first transistor including an oxide semiconductor, over a substrate; a second layer over the first layer; a third layer provided with a second transistor including an oxide semiconductor, over the second layer; a fourth layer between the first layer and the second layer; and a fifth layer between the second layer and the third layer are included. The total internal stress of the first layer and the total internal stress of the third layer act in a first direction, the total internal stress of the second layer acts in the direction opposite to the first direction, and the fourth layer and the fifth layer each include a film having a barrier property.

Abstract: A transistor model that achieves precise approximation of transistor electrical characteristics is provided. The transistor model is a field-effect transistor model. A first capacitor is provided between a gate and a source. A second capacitor is provided between the gate and a drain. Each of the first capacitor and the second capacitor is a non-linear capacitor whose capacitance value is determined depending on a gate voltage. The first capacitor may be composed of a plurality of variable capacitors. The second capacitor may be composed of a plurality of variable capacitors. When CV characteristics of the first capacitor and CV characteristics of the second capacitor are adjusted, more precise simulation data is obtained.