Abstract: A non-volatile semiconductor memory device includes a memory cell transistor having a memory cell capable of writing and erasing data, and a peripheral circuit that drives the memory cell which includes a first p-channel MOS transistor including a gate electrode that is formed on a semiconductor layer with a first gate insulation film therebetween, a channel region that is formed on a surface of the semiconductor layer and has a first peak dopant concentration, a source region and a drain region that have a second peak dopant concentration higher than the first peak dopant concentration, and overlap regions that extend between the channel region and the source region and the drain region, and also below a portion of the gate electrode, that have a third peak dopant concentration higher than the first peak dopant concentration and lower than the second peak dopant concentration by one order of magnitude or more.

Abstract: A semiconductor device according to an embodiment includes a semiconductor substrate, and a gate dielectric film is provided on the semiconductor substrate. A first gate electrode is provided on the gate dielectric film. Lower end portions of side surfaces of the first gate electrode are inclined toward a center of a channel portion. A sidewall film covers the side surfaces of the first gate electrode. A void or a low dielectric material having a dielectric constant lower than that of the sidewall film is located between the lower end portions of the side surfaces of the first gate electrode and the sidewall film.

Abstract: A non-volatile semiconductor memory device includes a memory cell transistor having a memory cell capable of writing and erasing data, and a peripheral circuit that drives the memory cell which includes a first p-channel MOS transistor including a gate electrode that is formed on a semiconductor layer with a first gate insulation film therebetween, a channel region that is formed on a surface of the semiconductor layer and has a first peak dopant concentration, a source region and a drain region that have a second peak dopant concentration higher than the first peak dopant concentration, and overlap regions that extend between the channel region and the source region and the drain region, and also below a portion of the gate electrode, that have a third peak dopant concentration higher than the first peak dopant concentration and lower than the second peak dopant concentration by one order of magnitude or more.