SEMICONDUCTOR MEMORY DEVICE AND METHOD OF DRIVING A SEMICONDUCTOR MEMORY DEVICE

A semiconductor memory device includes a semiconductor layer; a source layer provided in the semiconductor layer; a drain layer provided in the semiconductor layer; a body region provided in the semiconductor layer between the source layer and the drain layer; a gate insulation film provided on the body region; and a gate electrode provided on the gate insulation film, wherein data are written or read out by accumulating electric charge in the body region or releasing electric charge from the body region, and wherein a difference between the potential VSR of the source layer in a data-retaining period and the potential VGR of the gate electrode in the data-retaining period is smaller than a difference between the potential VSW of the source layer in a data write period and the potential VGR.