Semiconductor memory device with cell transistors having electrically floating channel bodies to store data

Abstract

A semiconductor memory device includes: a semiconductor device base having an insulating substrate and a semiconductor layer overlying it; a cell array formed on the semiconductor device base with cell transistors disposed in such a manner that each of source and drain layers is shared by adjacent two cell transistors arranged in a direction, the cell transistor having an electrically floating channel body to store data defined by a carrier accumulation state of the channel body; and logic transistors formed on the semiconductor device base to constitute a peripheral circuit of said cell array, wherein at least a part of source and drain layers of each the cell transistor is formed with a thickness different from source and drain layers of the logic transistors.