US Patent 7095651 Non-volatile semiconductor memory device

A memory cell has a selection transistor constituted of an MOS transistor having a gate electrode and a cell transistor constituted of an MOS transistor having the same polarity as the selection transistor, in such a configuration that these two transistors are connected in series. A bit line is connected to a drain region of the selection transistor and a word line is connected to the gate electrode thereof. A gate electrode of the cell transistor is not electrically connected anywhere so as to be in a floating potential state, while a drain region thereof is connected to a source region of the selection transistor. A source line is connected to a source region of the cell transistor.