US Patent 8654567 Semiconductor memory device

A semiconductor memory device includes a bit line; two or more word lines; and a memory cell including two or more sub memory cells that each include a transistor and a capacitor. One of a source and a drain of the transistor is connected to the bit line, the other of the source and the drain of the transistor is connected to the capacitor, a gate of the transistor is connected to one of the word lines, and each of the sub memory cells has a different capacitance of the capacitor.