Patent ID: 8339837

Claim:
A method for driving a semiconductor device, the semiconductor device comprising: a first transistor, a second transistor, and a capacitor, wherein one of source and drain of the first transistor and one of source and drain of the second transistor are electrically connected to a bit line, wherein a gate of the second transistor is electrically connected to a write word line, wherein the other of source and drain of the first transistor is electrically connected to a source line, wherein one electrode of the capacitor is electrically connected to a write-read word line, and wherein a gate of the first transistor, the other of source and drain of the second transistor, and the other electrode of the capacitor are electrically connected to each other to form a node where electric charge is held, the method comprising the steps of: supplying a potential at which the second transistor is turned on to the write word line, and supplying a ground potential to the source line in a writing period, thereby storing electric charge in the node; and supplying a ground potential to the write word line and the write-read word line, and supplying a same potential to the source line and the bit line in a holding period after the writing period, thereby holding the electric charge in the node.