Patent ID: 8654566

Claim:
A driving method for a semiconductor device, the semiconductor device comprises a memory cell including: a first transistor comprising a first gate electrode; and a second transistor comprising: a second channel formation region that overlaps with at least a part of one of a source and a drain of the first transistor with an insulating layer interposed therebetween; and a second gate electrode over the second channel fat nation region, wherein one of a source and a drain of the second transistor is electrically connected to the first gate electrode so that a node is formed, the driving method comprising the steps of: turning on the second transistor so that charge is supplied to the node, turning off the second transistor so that charge is held in the node, and supplying a second potential to the second gate electrode at least when a first potential is supplied to the one of the source and the drain of the first transistor in a period during which charge needs to be held in the node, wherein the second potential has opposite polarity with the first potential.