SEMICONDUCTOR DEVICE AND METHOD FOR DRIVING THE SAME

摘要

PURPOSE: A semiconductor device and a method for driving the same are provided to lower a refresh frequency by allowing information to be memorized by insulating an oxide semiconductor insulator. CONSTITUTION: A semiconductor layer includes a channel forming region. A third gate includes an oxide semiconductor. A third gate includes a first area(221) and a second area(222). The first area is overlapped with a first gate and the channel forming region. The second area is electrically connected with wiring.