Patent ID: 8698219
Filing Date: 2014-04-15
Classification: H01L

Abstract:
1. A semiconductor device comprising: a first transistor comprising a first semiconductor; a second transistor comprising an oxide semiconductor; a capacitor; and a node where one of a source electrode and a drain electrode of the second transistor is connected to a gate electrode of the first transistor and one electrode of the capacitor, wherein data is written by applying a first potential to the other of the source electrode and the drain electrode of the second transistor when the second transistor are turned on by applying a second potential to a gate electrode of the second transistor, wherein data is hold at the node when the second transistor is turned off, wherein data hold at the node is read out by determining whether the first transistor is in an on state or an off state when a third potential is applied to the other electrode of the capacitor, and wherein a difference between a first threshold voltage of the first transistor in the on state and a second threshold of the first transistor in the off state is kept within 2% or less before and after 1×10