Semiconductor device

摘要

It is an object to give excellent data retention characteristics to a semiconductor device in which stored data is judged in accordance with the potential of a gate of a specified transistor, by achieving both reduction in variation of the threshold voltage of the transistor and data retention for a long time. Charge is held (data is stored) in a node electrically connected only to a source or a drain of a transistor whose channel region is formed using an oxide semiconductor. There may be a plurality of transistors whose sources or drains are electrically connected to the node. The oxide semiconductor has a wider band gap and a lower intrinsic carrier density than silicon. By using such an oxide semiconductor for the channel region of the transistor, the transistor with an extremely low off-state current (leakage current) can be realized.

主权项

1. A semiconductor device comprising:
a first transistor including a gate electrically connected to a first signal line; a second transistor including a gate electrically connected to a second signal line different from the first signal line, and including a source and a drain, one of which is electrically connected to one of a source and a drain of the first transistor; a third transistor including a gate electrically connected to the other of the source and the drain of the second transistor; and a capacitor including a first electrode and a second electrode, the first electrode being electrically connected to one of the source and the drain of the first transistor and one of the source and the drain of the second transistor, and the second electrode being electrically connected to a fixed potential line, wherein each of a channel region in the first transistor and a channel region in the second transistor comprises an oxide semiconductor.