| 摘要 |
In a semiconductor device which conducts multilevel writing operation and a driving method thereof, a signal line for controlling on/off of a writing transistor for conducting a writing operation on a memory cell using a transistor including an oxide semiconductor layer is disposed along a bit line, and a multilevel writing operation is conducted with use of, also in a writing operation, a voltage which is applied to a capacitor at a reading operation. Because an oxide semiconductor material that is a wide gap semiconductor capable of sufficiently reducing off-state current of a transistor is used, data can be held for a long period. |
