| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device with a new structure which can retain stored contents even when it is not supplied with power and has no limitations on the number of writes thereto, as well as heighten integration of the semiconductor device with a new structure to increase its storage capacity per unit area.SOLUTION: The semiconductor device is fabricated by using a material capable of sufficiently reducing the off-state current of a transistor, such as an oxide semiconductor material which is a wide-gap semiconductor, for example. Use of a semiconductor material capable of sufficiently reducing the off-state current of a transistor makes it possible to retain information over a long period of time. Furthermore, transistors 162 made from an oxide semiconductor constituting memory cells 190 of the semiconductor device are connected in series. This arrangement allows the source or the drain electrodes of the transistors made from an oxide semiconductor to be connected to each other in adjacent memory cells, making it possible to reduce the occupied area of the memory cells. |
