| 摘要 |
PROBLEM TO BE SOLVED: To perform readout of information and writing of information by a method wherein the conductive gates of transistors for readout use and switch use are connected with a first wiring, second and sixth conductive regions are connected with a writing information setting line, a fourth conductive region is connected with a second wiring and the source/drain regions of a transistor for current control use are connected with a prescribed potential. SOLUTION: At the time of writing information, a transistor TR2 for switch use is made to have continuity and is stored in a channel formation region CH1 of a transistor TR1 for readout use in the form of a potential. At the time of reading information, the threshold value of the transistor TR1 is changed depending upon the potential stored in the region CH1 of the transistor TR1 . At the time of the reading information, the information storage state of the transistor TR1 can be decided on the basis of the magnitude (including 0) of a channel current by applying the properly selected potential to a conductive gate. By detecting the operating state of the transistor TR1 , information is read. Accordingly, the reading/writing of information can be reliably performed. |
