| 摘要 |
PROBLEM TO BE SOLVED: To provide an SRAM having excellent characteristics. SOLUTION: A back gate electrode is provided on a board with an insulating surface, a semiconductor layer equipped with an N-type impurity region is provided on the board through the intermediary of an insulating film, covering the back gate electrode. The back gate electrodes is formed, overlapping only on either one of a source or a drain, but not on the other one and kept at 0 potential or certain negative potential. An N channel-type thin film transistor has a structure is which two gate electrodes are formed on the semiconductor layer through the intermediary of a gate insulating film, including the above back gate electrode. A P-channel thin film transistor has a structure in which a semiconductor layer with a P-type impurity region is formed on the board through the intermediary of an insulating film, and a single gate electrode is formed on the semiconductor layer through the intermediary of a gate insulating film. The N-channel and P-channel thin film transistor are combined for the formation of a complementary MOS circuit, and the MOS circuits are combined into a static RAM. |
