| 摘要 |
PROBLEM TO BE SOLVED: To improve the cell ratio by applying different back gate biases corresponding to different voltages to a plurality of insulating gate field-effect transistors and thus generating differences in driving capability of the insulating gate field-effect transistors. SOLUTION: In the operation of a flip-flop circuit of a memory cell, a silicon substrate 1 and an epitaxial layer 2 are biased to a Vcc potential. In addition, a P<+> diffusion layer 3 is biased to a GND potential. Therefore, in a driving MOS transistor including an SO1 channel region 5, a gate insulating film 6, a gate electrode 7 and SOIN<+> regions 9, 10, formed via an insulator layer 4 on the epitaxial layer 2, a back gate bias effect of the transistor is generated and the threshold value is shifted toward a negative value. This amount of shift of the threshold value generates the difference in driving capability between the MOS transistor and a transfer MOS transistor, thereby increasing the cell ratio. |
