| 摘要 |
A semiconductor circuit has a plurality of MISFETs formed with channel films comprised of semiconductor layers on an insulation film. Channel film thicknesses of each MISFET are different. A correlation relationship is fulfilled where concentration per unit area of impurity contained in the channel films becomes larger for MISFETs of a thicker channel film thickness. As a result, it is possible to suppress deviation of threshold voltage caused by changes in channel film thickness. In this event, designed values for the channel film thicknesses of the plurality of MISFETs are preferably the same, and the difference in channel film thickness of each MISFET may depend on statistical variation from the designed values. The concentration of the impurity per unit area is proportional to the channel film thickness, or is a function that is convex downwards with respect to the channel film thickness.
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