Semiconductor device and fabrication method thereof

摘要

The present invention suppresses the refresh failure of a DRAM due to the dispersion of a threshold of a MOSFET. The DRAM has a first unit for recording a set value of a back bias potential to be applied to a back gate of a cell transistor and a second unit for generating a back bias potential based on the set value of the back bias potential recorded in the first unit and supplying the generated back bias potential to the back gate, wherein when a threshold of a MOSFET which has a structure identical to the cell transistor and which has been fabricated in the same process as the cell transistor is greater than a target value which the cell transistor should have, a value shallower than the back bias potential for the target value is recorded in the second unit.