A semiconductor device includes two Dt-MOS transistors each having insulation regions respectively under the source and drain regions, the two Dt-MOS transistors sharing a diffusion region as a source region of one Dt-MOS transistor and a drain region of the other Dt-MOS transistor, wherein the insulation regions have respective bottom edges located lower than bottom edges of respective body regions of the Dt-MOS transistors, and wherein the bottom edges of the respective body regions are located deeper than respective bottom edges of the source and drain regions of the Dt-MOS transistors.