A semiconductor device includes an SOI substrate having a base substrate material, an active semiconductor layer positioned above the base substrate material and a buried insulating material layer positioned between the base substrate material and the active semiconductor layer. A gate structure is positioned above the active semiconductor layer and a back gate region is positioned in the base substrate material below the gate structure and below the buried insulating material layer. An isolation region electrically insulates the back gate region from the surrounding base substrate material, wherein the isolation region includes a plurality of implanted well regions that laterally contact and laterally enclose the back gate region and an implanted isolation layer that is formed below the back gate region.