A power cell includes a fin over a substrate, the fin extending in a direction substantially perpendicular to a bottom surface of the substrate. The fin includes a first dopant type. The power cell further includes at least one isolation region over the substrate between the fin and an adjacent fin. The power cell further includes a gate structure in contact with the fin and the at least one isolation region, wherein the gate structure comprises a doped region in the fin, wherein the doped region has a second dopant type different from the first dopant type and the doped region defines a channel region in the fin.