An integrated chip comprises a substrate, an isolation structure and a gate structure. The isolation structure comprises one or more dielectric materials within the substrate and has sidewalls defining an active region in the substrate. The active region has a channel region, a source region, and a drain region separated from the source region by the channel region along a first direction. The source, drain and channel regions respectively have first, second and third widths along a second direction perpendicular to the first direction. The third width is larger than the first and second widths. The gate structure comprises a first gate electrode region having a first composition of one or more materials and a second gate electrode region having a second composition of one or more materials different than the first composition of one or more materials.