An integrated structure includes a first MOS transistor with a first controllable gate region overlying a first gate dielectric and a second MOS transistor neighboring the first MOS transistor and having a second controllable gate region overlying the first gate dielectric. A common conductive region overlies the first and second gate regions and is separated therefrom by a second gate dielectric. The common conductive region includes a continuous element located over a portion of the first and second gate regions and a branch extending downward from the continuous element toward the substrate as far as the first gate dielectric. The branch located between the first and second gate regions.