A MOS transistor formed in a silicon substrate comprising an active area surrounded with an insulating wall, a first conductive strip covering a central strip of the active area, one or several second conductive strips placed in the active area right above the first strip, and conductive regions placed in two recesses of the insulating wall and placed against the ends of the first and second strips, the silicon surfaces opposite to the conductive strips and regions being covered with an insulator forming a gate oxide.