A MOS transistor is produced on and in an active zone which includes a source region and a drain region. The active zone is surrounded by an insulating region. A conductive gate region of the transistor has two flanks which extend transversely to a source-drain direction, and the conductive gate region overlaps two opposite edges of the active zone act overlap zones. The conductive gate region includes, at a location of at least one overlap zone, at least one conductive tag which projects from at least one flank at a foot of the conductive gate region. The conductive tag covers a part of the active zone and a part of the insulating region.