a first gate electrode of {HEAD ~ a first MOS transistor} of {TAIL ~ a first conductivity type} formed on said primary surface of said substrate 
a first gate electrode of { HEAD ~ a first MOS transistor } of { TAIL ~ a first conductivity type } formed on said primary surface of said substrate
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH