{TAIL ~ a silicon nitride liner} on the sidewalls and on the top surface of {HEAD ~ each gate electrode} 
{ TAIL ~ a silicon nitride liner } on the sidewalls and on the top surface of { HEAD ~ each gate electrode }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD