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