patterning the layer of dielectric material to expose at least one portion of {HEAD ~ the semiconductor substrate} overlying {TAIL ~ the channel region} 
patterning the layer of dielectric material to expose at least one portion of { HEAD ~ the semiconductor substrate } overlying { TAIL ~ the channel region }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL