Further, by varying the thickness of either layer and controlling the dopant concentration based on, for example, an epitaxial growth rate, {HEAD ~ a variety} of {TAIL ~ preprogrammed dopant profiles} may be obtained 
of
Further , by varying the thickness of either layer and controlling the dopant concentration based on , for example , an epitaxial growth rate , { HEAD ~ a variety } of { TAIL ~ preprogrammed dopant profiles } may be obtained
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH