A semiconductor layer with a doping of {HEAD ~ a second conductivity type} is applied at a surface of {TAIL ~ the semiconductor substrate} 
A semiconductor layer with a doping of { HEAD ~ a second conductivity type } is applied at a surface of { TAIL ~ the semiconductor substrate }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL