A second dopant zone with a doping of {HEAD ~ a second conductivity type} is formed in a second region of {TAIL ~ the semiconductor layer} 
A second dopant zone with a doping of { HEAD ~ a second conductivity type } is formed in a second region of { TAIL ~ the semiconductor layer }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL