A first semiconductor well of {HEAD ~ the second conductivity type} is disposed in {TAIL ~ the semiconductor material} 
A first semiconductor well of { HEAD ~ the second conductivity type } is disposed in { TAIL ~ the semiconductor material }
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL