A fourth semiconductor region of {HEAD ~ the second conductivity type} is disposed on the second semiconductor well and in {TAIL ~ electrical communication} with the circuit electrode 
A fourth semiconductor region of { HEAD ~ the second conductivity type } is disposed on the second semiconductor well and in { TAIL ~ electrical communication } with the circuit electrode
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH