The drain region, {HEAD ~ the source/base region}, and the cathode region have {TAIL ~ a second conductivity type} 
The drain region , { HEAD ~ the source / base region } , and the cathode region have { TAIL ~ a second conductivity type }
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL