{HEAD ~ A thick insulator region} is formed on {TAIL ~ a portion} of the drift region at the face 
{ HEAD ~ A thick insulator region } is formed on { TAIL ~ a portion } of the drift region at the face
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH