{HEAD ~ An epitaxial layer} having an impurity concentration different from that of {TAIL ~ the impurity layer} is formed in the etched portion 
{ HEAD ~ An epitaxial layer } having an impurity concentration different from that of { TAIL ~ the impurity layer } is formed in the etched portion
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH