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