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