After distributing a nonmetal element in a region in {HEAD ~ the vicinity} of {TAIL ~ a surface portion} of a semiconductor layer, a metal film is deposited on the semiconductor layer 
After distributing a nonmetal element in a region in { HEAD ~ the vicinity } of { TAIL ~ a surface portion } of a semiconductor layer , a metal film is deposited on the semiconductor layer
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH