A regrowth is performed on {HEAD ~ the exposed surfaces} using {TAIL ~ an amphi conductivity impurity} as a dopant, such that a first portion having a first type conductivity is grown on the contact groove and a second portion having a second type conductivity is grown on the ridge 
A regrowth is performed on { HEAD ~ the exposed surfaces } using { TAIL ~ an amphi conductivity impurity } as a dopant , such that a first portion having a first type conductivity is grown on the contact groove and a second portion having a second type conductivity is grown on the ridge
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH