A regrowth is performed on the exposed surfaces using an amphi conductivity impurity as a dopant, such that {HEAD ~ 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 {TAIL ~ the ridge} 
A regrowth is performed on the exposed surfaces using an amphi conductivity impurity as a dopant , such that { HEAD ~ 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 { TAIL ~ the ridge }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL