The method 12, wherein the boron doped region is formed by {HEAD ~ solid state diffusion} and {TAIL ~ etching} 
The method 12 , wherein the boron doped region is formed by { HEAD ~ solid state diffusion } and { TAIL ~ etching }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL