The doped regions can be formed by implanting {TAIL ~ first type dopants} into {HEAD ~ the substrate} 
The doped regions can be formed by implanting { TAIL ~ first type dopants } into { HEAD ~ the substrate }
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD