This is done by forming {HEAD ~ a pinned photodiode} which has a selective connection to {TAIL ~ the substrate} 
This is done by forming { HEAD ~ a pinned photodiode } which has a selective connection to { TAIL ~ the substrate }
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL