Patent ID: 7087944

Claim:
An image sensor comprising: a substrate having a first dopant concentration; a photosensor for collecting charges in a charge collection region of a first conductivity type located within a doped layer of a second conductivity type of said substrate, said charge collection region extending vertically within said substrate to a first depth, a gate structure of a transistor formed over said substrate for gating charges collected by said charge collection region; an implanted region of said second conductivity type, having a second dopant concentration, within said substrate, wherein said implanted region is located laterally of said photosensor and adjacent said charge collection region, and wherein said implanted region extends vertically within said substrate to a second depth which is greater than said first depth; and a charge storage region of said first conductivity type formed in said implanted region for receiving charges gated by said gate structure, wherein said first dopant concentration and said second dopant concentration are unequal.