Patent ID: 7652313

Claim:
A pixel sensor comprising: a plurality of photosensitive elements formed at varying depths in a substrate, each photosensitive element including a p-n junction photodiode having a p-type layer and an n-type layer and being adapted to generate photocharges in response to electromagnetic radiation, and wherein the shallowest photosensitive element in the substrate includes a p-type layer residing above an n-type layer, wherein the shallowest p-type layer isolates the shallowest n-type layer from contact with a surface of the pixel sensor; and a plurality of photocharge transfer devices, a first photocharge transfer device being coupled to a first n-type cathode of a first photosensitive element and a second photocharge transfer device being coupled to a second n-type cathode of a second photosensitive element, wherein the second photosensitive element is located directly over the first photosensitive element, and wherein the second photosensitive element shares a p-type layer with the first photosensitive element.