Patent ID: 8513753

Claim:
A photodiode pixel sensor, comprising: a buried well region of a first conductivity type formed within a portion of a semiconductor substrate of a second conductivity type opposite to the first conductivity type; a well region of the first conductivity type arranged upon and in contact with an upper surface of the buried well region, wherein the well region comprises a first net concentration of dopants greater than a second net concentration of dopants within the buried well region; a collection-junction of the first conductivity type in electrical contact with the well region, wherein the collection-junction comprises a third net concentration of dopants greater than the first net concentration of dopants within the well region; and a barrier material of the second conductivity type arranged over a majority of an upper surface of the buried well region and surrounding the well region and collection-junction on multiple sides; wherein the buried well region, the well region and the collection-junction form a series of three vertically positioned junctions having successively increasing net concentration of dopants from the semiconductor substrate.