Photosensitive capacitor pixel for image sensor

Abstract

A method of fabricating a pixel array includes forming a transistor network along a frontside of a semiconductor substrate. A contact element is formed for every pixel in the pixel array that is electrically coupled to a transistor within the transistor network. An interconnect layer is formed upon the frontside to control the transistor network with a dielectric that covers the contact element. A cavity is formed in the interconnect layer. A conductive layer is formed along cavity walls of the cavity and a dielectric layer is formed over the conductive layer within the cavity. A photosensitive semiconductor material is deposited over the dielectric layer within the cavity. An electrode cavity is formed that extends into the contact element. The electrode cavity is at least partially filled with a conductive material to form an electrode. The electrode, the conductive layer, and the photosensitive semiconductor material form a photosensitive capacitor.