Patent ID: 6791130
Filing Date: 2004-09-14
Classification: H01L

Abstract:
An active pixel sensor for producing images from electron-hole producing radiation comprising:a crystalline semiconductor substrate having an array of electrically conductive diffusion regions; an interlayer dielectric (ILD) layer formed over said crystalline semiconductor substrate and comprising an array of contact electrodes; an interconnect structure formed over said ILD layer, wherein said interconnect structure includes at least one layer comprising an array of conductive vias; an array of patterned metal pads formed over said interconnect structure; an array of charge collecting pixel electrodes defined by said array of diffusion regions, said array of contact electrodes, said array of conductive vias, and said array of patterned metal pads; a radiation absorbing structure comprising N-I-B-P photodiode layers formed over said interconnect structure and said array of patterned metal pads, wherein said N-I-B-P photodiode layers are photoconductive on exposure to electron-hole producing radiation; a surface lectrode layer comprising electrically conductive material and formed over said radiation absorbing layer, wherein said surface electrod layer is at least partially transparent to said electron-hole producing radiation, and connected to a voltage source for establishing an electrical field across said radiation absorbing structure and between said surface electrode layer and each of said array of charge collecting pixel electrodes, wherein said P-layer is electrically connected to said array of charge collecting pixel electrodes, and said N-layer is electrically connected to said surface electrode layer; and an array measurement circuit for measuring charges collected by each of said array of charge collecting pixel electrodes, and for outputting pixel data indicative of said collected charges, wherein said pixel data comprises information defining an image.