Patent ID: 6730914
Filing Date: 2004-05-04
Classification: H01L

Abstract:
An active pixel sensor for producing images from electron-hole producing radiation comprising:A) a solid state radiation detection unit comprising: 1) a crystalline semiconductor substrate; 2) a plurality of Complementary Metal Oxide Semiconductor pixel circuits incorporated into said substrate to form an array of pixel circuits, wherein each of said array of pixel circuits comprises: a) a charge collecting pixel electrode; b) a charge sensing node; c) a gate bias transistor separating said charge collecting pixel electrode and said charge sensing node and maintaining said pixel electrodes at substantially equal potential; d) a pixel capacitor comprising said charge collecting pixel electrode and said charge sensing node, wherein said pixel capacitor is configured to store charges collected by said charge collecting pixel electrode; e) a charge measuring circuit comprising at least one transistor, wherein a gate of said at least one transistor is electrically connected to said charge sensing node; 3) a radiation absorbing layer comprised of photconductive material covering at least a portion of said array of pixel circuits, wherein said photoconductive material is photoconductive on exposure to said electron-hole producing radiation; 4) a surface electrode layer comprised of electrically conducting material and formed on said radiation absorbing layer, wherein said surface electrode 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 layer and between said surface electrode layer and each of said array of charge collecting pixel electrodes; and B) 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.