CMOS image converter with rear bias for wideband imaging

Abstract

Complementary metal-oxide-semiconductor (CMOS) image sensor, comprising: i) a bias junction consisting of a first semiconductor material type and electrically coupled to a voltage source to apply a reverse bias of opposite polarity to a polarity of the first semiconductor material type to the bias junction; ii) a pixel in a pixel array, comprising: a photosensitive element, a first well consisting of a second semiconductor material type, and a second well consisting of the first semiconductor material type, and active CMOS elements used for at least one of 1) reading and 2) resetting the image data acquired by the photosensitive element; and iii) an implanted, buried layer consisting of the second semiconductor material type, extending over a region representing the pixel array below the second well consisting of the first semiconductor material type;wherein the implanted, buried layer, which consists of the second semiconductor material type, is arranged to interact with the blocking bias applied by the voltage source to the bias junction to reduce a parasitic current path between the second well, which consists of the first semiconductor material type and is used by the active CMOS elements, and a substrate, resulting in more uniform pixel-to-pixel performance in an image sensor with two or more pixels.