Abstract: An image (or other light) sensor has a reflective element under each light-sensing element. The reflective element is positioned to reflect incident light that passes through the light-sensing element without being absorbed, back towards the light-sensing element for a second chance at being absorbed. The present invention increases the effective quantum efficiency of each light-sensing element without having to increase the thickness of the absorption region within the light-sensing element. In one embodiment, each reflective element is a discrete mirror that is positioned within the sensor packaging adjacent to (e.g., below) the integrated image sensor. In another embodiment, each reflective element is an integral part of the integrated circuit that contains the image sensor, such as a light-reflecting region formed within the substrate below the corresponding light-sensing element.

Abstract: Photo-sensors, such as photo-diodes, are formed using regions with cross-sections that increase the overall quantum efficiency of the resulting photo-sensor. The cross-sections have additional (e.g., interior) side-wall interfaces, and, in some embodiments, an additional, relatively shallow bottom interface. The increased total side-wall area and any additional shallow bottom area increase the total photo-junction volume located near the surface of the device. As a result, a greater fraction of photons having relatively small absorption lengths (e.g., blue light) will be absorbed within a photo-junction, thereby increasing the quantum efficiency for those photons. The present invention enables photo-sensors to be implemented with more uniform spectral response.

Abstract: Photo-sensors, such as photo-diodes, are formed using regions having layout shapes that tend to decrease leakage associated with high electric field strengths and mechanical stresses along the region's non-horizontal edges. According to one characterization of the present invention, the regions have a layout shape having more than four sides, in which all interior angles between adjacent sides of the layout shape are greater than 90 degrees. According to another characterization, the regions have a layout shape having at least one pair of mutually orthogonal sides with an intervening side that forms two interior angles greater than 90 degrees with the mutually orthogonal sides. Under either characterization, the electric field strengths and the mechanical stresses along the non-horizontal edges of the region defined by the adjacent sides of the layout shape, are reduced, thereby reducing leakage and increasing the overall quantum efficiency of the resulting photo-sensors.

Abstract: The presently preferred embodiment of the invention comprises a single ended bit-line from each pixel, small swing bit-line detection, a regenerative sense amplifier, and reference generation using precision analog references.