Texas Instruments Incorporated
Integrated photodetector

Abstract:

An integrated circuit that includes a substrate, a photodiode, and a Fresnel structure. The photodiode is formed on the substrate, and it has a p-n junction. The Fresnel structure is formed above the photodiode, and it defines a focal zone that is positioned within a proximity of the p-n junction. In one aspect, the Fresnel structure may include a trench pattern that functions as a diffraction means for redirecting and concentrating incident photons to the focal zone. In another aspect, the Fresnel structure may include a wiring pattern that functions as a diffraction means for redirecting and concentrating incident photons to the focal zone. In yet another aspect, the Fresnel structure may include a transparent dielectric pattern that functions as a refractive means for redirecting and concentrating incident photons to the focal zone.