Transparent conductor based pinned photodiode

Abstract

A pinned photodiode with improved short wavelength light response. In exemplary embodiments of the invention, a gate oxide is formed over a doped, buried region in a semiconductor substrate. A gate conductor is formed on top of the gate oxide. The gate conductor is transparent, and in one embodiment is a layer of indium-tin oxide. The transparent conductor can be biased to reduce the need for a surface dopant in creating a pinned photodiode region. The biasing of the transparent conductor produces a hole-rich accumulation region near the surface of the substrate. The gate conductor material permits a greater amount of charges from short wavelength light to be captured in the photo-sensing region in the substrate, and thereby increases the quantum efficiency of the photosensor.

Dependencies are inferred from the claim text.