Patent ID: 7692134

Claim:
An apparatus, comprising: a light sensor cell disposed in a substrate, the light sensor cell having: a photosensitive element; a floating diffusion region; a gate oxide disposed between the photosensitive element and the floating diffusion region, the gate oxide having at least a first and a second thicknesses; wherein the first thickness of the gate oxide is in proximity to the photosensitive element and the second thickness of the gate oxide is in proximity to the floating diffusion region; and the first thickness of the gate oxide is greater than the second thickness of the gate oxide; and a transfer gate disposed on the gate oxide between the photosensitive element and the floating diffusion region, wherein the first thickness of the gate oxide extends from the substrate to the transfer gate and wherein the second thickness of the gate oxide extends from the substrate to the transfer gate, and wherein the first thickness and the second thickness generate a driving force to accelerate the flow of electrons from the photosensitive element toward the floating diffusion region.