Patent ID: 8743247

Claim:
A method of forming an active pixel sensor (APS) cell structure comprising the steps of: providing a substrate of a first conductivity type material; forming a gate dielectric layer on the substrate; forming a gate conductor structure on the gate dielectric layer, said gate conductor structure comprising a first doped region of first conductivity type material including an associated first transfer gate electrode and a second doped region of a second conductivity type material including an associated second transfer gate electrode, wherein the first doped region of the first conductivity type material and the second doped region of the second conductivity type material are in direct contact, wherein the gate conductor structure further comprises separate conductors to each of said first and second transfer gate electrodes to apply separate voltage signals to each of said first and second transfer gate electrodes by direct electrical contact to each of the first and second doped regions; forming a photosensing device formed at or below a substrate surface adjacent said first doped region of said gate conductor structure for collecting charge carriers in response to light incident thereto; and forming a diffusion region of a second conductivity type material at or below said substrate surface adjacent said second doped region of said gate conductor structure, said gate conductor structure defining a channel region in said substrate for enabling charge transfer between said photosensing device and said diffusion region, said first and second transfer gate electrodes for receiving said separate voltage signals timed for transferring collected charge carriers from said photosensing device to said diffusion region while preventing spillback of charges to said photosensing device.