Patent ID: 7217968
Filing Date: 2007-05-15
Classification: H01L

Abstract:
1. An active pixel sensor (APS) cell structure comprising: a substrate having an upper surface; a gate comprising a dielectric layer formed on the substrate and a gate conductor formed on the gate dielectric layer; a collection well layer of a first conductivity type formed below a surface of said substrate adjacent a first side of said gate conductor, a pinning layer of a second conductivity type formed atop the collection well at a surface of said substrate, said pinning layer and collection well layer forming part of a photodiode structure for said APS cell, and a diffusion region of a first conductivity type having at least a portion formed at said upper surface of said substrate and adjacent a second side of said gate conductor, said gate conductor forming a channel region enabling charge transfer between said collection well layer and said diffusion region, wherein a portion of the gate conductor is recessed below the surface to a depth such that the bottom of the gate conductor us below the collection well.