Patent ID: 7675097
Filing Date: 2010-03-09
Classification: H01L

Abstract:
1. An active pixel sensor (APS) cell structure comprising: a substrate of a first conductivity type material; a transfer gate device comprising a gate dielectric layer formed on the substrate and a dual workfunction gate conductor layer formed on the gate dielectric layer, said dual workfunction gate conductor layer comprising a first doped region of first conductivity type material and a second doped region of a second conductivity type material; a photosensing device formed at or below a substrate surface adjacent said first doped region of said transfer gate device for collecting charge carriers in response to light incident thereto; a diffusion region of a second conductivity type material formed at said substrate surface adjacent said second doped region of said transfer gate device, said transfer gate device forming a channel region enabling charge transfer between said photosensing device and said diffusion region; and, a silicide structure formed atop said dual workfunction gate conductor layer for electrically coupling said first doped region of first conductivity type material of said transfer gate device and said second doped region of second conductivity type material of said transfer gate device, wherein said silicide structure formed over said dual workfunction gate conductor layer for electrically coupling said first doped region of first conductivity type material and said second doped region of second conductivity type material of said transfer gate device is smaller in area dimension than an area dimension of said dual workfunction gate conductor layer.