Patent ID: 6806522
Filing Date: 2004-10-19
Classification: H01L

Abstract:
A Complementary Metal Oxide Semiconductor (CMOS) image sensor having a cell array portion in which single cells are disposed in an array and a peripheral circuit portion that controls said cell array, said CMOS image sensor comprising:a peripheral circuit portion comprising a plurality of circuits formed on a silicon substrate and disposed on a periphery of said cell array portion; p1 a plurality of single cells serving as photosensors in said cell array, each said cell including a buried photodiode structure comprising: a first cell diffusion region formed on said silicon substrate, said first cell diffusion region having a same conductivity type as a conductivity type of said silicon substrate; a second cell diffusion region directly below said first cell diffusion region, said second cell diffusion region having a conductivity type different than a conductivity type of said silicon substrate; a third cell diffusion region underlying said second cell diffusion region, said third cell diffusion region comprising a deep well region having a same conductivity type as said silicon substrate; and a fourth cell diffusion region contacting said third cell diffusion region and serving as a sidewall well region that surrounds said second cell diffusion region, said fourth cell diffusion region having a same conductivity type as said silicon substrate; and a noise charge absorption region provided on the periphery of said cell or said cell array portion, said noise charge absorption region including a diffusion layer formed on said silicon substrate, wherein said diffusion layer is connected to a constant potential, said diffusion layer having a conductivity type different than a conductivity type of said silicon substrate, and wherein said noise charge absorption region collects stray charges generated by said peripheral circuit portion.