Patent ID: 7973342
Filing Date: 2011-07-05
Classification: H01L

Abstract:
1. A CMOS image sensor including a photodiode and a plurality of transistors, the CMOS image sensor comprising: a first conductive type semiconductor substrate, having an active area including a photodiode area, a floating diffusion area, and a voltage input/output area; a gate electrode of each of first, second and third transistors on the active area of the semiconductor substrate and a gate insulating layer between each gate electrode and the semiconductor substrate, wherein the gate electrode of the first transistor is over an interface between the photodiode area and the floating diffusion area, the gate electrode of the second transistor is over an interface between the floating diffusion area and the voltage input/output area, and the gate electrode of the third transistor is over the voltage input/output area; a first conductive type first well area in the semiconductor substrate corresponding to the voltage input/output area; a first conductive type second well area in the semiconductor substrate corresponding to the floating diffusion area, wherein the first conductive type first well area has (i) a doping density higher than a doping density of the first conductive type second well area and (ii) a greater depth than the first conductive type second well area; and a second conductive type diffusion area in the semiconductor substrate at opposed sides of each gate electrode.