IMAGE SENSOR PIXEL HAVING PINNED PHOTODIODE WITH COUPLING CAPACITOR AND METHOD FOR SENSING A SIGNAL THEREOF

摘要

An image sensor pixel including pinned photodiode using a coupling capacitor is provided to reduce a dark current generated from an ohmic contact by using a coupling capacitor to transfer a signal voltage to an amplifier without using an ohmic-contacted floating diffusion sensing node. A first diffusion region of a second conductivity type is formed in an epitaxial layer of a first conductivity type. A second diffusion region of the first conductivity type is formed on the first diffusion region. A third diffusion region of the second conductivity type is formed in the epitaxial layer, electrically connected to the first diffusion region. A fourth diffusion region of the first conductivity type floats in the third diffusion region. A coupling capacitor(CC) transfers the voltage variation of the third diffusion region to the outside, connected to the fourth diffusion region. The first diffusion region physically comes in contact with the third diffusion region.