Pixel cell and method for forming same and digital camera imaging system

Abstract

A pixel cell has a first substrate, one or more transfer transistors, a reset transistor, a capacitor, an amplifier transistor and a readout circuit block. The photodiode, transfer transistor, reset transistor and the amplifier transistor are disposed within a first substrate of a first semiconductor chip for accumulating an image charge in response to light incident upon the photodiode. The readout circuit block may be partially disposed within a second substrate of a second semiconductor chip and partially disposed within the first substrate wherein the readout circuit block comprises optionally selectable rolling shutter and global shutter readout modes through the use of computer programmable digital register settings. The global shutter readout mode provides in-pixel correlated doublesampling.

Description

technical field [0001] The invention relates to an image sensor, in particular to a pixel unit of a CMOS image sensor with a stacked chip structure. The bottom chip includes a photosensitive area and an array of structures to capture images. The top chip includes circuit elements to acquire images from the array. Image sensors can be used in digital cameras. Background technique [0002] An image capture device generally includes an image sensor and a lens. The lens focuses light onto the image sensor to form an image, and the image sensor converts the light signal into an electrical signal. Electrical signals are output from the image capture device to other components of the electronic system. The image capture device and other components of the electronic system make up the image system. Image sensors are becoming more common and can be found in various electronic systems, such as mobile phones, digital cameras, medical equipment, and computers. [0003] A typical i...

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