Pixel unit group of cmos image sensor and cmos image sensor

Abstract

The invention discloses a pixel unit of a complementary metal oxide semiconductor (CMOS) image sensor and the CMOS image sensor. According to the pixel unit of the CMOS image sensor, four pixels are arranged to form a 2*2 pixel array stricture which is used as a group of the pixel unit, wherein two pixels in a first line and two pixels in a second line share a line selection transistor, a source following transistor, a resetting transistor and a floating diffusion area in a line, and the two pixels in the first line and the two pixels in the second line form a back-to-back arrangement structure; and a plurality of pixel units are arranged in vertical and horizontal directions to form a two-dimensional pixel array. In the pixel array, a sequential control metal line of a grid of the line selection transistor is eliminated, and a power line and a line pixel signal output line share one metal line, so that the pixel array can effectively improve the light utilization efficiency of a small-area pixel sensor; therefore, the sensitivity is improved; and the image quality of the small-area pixel image sensor is effectively improved.

Description

technical field [0001] The invention relates to a CMOS image sensor, in particular to a pixel unit group and a CMOS image sensor using small-area pixels of the CMOS image sensor. Background technique [0002] Image sensors are already widely used in digital cameras, mobile phones, medical devices, automobiles and other applications. In particular, the rapid development of CMOS (Complementary Metal Oxide Semiconductor) image sensors has made people have higher requirements for low power consumption, small size, and high resolution image sensors. [0003] The pixel structure arrangement of CMOS image sensors in the prior art takes 4T2S (four transistors and two pixels shared) as an example. Because it depends on the structural characteristics of the pixel itself, its two-dimensional pixel array generally requires a row decoder to control the metal lines. Connected to the gates of the charge transfer transistor, the row selection transistor and the reset transistor respectivel...

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Problems solved by technology

[0004] The above-mentioned existing technologies have at least the following disadvantages: due to the small photosensitive area and low sensitivity of the small-sized pixel sensor, the information transmitted under dark light is not clear enough, especially the use of multiple metal interconnection lines in the pixel array, resulting in the opening of the metal window. The low efficiency blocks part of the light from entering the photodiode, thus affecting the clarity of the image

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