Pixel unit with wide dynamic range, manufacturing method thereof, and image sensor formed by same

Abstract

The invention provides a pixel unit with a wide dynamic range, a manufacturing method thereof, and an image sensor formed by the same. The pixel unit comprises a photoelectric diode, a transmission gate transistor, a floating diffusion node, a reset resistor, a source follower transistor and a row gate transistor which are formed on the same substrate. The pixel unit further comprises a PINNED structure connected with the floating diffusion node. The pixel unit realizes the nonlinear sensitivity of the image sensor through controlling depletion voltage of the PINNED structure. The manufacturing method is simple in process and compatible with the CMOS manufacturing process in the prior art. The image sensor provided by the invention adopts the pixel unit with the PINNED structure to form a pixel array, realizes the nonlinear sensitivity of the image sensor, not only can improve control for an overexposed area by the image sensor, but also can improve the visibility of a dark area, thereby improving the dynamic range of the image sensor.

Description

technical field [0001] The invention belongs to the field of basic electrical components and relates to the preparation of semiconductor devices, in particular to a pixel unit with a wide dynamic range, a manufacturing method of the pixel unit and an image sensor composed of the pixel unit. Background technique [0002] In recent years, the CMOS image sensor industry has developed rapidly. Image sensor manufacturers have introduced products with superior performance and smaller chip area. With the reduction of pixel size, the cost has been greatly reduced, but some performance has been significantly restricted, such as dynamic range and sensitivity. , signal-to-noise ratio, etc. In order to improve the dynamic range of the chip, large and small pixels or pixels with a large and small FD (floating diffusion node) structure are mainly used to achieve a wide dynamic range. In the large and small pixel method, one pixel unit contains two pixels - a large pixel and a small pixel...

AI Technical Summary

Problems solved by technology

Although the above method can realize a wide dynamic image sensor, but in the case of the same resolution, the chip area of ​​the image sensor will be additionally increased, and the cost performance is low.

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