CMOS image sensor

Abstract

The embodiment of the invention provides a CMOS image sensor and relates to the technical field of semiconductors. The CMOS image sensor can achieve high-sensitivity and high-speed responses. Each pixel unit of the CMOS image sensor comprises a P type semiconductor substrate, a first N type ion layer on the upper portion of the P type semiconductor substrate, a P trap surrounding the first N type ion layer, a second N type ion layer, a third N type ion layer, a first P type ion layer and a second P type ion layer, wherein the second N type ion layer, the third N type ion layer, the first P type ion layer and the second P type ion layer are arranged on the upper portion of the first N type ion layer; the first P type ion layer and the second P type ion layer are spaced by the second N type ion layer, the second N type ion layer and the third N type ion layer are spaced by the second P type ion layer, the doping concentration of the second N type ion layer and the doping concentration of the third N type ion layer are larger than the doping concentration of the first N type ion layer, and the doping concentration of the first P type ion layer and the doping concentration of the second P type ion layer are between the doping concentration of the P trap and the doping concentration of the P type semiconductor substrate. The CMOS image sensor is used for sensor manufacturing.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a CMOS image sensor. Background technique [0002] The image sensor is an important part of the digital camera, which can be divided into two categories: CMOS (Complementary Metal-Oxide Semiconductor, Complementary Metal-Oxide Semiconductor) image sensor and CCD (Charge Coupled Device, Charge Coupled Device) image sensor. Compared with CCD image sensors, CMOS image sensors have many advantages such as low cost, low power consumption, and high integration, and are widely used in various electronic products. [0003] In the prior art, the structure of the pixel unit of the CMOS image sensor is as follows figure 1 As shown, it mainly includes a photodiode 1 for photoelectric signal conversion, a floating point diffusion area 2 for accumulating photogenerated electrons generated in the photodiode 1; a floating point diffusion area 2 for resetting the floating point diffusion ...

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Problems solved by technology

[0004] However, in the above-mentioned CMOS image sensor, the floating diffusion area (Floating Diffusion, referred to as FD) has a large volume, so the number of electrons that can be accommodated is relatively large, and the number of electrons that need to be filled is also relatively large; This will lead to a longer response time of the CMOS image sensor, which will adversely affect the speed and sensitivity of its response.

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