FD active region structure for pixel unit, preparation and CMOS image sensor thereof

Abstract

The invention discloses an FD active region structure of a pixel cell, which belongs to the field of CMOS image sensors. The FD active region structure comprises a P type well formed on a P type silicon semiconductor substrate, the P type well is equipped with an N type silicon semiconductor injection layer, the N type silicon semiconductor injection layer comprises an N-Plus ion implanted layer, a P type silicon semiconductor injection layer is arranged surrounding the N type silicon semiconductor injection layer, the P type silicon semiconductor injection layer is used to separate the N type silicon semiconductor injection layer and a shallow trench isolation area STI of a device, the N type silicon semiconductor injection layer is equipped with a P type silicon semiconductor Pin layer, and the bottom portion of a buried type contact hole penetrates through the P type silicon semiconductor Pin layer to electrically connect with the N type silicon semiconductor injection layer. Through adding the N-Plus implanted layer in the N type silicon semiconductor injection layer of the FD active region of the pixel cell, adding the P type silicon semiconductor injection layer surrounding the N type silicon semiconductor injection layer, and adding the Pin injection layer on the N type silicon semiconductor injection layer, drain current in the FD active region can be effectively reduced.

Description

technical field [0001] The invention relates to the field of image sensors, in particular to an FD active region structure capable of reducing leakage current of pixel units in a CMOS image sensor, a preparation method thereof, and a CMOS image sensor. Background technique [0002] With the development of solid-state image sensors, CMOS image sensors have many advantages over CCD image sensors, such as low cost, low power consumption, and high functional integration, and have been developed rapidly. They are widely used in digital cameras, mobile phones and other various in consumer electronics products. CMOS image sensors use photodiodes to convert light signals into electrical signals, and then process and store the electrical signals as data for image restoration. [0003] As an important part of the pixel unit Pix1 of the CMOS image sensor, the structure and preparation method of the FD (Floating Diffusion) active region affect the quality of the signal charge. The FD a...

AI Technical Summary

Problems solved by technology

However, with the continuous development of image technology, people have higher requirements for the image definition of high-speed moving objects, and when taking pictures of high-speed moving objects, it is required that the pixel array of the CMOS image sensor should work in the global exposure acquisition signal. However, due to the limitation of the FD active region structu

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