Global shutter image sensor unit and preparation method thereof

Abstract

The invention discloses a global shutter image sensor unit. The global shutter image sensor unit comprises a substrate, and a shallow slot isolation region, a transmission transistor gate, a photodiode and a floating diffusion region which are arranged on the substrate, and a conductive light blocking layer arranged above the substrate, wherein the conductive light blocking layer is adjacently located above the floating diffusion region and completely covers the floating diffusion region, a lower surface of the conductive light blocking layer is connected with an upper surface of the floatingdiffusion region, and an upper surface of the conductive light blocking layer is connected with a metal interconnection layer arranged above the substrate. The global shutter image sensor unit is advantaged in that through a lightproof silicide conductive light blocking layer arranged above a storage node capacitor of the floating diffusion region, the floating diffusion region is effectively prevented from being influenced by illumination, and the parasitic light response of the global shutter image sensor unit is reduced.

Description

technical field [0001] The invention relates to the technical field of image sensors, in particular to a global shutter image sensor unit and a preparation method thereof. Background technique [0002] An image sensor refers to a device that converts optical signals into electrical signals. Image sensor unit categories mainly include Charge Coupled Device (CCD) and Complementary Metal Oxide Semiconductor (CMOS) devices. Compared with traditional CCD sensors, CMOS image sensors have the characteristics of low power consumption, low cost, and compatibility with CMOS technology, so they are more and more widely used. [0003] The CMOS image sensor includes a pixel array composed of many pixel units, and the pixel unit is the core device for the image sensor to realize light sensing. In the CMOS image sensor, the exposure time is usually controlled by an electronic shutter. According to different working principles, the electronic shutter is divided into two types: drum type a...

AI Technical Summary

Problems solved by technology

However, since there is a gap in the dielectric isolation layer 106 between the metal interconnection layer 107 and the floating diffusion region 104, and the dielectric layer has a relatively good light transmittance, this allows light leakage from the side to reach the floating diffusion region The PN junction of 104 generates photo-generated electrons and affects the signal of the storage node

Images