Semiconductor device, forming method thereof and image sensor

Abstract

The invention provides a semiconductor device, a forming method thereof and an image sensor. The forming method of the semiconductor device comprises the following steps: providing a substrate, and forming densely distributed inverted triangular grooves in the surface of one side of the substrate; carrying out pretreatment of maskless etching and / or maskless ion implantation on the substrate to enable the surface of the inverted triangular groove to become rough; and performing acid etching on the surface of the roughened inverted triangular groove to form a textured structure on the surface of the roughened inverted triangular groove. The densely distributed inverted triangular grooves form a 'large suede' structure on the surface of the substrate, so the length of an optical path in a silicon wafer of the image sensor is increased, the effective optical path length is prolonged in the silicon wafer, and the light absorption efficiency is improved. A suede structure is formed on the surface of the inverted triangular groove and is of a 'small suede' structure, the reflection frequency of light in the substrate is further increased, and therefore the quantum efficiency of the device is greatly improved.

Description

technical field [0001] The invention belongs to the technical field of integrated circuit manufacturing, and in particular relates to a semiconductor device, a forming method thereof, and an image sensor. Background technique [0002] For silicon-based semiconductor devices (such as optoelectronic devices), the surface reflectivity of silicon is very high. If no treatment is performed on the silicon surface, its reflectivity to visible light can reach more than 40%, and the reflectivity to near-infrared light The reflectivity is as high as 60%. The reflectivity of crystalline silicon to light is so high that the quantum efficiency of related optoelectronic devices made of crystalline silicon is very unsatisfactory, which ultimately seriously restricts the application fields and performance of optoelectronic products. [0003] The principle of optoelectronic chip application is the absorption of light by materials. However, the absorption of light by materials is conditiona...

AI Technical Summary

Problems solved by technology

From visible light to near-infrared light, the absorption efficiency of crystalline silicon for photons gradually decreases. Even though crystalline silicon has a good absorption efficiency for the visible light range of traditional CMOS image sensors (CIS), as light waves change from visible light to near-infrared light, silicon The problem of photon absorption will become more and more prominent, and must attract the attention and attention of engineers and technicians

The photon absorption efficiency of the material can be improved by increasing the thickness of silicon, but the increase in the thickness of silicon will bring a very huge challenge to the semiconductor process, and its cost performance is not high

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