Image sensor and forming method thereof

Abstract

The invention discloses an image sensor and a forming method thereof. The method comprises the following steps: providing a substrate; patterning the substrate to form a plurality of columnar structures distributed in an array mode, first deep grooves are formed among the columnar structures arranged in the first direction, second deep grooves are formed among the columnar structures arranged in the second direction, and crossed deep grooves are formed among the columnar structures arranged in the third direction, the side wall, perpendicular to the first direction, of the columnar structure is a (110) crystal face, and the diagonal plane, perpendicular to the third direction, of the columnar structure is a (100) crystal face; and forming doped epitaxial layers in the first deep trench, the second deep trench and the crossed deep trench. Through the arrangement that the side wall, perpendicular to the first direction, of the columnar structure is the (110) crystal face, and the diagonal plane, perpendicular to the third direction, of the columnar structure is the (100) crystal face, the defect generated when the crossed deep grooves are filled with the final seal can be obviously overcome, white noise is effectively reduced, and the performance of the finally formed image sensor is improved.

Description

technical field [0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular, to an image sensor and a method for forming the same. Background technique [0002] Image sensors are semiconductor devices that convert optical images into electrical signals. Because of the advantages of low power consumption and high signal-to-noise ratio, CMOS image sensors (CMOS Image Sensor, CIS) have been widely used in various fields. [0003] The most commonly used Pixel unit in a CMOS image sensor contains a photodiode PD and four MOS transistors, including a transfer transistor TX, a reset transistor RST, a source follower transistor SF, a row select transistor RS, and a floating diffusion region FD, which can realize the photoelectric Control of selection, reset, signal output, signal amplification and readout of diode PD. The principle is that when light illuminates the photodiode PD, the photodiode PD will generate the accumulation of ...

AI Technical Summary

Problems solved by technology

[0004] However, there are still many problems in the formation process of the prior art CMOS image sensor

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