Image sensor and method for forming same

Abstract

The present disclosure relates to an image sensor and a method for forming the same. The method for forming the image sensor comprises the steps of: providing a substrate including an active region ofa first doping type; forming, over the active region, at least one photoelectric sensing component and full isolation structures surrounding respective photoelectric sensing components, wherein eachfull isolation structure includes a first trench isolation structure extending in a direction perpendicular to the surface of the substrate and a second trench isolation structure over the first trench isolation structure, the first trench isolation structure is adjacent to the second trench isolation structure such that adjacent photoelectric sensing components are isolated from each other.

Description

technical field [0001] The present disclosure relates to the field of semiconductors, and in particular, to image sensors and methods of forming the same. Background technique [0002] An image sensor is a functional device capable of sensing radiation (eg, optical radiation, including but not limited to visible light, infrared rays, ultraviolet rays, etc.) and thereby generating corresponding electrical signals. Image sensors are widely used in various electronic products that need to sense radiation. [0003] An image sensor may include a plurality of pixel units, where each pixel unit has a photo-sensing component, such as a photodiode. The image sensor may include trench isolation structures disposed between adjacent pixel units for physical isolation, electrical isolation, and the like. For example, an image sensor may include a deep trench isolation (DTI) structure and / or a shallow trench isolation (STI) structure for isolating adjacent pixel units. [0004] Since i...

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Problems solved by technology

This will lead to many problems, for example, the light originally incident on a certain pixel unit may enter the adjacent pixel unit through the gap between the DTI structure and the corresponding STI structure, thereby causing serious light crosstalk (light crosstalk); another example, when When the incident light intensity is large and the number of photo-generated carriers is too large, the photo-generated carriers may overflow to adjacent pixel units, resulting in an unfavorable blooming effect.

These problems will aggravate the optical crosstalk and electrical crosstalk between pixels, resulting in poor imaging quality and other performance of the image sensor.

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