Trench isolation structure, manufacturing method thereof, semiconductor device, and image sensor

Abstract

The present invention discloses a trench isolation structure, a production method thereof, a semiconductor device and an image sensor. The trench isolation structure comprises a shallow trench arranged in a substrate, an isolation material layer arranged in the shallow trench, and an epitaxial structure arranged between the shallow trench and the isolation material layer. The epitaxial structure comprises at least one epitaxial layer formed by in-situ doping. The epitaxial layer is formed by outward deposition of the inner wall of the shallow trench, a closed combined interface can be formed by the epitaxial layer and the inner surface of the shallow trench, and thus the leakage current generated by the combination part between the inner wall of the shallow trench and the epitaxial layer is avoided. At the same time, the composition or structure of the epitaxial layer can be changed through the mode of in-situ doping, thus the migration of a carrier in the epitaxial layer is reduced further, and the leakage in a semiconductor device is reduced further.

Description

technical field [0001] The present application relates to the technical field of manufacturing semiconductor integrated circuits, and in particular, relates to a trench isolation structure, a manufacturing method thereof, a semiconductor device, and an image sensor. Background technique [0002] In a semiconductor device, an isolation structure needs to be provided between different devices to isolate the devices. Among them, the trench isolation structure has become one of the most commonly used isolation structures in semiconductor devices due to its advantages of good isolation effect and simple manufacturing process. The existing trench isolation structure usually includes a shallow trench disposed in the substrate, and an isolation material layer disposed in the shallow trench. During the actual operation of this trench isolation structure, since the carriers in the substrate around the shallow trench will migrate to the inner surface of the shallow trench, leakage cur...

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Problems solved by technology

However, in this method, the ion implantation process will be blocked by other device structures on the substrate (such as photoresist, etc.), resulting in uneven distribution of implanted ions in the implanted region

And this uneven distribution can lead to leakage current in the trench isolation structure

At the same time, in the above method, the ion implantation process may cause damage to the substrate and other devices, thereby further reducing the performance of the semiconductor device.

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