Semiconductor device and forming method thereof

Abstract

The invention discloses a semiconductor device and a forming method thereof. The method comprises the steps of: providing a substrate, enabling the substrate to be provided with an initial gate structure, enabling the side wall surface of the initial gate structure to be provided with a side wall, enabling the initial gate structure and the substrate at two sides of the side wall to be internallyprovided with source-drain doped regions, and enabling the substrate to be provided with a dielectric layer covering the initial gate structure and the side wall, etching back a part of the initial gate structure to form a gate structure, and forming a gate opening in the dielectric layer, the top surface of the gate structure being lower than the top surface of the dielectric layer, and the sidewall of the gate opening exposing a part of the side wall, forming a protective layer in the gate opening, the protective layer covering the bottom surface and the side wall surface of the gate opening and the top surface of the dielectric layer, and the protective layer being made of a material different from that of the side wall, and after the protective layer is formed, forming an isolation structure in the gate opening, the material of the isolation structure being different from that of the protective layer. The semiconductor device formed by the method is good in performance.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a semiconductor device and a forming method thereof. Background technique [0002] A MOS (metal-oxide-semiconductor) transistor is an important semiconductor device. The basic structure of a MOS transistor includes: a semiconductor substrate; a gate structure located on the surface of the semiconductor substrate; a semiconductor substrate located on one side of the gate structure The source region and the drain region in the semiconductor substrate on the other side of the gate structure. [0003] With the further reduction of feature size, there are more and more process links that affect the performance and reliability of integrated circuits. At present, in the manufacturing process of semiconductor devices, contact holes (Contact, CT), as a channel connecting an active region of the device with an external circuit, play an important role in the composition of the de...

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Problems solved by technology

[0004] However, the contact holes formed in the prior art are easy to connect with the source and drain doped regions, which makes the formed semiconductor performance lower.

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