Semiconductor structure and formation method thereof

Abstract

A semiconductor structure and a formation method thereof are disclosed. The formation method of the semiconductor structure comprises the following steps of providing a semiconductor substrate; forming fin portions on the semiconductor substrate; forming an isolation layer on the semiconductor substrate, wherein the surface of the isolation layer is lower than the top surface of each fin portion and covers a part of each fin portion; forming an epitaxial layer on each fin portion surface which is higher than the isolation layer; carrying out chemical dry method etching on the epitaxial layer so that roughness of an epitaxial layer surface is reduced. By using the method, flatness of the epitaxial layer surface can be increased and performance of a fin field effect transistor formed based on the above structure is improved.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a semiconductor structure and a forming method thereof. Background technique [0002] With the continuous development of semiconductor process technology, process nodes are gradually reduced, and gate-last (gate-last) process has been widely used to obtain an ideal threshold voltage and improve device performance. However, when the feature size of the device is further reduced, even if the gate-last process is adopted, the structure of the conventional MOS field effect transistor can no longer meet the requirements for device performance, and the fin field effect transistor (FinFET) has been obtained as a multi-gate device. Widespread concern. [0003] figure 1 A schematic diagram of a three-dimensional structure of a fin field effect transistor in the prior art is shown. [0004] Such as figure 1 As shown, it includes: a semiconductor substrate 10, on which a protrudi...

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Problems solved by technology

[0005] The fin field effect transistors in the prior art often suffer from gate leakage, and the performance of the fin field effect transistors needs to be further improved

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