Semiconductor structure and formation method thereof

Abstract

The invention relates to a semiconductor structure and a formation method thereof. The formation method comprises the steps of providing a substrate; forming an interlayer dielectric layer on the substrate; forming an opening exposing the substrate in the interlayer dielectric layer; forming a gate dielectric layer at the bottom and side wall of the opening; performing a film forming process for at least one time through an atomic layer deposition process, and forming an aluminum-containing work function layer on the gate dielectric layer, wherein the pulse number of an aluminum-containing precursor in the film forming process is at least 2 when the number of times of the film forming process is 1, and the pulse number of the aluminum-containing precursor in the at least one time of the film forming process is at least 2 when the number of times of the film forming process is greater than 1; and forming a metal gate in the opening in which the work function layer is formed. The contentof aluminum atoms in the opening is increased through increasing the pulse number of the aluminum-containing precursor, especially the pulse number in the first time of the film forming process, andthe deposition ability of the aluminum atoms in the opening is improved, thereby increasing the aluminum atom content of the work function layer, and thus improving a problem of threshold voltage flipof transistors.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a semiconductor structure and a forming method thereof. Background technique [0002] The main semiconductor device of an integrated circuit, especially a very large scale integrated circuit, is a metal-oxide-semiconductor field effect transistor (MOS transistor). With the continuous development of integrated circuit manufacturing technology, the technology nodes of semiconductor devices continue to decrease, and the geometric dimensions of semiconductor devices follow Moore's law. When the size of semiconductor devices is reduced to a certain extent, various secondary effects caused by the physical limits of semiconductor devices appear one after another, and it becomes more and more difficult to scale down the feature size of semiconductor devices. Among them, in the field of semiconductor manufacturing, the most challenging thing is how to solve the problem of large...

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Problems solved by technology

[0005] In the prior art, the adjustment of the threshold voltage of the transistor is realized by forming a work function layer in the gate structure of the transistor, but the transistor with the work function layer still has the problem of poor electrical performance, resulting in poor performance of the formed semiconductor structure

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