Semiconductor structures and methods of forming them

Abstract

The invention discloses a semiconductor structure and a formation method thereof. The formation method includes the following steps of: oxidizing a first work function layer after a sacrificial layeris formed on the first work function layer, and forming a diffusion barrier layer between the first work function layer and the sacrificial layer; forming metal grids on the diffusion barrier layer, wherein the metal grids, the diffusion barrier layer and the first work function layer are used for forming a grid structure. According to the technical scheme of the semiconductor structure and the formation method thereof, the diffusion barrier layer effectively prevents impurity ions of the metal grids from diffusing into the first work function layer, thereby the performance of the first work function layer is improved; after the sacrificial layer is formed, the first work function layer is oxidized to form the diffusion barrier layer, and the sacrificial layer can effectively control the flow rate of access reactants when the first work function layer is oxidized, thereby the thickness of the formed diffusion barrier layer can be effectively controlled, and the electrical properties ofthe semiconductor structure are improved.

Description

technical field [0001] The present invention relates to the technical field of semiconductor manufacturing, in particular to a semiconductor structure and a method for forming the same. Background technique [0002] The main semiconductor devices of integrated circuits, especially VLSIs, are metal-oxide-semiconductor field effect transistors (Metal-Oxide-Semiconductor, MOS). Traditional MOS transistors use oxynitride as the gate dielectric layer and polysilicon as the gate. [0003] With the development of semiconductor technology, the stacked gate structure in which oxynitride is used as the gate dielectric layer and polysilicon as the gate is difficult to meet the needs of small-scale semiconductor processes due to problems such as excessive leakage current and power consumption. Therefore, in the prior art, a metal gate using a metal material as a metal gate and a semiconductor device using a high dielectric constant dielectric material (High k) as a gate dielectric laye...

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Problems solved by technology

[0004] However, although the introduction of metal gates and high dielectric constant gate dielectric layers can improve the electrical properties of semiconductor structures to a certain extent, the electrical properties of semiconductor structures formed in the prior art still need to be improved.

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