Semiconductor structure forming method

Abstract

The invention provides a semiconductor structure forming method, which comprises the steps of providing a semiconductor substrate, wherein the semiconductor substrate is provided with a pseudo gate structure; forming a dielectric layer for covering the semiconductor substrate and the sidewalls of the pseudo gate structure, wherein the surface of the dielectric layer is in flush with the top surface of the pseudo gate structure; removing the pseudo gate structure to form a groove; forming a high-k gate dielectric material layer on the sidewall and the bottom of the groove and the surface of the dielectric layer; forming an aluminum-titanium nucleating layer on the high-k gate dielectric material layer, wherein the content of titanium atoms in the aluminum-titanium nucleating layer is larger than that of aluminum atoms in the aluminum-titanium nucleating layer; forming an aluminum-titanium body layer on the aluminum-titanium nucleating layer, wherein the content of titanium atoms in the aluminum-titanium body layer is smaller than that of aluminum atoms in the aluminum-titanium body layer; forming a work function material layer by the aluminum-titanium nucleating layer and the aluminum-titanium body layer; forming a metal layer on the aluminum-titanium body layer, and fully filling the groove by the metal layer. The surface flatness of the work function material layer is improved.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for forming a semiconductor structure. Background technique [0002] With the continuous development of integrated circuit manufacturing technology, the feature size of MOS transistors is getting smaller and smaller. In order to reduce the parasitic capacitance of the gate of MOS transistors and improve the device speed, the gate stack of high K gate dielectric layer and metal gate structure is introduced into MOS transistors. In order to avoid the influence of the metal material of the metal gate on other structures of the transistor, the gate stack structure of the metal gate and the high-K gate dielectric layer is usually fabricated by a “gate last” process. [0003] In the prior art, the process of manufacturing a metal gate using a "gate last" process includes: providing a semiconductor substrate on which a replacement gate structure is formed, and the re...

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Problems solved by technology

[0006] However, the performance of the existing aluminum-titanium work function layer still needs to be improved

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