Preparation method of high-k metal gate structure

Abstract

The invention provides a preparation method of a high-K metal gate structure. The method at least comprises the following steps that: a substrate is provided and an interface layer and a high-K dielectric layer are successively formed on the substrate from bottom to top; a blocking layer is deposited on the high-K dielectric layer; a silicon layer is deposited on the blocking layer by using a chemical vapor deposition method, so that the silicon atom or silicon iron enters the blocking layer to form a silicon-doped blocking layer; and a metal gate layer is manufactured. According to the method provided by the invention, the subsequent rapid high-temperature heat treatment is not needed, thereby solving problems of high-K medium layer crystallization and interface layer thickening; the process is simplified; and the silicon-doped blocking layer is used as the metal diffusion blocking layer, thereby effectively preventing the metal in the metal gate layer from being diffused in the high K medium and maintaining the good performance of the device.

Description

technical field [0001] The invention belongs to the field of semiconductor manufacturing, and relates to a preparation method of a gate structure, in particular to a preparation method of a high-K metal gate structure. Background technique [0002] In the traditional MOS transistor process, SiO is usually used 2 As the gate dielectric, heavily doped polysilicon is used as the gate electrode material, but as the feature size continues to shrink, SiO in MOS transistors 2 The gate dielectric is approaching its limit. For example, in a 65nm process, SiO 2 The thickness of the gate has been reduced to 1.2 nanometers, which is about 5 silicon atomic layers thick. If it continues to shrink, the leakage current and power consumption will increase sharply. At the same time, problems such as the diffusion of doped boron atoms caused by the polysilicon gate electrode, the depletion effect of polysilicon, and the excessively high gate resistance will become more and more serious. Th...

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Problems solved by technology

[0006] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a method for preparing a high-K metal gate structure, which is used to solve the problem of metal diffusion in the metal gate layer in the prior art and the high-temperature heat treatment that causes The high-K dielectric layer crystallizes and re-grows the interface layer, which thickens the interface layer and adversely affects the device

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