Semiconductor device forming method

Abstract

The invention provides a semiconductor device forming method, which comprises the steps that: a substrate, a grid structure positioned on the substrate and side walls positioned at two sides of the grid structure are provided; an auxiliary side wall is formed on the surface of the side walls; a metal layer is formed on the surface of the auxiliary side wall and the exposed substrate; and the metal layer is subjected to annealing, metal silicide is formed in the substrate, the auxiliary side wall is used for preventing the metal layer from transversely diffusing into the side walls, and the formation of the metal silicide on the side walls is avoided. The semiconductor device forming method has the advantages that the auxiliary side wall is formed on the side walls, the gap of the metal silicide in the substrate positioned at two sides of the grid structure is enlarged, the electric leakage performance in an enhancement channel of the metal silicide formed through the metal diffusion is avoided, and the electric connection of a source / drain region and a grid electrode is further avoided, so the performance of a semiconductor device is improved.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for forming a semiconductor device. Background technique [0002] The self-aligned silicide technology is a process technology that reduces the resistance of the gate electrode and the source / drain region by forming a metal silicide layer on the gate electrode and the source / drain region. Nickel silicide layers and cobalt silicide layers are widely used as metal silicide layers. The Chinese patent application with the patent publication number CN101432860A provides a technical solution of using the nickel silicide layer as the metal silicide. [0003] The nickel silicide layer formed by nickel salicide technology may have different composition ratios. For example, the nickel silicide layer can be Ni 2 Si layer, NiSi layer or NiSi 2 any of the layers. Among them, the composition of different silicides is determined by the ratio of nickel to silicon in the r...

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Problems solved by technology

[0009] At the same time, if figure 2 As shown, the surface of the sidewall 030 also has part of the silicon dangling bonds, and the silicon dangling bonds will react with the nickel layer 040 to form nickel silicide on the surface of the sidewall 030, and the nickel silicide has The electrical conductivity will make the source / drain region in the substrate electrically connected to the gate 022, which will seriously affect the electrical conductivity of the semiconductor device

[0010] Further, as image 3 As shown, when removing the nickel layer on the surface of the substrate 001 and the surface of the sidewall 030, the nickel silicide on the sidewall 030 cannot be completely removed, resulting in a part of the nickel silicide remaining on the sidewall 030, The nickel silicide has electrical conductivity, which may further cause the source / drain region in the substrate 001 to be electrically connected to the gate 022, seriously affecting the electrical conductivity of the semiconductor device

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