Method for preparing metal silicide

Abstract

The invention discloses a method for preparing a metal silicide. The method comprises the steps of providing a semiconductor substrate, wherein the surface of the semiconductor substrate comprises at least one silicon conductive region; and implanting ions into the semiconductor substrate, wherein the implanted ions are carbon ions or silicon ions, and the temperature of the semiconductor substrate is not more than -50 DEG C in the ion implanting process; forming metal layers on the semiconductor substrate to cover the at least one silicon conductive region; performing a first annealing process on the semiconductor substrate; removing the metal layers which are not subjected to the annealing reaction with silicon materials in the at least one silicon conductive region; and performing a second annealing process on the semiconductor substrate, wherein the second annealing process is a millisecond annealing process. According to the method disclosed by the invention, the subsequently formed metal Ni can be prevented from spreading toward the inside of grooves, so that the junction leakage and the reduction of breakdown voltage are prevented.

Description

technical field [0001] The invention relates to a semiconductor device manufacturing process, in particular to a method for making metal silicide. Background technique [0002] In the existing MOS transistor technology, in order to improve the ohmic contact between the gate, source and drain of the transistor and the filling plug, metal silicide is usually formed on the surfaces of the gate, source and drain. At present, the metal silicide is mostly formed by using a self-aligned metal silicide (Silicidation) process. That is, after the source and drain are formed, a metal layer such as cobalt, titanium or nickel is formed to cover the source, drain and gate, and then one or more steps of rapid annealing (RTA) are used to make the metal layer and The silicon in the gate, source, and drain reacts to form a low-resistivity metal silicide, which lowers the sheet resistance of the source and drain. [0003] Figures 1A-1C It is a cross-sectional view of various steps in the pr...

AI Technical Summary

Problems solved by technology

However, in the above-mentioned one-step or multi-step annealing process, Ni is prone to isotropic diffusion, and part of Ni will diffuse into the substrate, especially into the channel, causing nickel corrosion.

The above-mentioned nickel corrosion will lead to an increase in leakage current and a decrease in source-drain breakdown voltage, which will affect the yield and life of semiconductor devices

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