Method for preparing films of cobalt silicate

Abstract

The method for preparing thin film of cobalt silicide includes steps: first, depositing Ti, Co, TiN in sequence on silicon base plate; next, carrying out short annealing in N2; then, carrying out selected etching in liquor tank of containing APM and SPM respectively; finally, carrying out second short annealing in N2. Thin film of cobalt silicide prepared by the disclosed method possesses advantages of less defect density on film, better heat stability, silicide and silicon matched to crystal lattice on substrate well so as to have more flattening interface, and reduced leakage current of PN junction.

Description

technical field [0001] The invention relates to the field of integrated circuit production and manufacturing, in particular to a method for preparing a cobalt silicide thin film. Background technique [0002] As the size of silicon unit devices continues to develop in the direction of deep submicron, polycrystalline CoSi 2 The phase transition of thin films on narrow polysilicon lines is not limited by the nucleation process, so it is widely used in VLSI manufacturing processes. Polycrystalline CoSi 2 When manufacturing VLSI, self-aligned CoSi can be formed on silicon wafers without photolithography on MOS devices. 2 Drain-source contact and gate electrode. As the size of CMOS devices continues to decrease in the horizontal and vertical directions, the shallow junction limits the thickness of the polycrystalline metal silicide film. When the film becomes thinner, the silicide or silicon interface is uneven and the thermal stability is poor, which seriously affects the PN ...

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Problems solved by technology

[0004] The preparation method of cobalt silicide thin film in the prior art adopts Co, Si direct reaction forms CoSi 2 Thin film, the film cannot withstand high temperature treatment above 900°C, and the thermal stability of the film is poor, so it is limited in the application of conventional CMOS technology

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