Silane and borane treatments for titanium carbide films

Abstract

Methods of treating metal-containing thin films, such as films comprising titanium carbide, with a silane / borane agent are provided. In some embodiments a film comprising titanium carbide is deposited on a substrate by an atomic layer deposition (ALD) process. The process may include a plurality of deposition cycles involving alternating and sequential pulses of a first source chemical that comprises titanium and at least one halide ligand, a second source chemical comprising metal and carbon, wherein the metal and the carbon from the second source chemical are incorporated into the thin film, and a third source chemical, wherein the third source chemical is a silane or borane that at least partially reduces oxidized portions of the titanium carbide layer formed by the first and second source chemicals. In some embodiments treatment forms a capping layer on the metal carbide film.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates generally to processes for producing metal carbide thin films on a substrate by atomic layer deposition. In some embodiments, titanium carbide films produced by the atomic layer deposition (ALD) processes disclosed herein can be used in metal gate and metal electrode applications in metal oxide semiconductor field effect transistors (MOSFETs), such as n-channel MOSFETs (NMOS).[0003]2. Description of the Related Art[0004]Atomic layer deposition (ALD) is a generally self-limiting process, whereby alternated pulses of reaction precursors saturate a substrate surface and leave no more than about one monolayer of material per pulse. The deposition conditions and precursors are selected to provide self-saturating reactions, such that an adsorbed layer in one pulse leaves a surface termination that is non-reactive with the gas phase reactants of the same pulse. A subsequent pulse of different reac...

AI Technical Summary

Benefits of technology

This patent describes a method of using a silane / borane agent in atomic layer deposition (ALD) processes to create films containing metal carbide. The silane / borane agent can be used to reduce oxidized portions of metal films and to prevent further oxidation of the film itself or subsequent films. It can also help remove oxygen from deeper within a film. Overall, this method provides a way to create high-quality metal carbide films with reduced oxidation and improved quality.

Problems solved by technology

Despite the lower impurity levels in ALD films, the impurity content in ALD films can still be a problem.

In some cases, the semiconductor process flow necessarily limits the maximum deposition temperature such that that some residues are left in the film.

Halide impurities are present mainly at the interfaces, which can also lead to problems.

In another example, in some applications amorphous films are needed, which limits the growth temperature.

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