Silane Borane Treatment for Titanium Carbide Film Oxidation
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Solution Overview
Problem
Atomic layer deposition (ALD) processes for metal carbide thin films often result in high impurity levels, particularly halide residues, which can lead to oxidation issues and shifts in workfunction, especially in low-temperature deposition of transition metal nitrides and carbides, limiting their application in integrated circuits.
Innovation Solution
The use of silane or borane agents in ALD processes to reduce oxidation of metal carbide films, forming a capping layer that prevents further oxidation and acts as a barrier for subsequent layers, thereby controlling impurity levels and maintaining the integrity of the metal carbide films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If low temperature deposition is used for transition metal nitrides and carbides, then amorphous films are obtained, but impurity content exceeds acceptable limits
Solution Approach 1:
The patent changes the chemical parameters of the deposition process by using silane or borane agents during ALD cycles. These agents react with halide residues and oxygen contaminants, transforming the chemical composition of the film while maintaining low deposition temperatures that produce amorphous structures. This resolves the contradiction by allowing amorphous film formation without accumulating unacceptable impurity levels.
2Temperature
If halide-containing precursors are used in ALD processes, then deposition can proceed at lower temperatures, but halide residues remain in the film
Solution Approach 1:
The patent extracts harmful halide residues from the film through chemical reactions with silane or borane agents. These agents selectively react with halide species during or after deposition cycles, removing them from the film structure. This allows the use of low-temperature deposition with halide precursors while eliminating the resulting halide residues that would otherwise contaminate the film.
Solution Approach 2:
Silane or borane agents serve as intermediary substances that mediate between the halide-containing precursors and the final film structure. These intermediaries react with halide residues to form volatile byproducts that can be removed, thereby enabling low-temperature deposition with halide precursors without retaining harmful halide contaminants in the final film.
3Reliability
If metal carbide films are deposited without protection, then oxidation occurs leading to workfunction shifts, but additional protection layers increase process complexity
Solution Approach 1:
The patent merges the deposition process with protection functionality by incorporating silane or borane agent treatment into the ALD cycles themselves. Rather than adding separate protection layers, the treatment is integrated into the deposition process, allowing the metal carbide film to acquire oxidation resistance during deposition. This reduces overall process complexity while maintaining workfunction stability.
Solution Approach 2:
The metal carbide film undergoes self-protection through in-situ treatment with silane or borane agents during the deposition process. The film acquires its own oxidation resistance without requiring external protection layers, as the treatment agents react with oxygen contaminants and form protective surface terminations directly on the film during deposition. This eliminates the need for additional protection steps.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The silane or borane treatment effectively reduces oxidation, limits impurity incorporation, and maintains the electrical properties of metal carbide films, enhancing their suitability for applications in semiconductor devices by reducing resistivity and oxidation resistance.
Implementation Method 1
The silane/borane agent may form a barrier to at least partially prevent further oxidation of the film itself or of films subsequently deposited over the treated film
Implementation Method 2
an organosilane, organoborane, silane, or borane (generally referred to herein as a 'silane/borane agent') is utilized in atomic layer deposition (ALD) processes for depositing a boron- or silicon-containing film comprising metal carbide
Implementation Method 3
The silane/borane agent may serve to reduce oxidized portions of a metal film
Implementation Method 4
The silane/borane agent may form a barrier to at least partially prevent further oxidation of the film
Data Source
AI summary
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.