Silicon Carbide Ion Source Liners for Fluorine Corrosion Resistance
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Solution Overview
Problem
Conventional ion source chamber materials, such as refractory metals and graphite, are prone to corrosion when exposed to fluorine-based or oxygen-based compounds, leading to shortened lifetimes and impurity introduction during ion implantation, which affects device performance and yield.
Innovation Solution
The ion source chamber components are replaced with silicon carbide (SiC) materials, specifically non-stoichiometric sintered SiCx with a carbon to silicon molar ratio between 1.1 and 1.45, providing improved corrosion resistance and reduced volatile compound generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional refractory metals and graphite are used in ion source chamber components, then the components can be manufactured with standard materials, but the components are prone to corrosion when exposed to fluorine-based or oxygen-based compounds, leading to shortened lifetimes and impurity introduction
Solution Approach 1:
The patent applies composite materials by combining silicon carbide (a ceramic material) with traditional metal components in the ion source chamber. Specifically, silicon carbide liners are installed within the metal chamber, and silicon carbide inserts are placed in critical areas exposed to corrosive compounds. This composite approach allows the system to leverage the corrosion resistance of silicon carbide while maintaining the structural integrity and electrical conductivity of metal components, thereby resolving the contradiction between reliability and corrosion resistance.
Solution Approach 2:
The patent creates a protective environment by using silicon carbide materials that are chemically inert to fluorine-based and oxygen-based compounds. The silicon carbide liners and inserts form a barrier that prevents direct contact between the corrosive compounds and the metal components, effectively creating a chemically inert environment within the ion source chamber. This inert environment protects the metal components from corrosion while allowing them to function normally.
2Object-generated harmful factors
If conventional refractory metals are used in ion source chamber components, then the components provide necessary structural strength, but they generate volatile compounds when exposed to fluorine-based or oxygen-based compounds, contaminating the substrate
Solution Approach 1:
The patent uses composite materials where silicon carbide liners and inserts are combined with metal components. The silicon carbide portions prevent the generation of volatile metal compounds by acting as a physical barrier, while the metal portions maintain the necessary structural strength. This composite structure eliminates impurity generation from metal corrosion while preserving mechanical integrity.
Solution Approach 2:
The silicon carbide liners and inserts serve as intermediary materials between the corrosive fluorine-based or oxygen-based compounds and the metal components. This intermediary layer prevents direct interaction between the compounds and metals, stopping the formation of volatile metal compounds that would contaminate the substrate, while still allowing the metal components to provide structural support.
3Reliability
If silicon carbide components are used in ion source chamber, then corrosion resistance and operating lifetime are improved, but the device complexity increases due to material replacement
Solution Approach 1:
The patent applies local quality by using silicon carbide materials only in specific locations where corrosion resistance is most critical, rather than replacing all components. The silicon carbide liners line the interior surfaces exposed to corrosive compounds, and inserts are placed in high-risk areas. This localized approach provides maximum protection where needed while minimizing the overall complexity increase and cost of the system.
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 use of silicon carbide components enhances the operating lifetime of ion source chamber components, reduces impurity introduction, and maintains device performance by minimizing the generation of volatile compounds that can contaminate the substrate.
Implementation Method 1
silicon carbide (SiC) materials, specifically non-stoichiometric sintered SiCx with a carbon to silicon molar ratio between 1.1 and 1.45, providing improved corrosion resistance
Implementation Method 2
an inlet aperture for introducing a gas to be ionized into plasma and an exit aperture opening through which the plasma is extracted to form the ion beam
Data Source
AI summary
An ion source chamber for ion implantation system includes a housing that at least partially bounds an ionization region through which high energy electrons move from a cathode to ionize gas molecules injected into an interior of the housing; a liner section defining one or more interior walls of the housing interior, wherein each liner section includes a interiorly facing surface exposed to the ionization region during operation the ion implantation system; a cathode shield disposed about the cathode; a repeller spaced apart from the cathode; a plate including a source aperture for discharging ions from the ion source chamber; wherein at least one of the repeller, the liner section, the cathode shield; the plate, or an insert in the plate defining the source aperture comprise silicon carbide, wherein the silicon carbide is a non-stoichiometric sintered material having excess carbon.