Graphene-Plugged Porous Electrical Conductors for MEMS Switches
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Solution Overview
Problem
Traditional electrical conductors face issues with corrosion, diffusion, and friction due to porous surface layers, which affect signal integrity and usability, especially in applications like microelectromechanical systems (MEMS) switches.
Innovation Solution
A method involving a multi-layered electrical conductor structure with a substrate layer, a surface layer, and a graphene layer deposited within pores of the surface layer to plug them, using chemical vapor deposition (CVD) with organic compounds like methane to promote graphene growth, enhancing corrosion resistance and reducing friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a surface layer is deposited on the substrate layer to prevent corrosion, then corrosion resistance is improved, but the surface layer becomes porous which leads to oxidation and corrosion of the underlying surface
Solution Approach 1:
The patent applies the nesting principle by depositing a graphene layer within the pores of the surface layer, creating a nested structure where the graphene layer is embedded inside the porous surface layer. This nested configuration allows the graphene to plug the pores and prevent corrosion while maintaining the protective function of the surface layer.
Solution Approach 2:
The graphene layer acts as an intermediary substance that is deposited within the pores of the surface layer. This intermediary graphene layer plugs the pores and prevents direct contact between the corrosive environment and the underlying substrate, thereby resolving the contradiction between maintaining surface layer protection and preventing porosity-related corrosion.
2Reliability
If traditional plating methods are used to mitigate corrosion, then corrosion protection is improved, but the surface becomes porous resulting in oxidation and corrosion
Solution Approach 1:
The patent applies the nesting principle by depositing a graphene layer within the pores of the surface layer, creating a nested structure where the graphene is embedded inside the porous surface layer. This nested configuration allows the graphene to plug the pores and prevent corrosion while maintaining the protective function of the surface layer.
Solution Approach 2:
The patent applies parameter changes by utilizing the unique properties of graphene (its two-dimensional structure and ability to form dense barriers) to change the effective parameters of the surface layer. By introducing graphene with different physical and chemical parameters than traditional plating materials, the patent achieves pore plugging and corrosion prevention without compromising surface integrity.
3Reliability
If a surface layer is applied to protect the conductor, then corrosion resistance is improved, but friction, stiction and other contact forces increase
Solution Approach 1:
The patent applies composite materials by combining the surface layer with a graphene layer deposited within its pores. This composite structure integrates the corrosion protection of the surface layer with the low-friction properties of graphene, thereby reducing friction and stiction while maintaining corrosion resistance.
Solution Approach 2:
The patent applies local quality by having the graphene layer specifically located within the pores of the surface layer, providing localized friction reduction at the contact interfaces where it is most needed, while the surface layer maintains its overall protective function.
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 graphene layer effectively inhibits corrosion, reduces friction, and improves wear resistance, making the conductors suitable for applications where stiction is a concern, such as in MEMS switches.
Implementation Method 1
The publication "A Preliminary Investigation of Graphite, Graphene and Carbon Nanotubes as Solid State Lubricants" by Loyd et al. discloses the use of graphene as surface coating and lubricant on standard contact finishes.
Implementation Method 2
A need remains for an electrical conductor that addresses the aforementioned problems and other shortcomings associated with traditional electrical conductors.
Data Source
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AI summary
A method of manufacturing an electrical conductor (100) includes providing a substrate layer (102), depositing a surface layer (104) on the substrate layer that has pores (120) at least partially exposing the substrate layer, and forming graphene deposits (140) in the pores. Optionally, the graphene deposits may be formed only in the pores. The graphene deposits may be formed along the exposed portions of the substrate layer. The graphene layers may be selectively deposited or may be deposited to cover an entire layer. Optionally, the forming of the graphene deposits may include processing the electrical conductor using a chemical vapor deposition process using an organic compound precursor and heat of sufficient temperature to facilitate graphene growth on the metal compound comprising the substrate layer.