Silicon Vaporizer Layer Sequence for Corrosion Resistance
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Solution Overview
Problem
Existing vaporizer devices for inhalers, particularly those using silicon resistive heaters, face challenges with service life and reliability due to high operating temperatures and exposure to vaporized liquids, leading to contact pad degradation and corrosion, especially when using metals like aluminum and gold.
Innovation Solution
A layer sequence comprising a contact layer of aluminum, a diffusion barrier of titanium, an adhesive layer of nickel or titanium, and a connection layer of silver or gold is used to efficiently and stably connect the silicon vaporizer to electrical lines, preventing diffusion and corrosion, and ensuring reliable electrical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aluminum contact pads are used for electrical contacting of silicon vaporizer, then electrical connection is achieved, but corrosion occurs upon contact with vaporized liquids leading to failure
Solution Approach 1:
The patent applies a composite layer structure consisting of multiple materials: a first contact layer (aluminum or aluminum alloy) for electrical contact, a diffusion barrier layer (titanium or titanium alloy) to prevent interdiffusion, and a protective layer (silver, gold, or platinum) to prevent corrosion from vaporized liquids. This composite structure resolves the contradiction by combining the electrical conductivity of aluminum with the corrosion resistance of noble metals, while the diffusion barrier prevents degradation at the interfaces.
2Object-affected harmful factors
If gold contact pads are used for electrical contacting of silicon vaporizer, then corrosion resistance is improved, but silicon atoms diffuse through gold at elevated temperatures forming a vitreous layer that prevents electrical connection
Solution Approach 1:
The patent introduces a diffusion barrier layer (titanium or titanium alloy) as an intermediary between the silicon vaporizer and the gold contact layer. This intermediary layer prevents silicon atoms from diffusing through the gold at elevated temperatures, while allowing the gold to maintain its corrosion resistance properties. The diffusion barrier thus mediates between the conflicting requirements of corrosion protection and electrical conductivity.
3Stability of the object's composition
If bonding metals such as titanium or chromium are used for electrical contacting of silicon vaporizer, then stable interface is formed, but Schottky contact is created which is only conductive for one current direction
Solution Approach 1:
The patent segments the contact structure into multiple functional layers: a first contact layer for stable silicon interface (titanium or chromium), a diffusion barrier layer to prevent interdiffusion, and a second contact layer (aluminum or aluminum alloy) to provide ohmic contact for bidirectional current flow. This segmentation allows each layer to fulfill its specific function, resolving the contradiction between interface stability and electrical conductivity.
4Temperature
If conventional contact structures are used in high temperature operation up to 300°C, then vaporization function is achieved, but diffusion processes degrade the contact structure reducing service life
Solution Approach 1:
The patent employs a composite layer structure with a first contact layer, diffusion barrier layer, and protective layer that collectively resist thermal degradation at operating temperatures up to 300°C. The diffusion barrier layer specifically prevents thermally activated diffusion processes that would otherwise degrade the contact structure, while the protective layer prevents chemical degradation from vaporized liquids, thus maintaining reliability at high temperatures.
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 proposed layer sequence enhances the service life of the vaporizer device to at least 500 heating cycles at 300°C, maintains stability in the presence of vaporized liquids, and allows for efficient electrical connection, thereby improving system reliability and reducing production costs.
Implementation Method 1
a diffusion barrier comprising a titanium content; an adhesive layer comprising a nickel or titanium content
Implementation Method 2
a vaporizer, for vaporizing liquid supplied to the vaporizer, in the form of an electrical resistance heating element made of doped silicon
Data Source
AI summary
A vaporizer device for an inhaler, preferably for an electronic cigarette product or a medical inhaler, comprising:a vaporizer, for vaporizing liquid supplied to the vaporizer, in the form of an electrical resistance heating element made of doped silicon, andat least one electrical line connected to the vaporizer, whereinthe at least one electrical line is electrically connected to the vaporizer by a layer sequence, wherein the layer sequence comprises the following layers which, starting from the vaporizer, follow one another:a contact layer comprising an aluminum content, which is in contact with the vaporizer,a diffusion barrier comprising a titanium content,an adhesive layer comprising a nickel or titanium content, anda connection layer comprising, for example, a silver or gold content, via which the layer sequence is electrically connected to the at least one line.