Porous Substrate Interface Structure for High-Loading CVD
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Solution Overview
Problem
Thermal processes like chemical vapor deposition (CVD) are limited by the surface area of the substrate exposed to process gases, leading to inefficient loading of product solids and potential plugging or fouling of the substrate.
Innovation Solution
The use of substrate interface structures with porous walls made of high-temperature materials like carbon fiber or ceramics, which maintain gas flow and evenly distribute process gases around the substrate, reducing the risk of plugging and enabling higher loading of product solids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the substrate surface area is increased to improve product solid loading, then the deposition capacity increases, but the risk of gas flow blockage and substrate plugging increases
Solution Approach 1:
The substrate is designed with a porous structure that allows process gases to penetrate through to the interior surfaces. This porous configuration enables increased surface area exposure to gases without creating blockages, as the open pore structure maintains gas flow pathways even as product solids deposit on the substrate surfaces.
Solution Approach 2:
The invention transitions from a conventional two-dimensional substrate surface to a three-dimensional porous structure. This dimensional change provides additional interior surfaces that are accessible to process gases through the porous walls, effectively increasing the reactive surface area without compromising gas flow access.
2Productivity
If the substrate is exposed to higher concentrations of process gases to improve deposition rate, then the productivity increases, but the risk of localized overheating and uneven deposition increases
Solution Approach 1:
The porous substrate structure segments the gas flow into multiple pathways distributed across numerous pores. This segmentation prevents localized concentration buildup and promotes uniform distribution of process gases across the substrate surface, enabling higher overall deposition rates while maintaining uniformity.
Solution Approach 2:
The porous structure creates locally optimized zones for gas flow and deposition. Different regions of the porous substrate have controlled permeability and surface area that are optimized for their specific locations, ensuring uniform deposition characteristics even when exposed to high concentrations of process gases.
3Productivity
If the substrate interface structure has high surface area to maximize gas contact, then the deposition efficiency increases, but the amount of solid product deposited on the interface structure itself increases causing fouling
Solution Approach 1:
The substrate is extracted from direct contact with the process gases by placing it within the porous interface structure. The gases must pass through the porous walls to reach the substrate, which filters and distributes the gases uniformly while preventing direct fouling of the substrate surface and the interface structure.
Solution Approach 2:
The porous interface structure acts as an intermediary between the process gases and the substrate. It mediates the gas flow by distributing gases uniformly across the substrate while preventing direct deposition on the interface structure itself, thereby reducing fouling while maintaining high deposition efficiency.
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 substrate interface structures enhance the exposure of the substrate to process gases, allowing for more efficient deposition of product solids without blocking access, thus improving the loading capacity and reducing maintenance.
Implementation Method 1
The porous walls enable process gases to flow into substrate without becoming blocked, such that a greater amount of the substrate may be exposed to process gases
Implementation Method 2
The substrate interface structure has porous walls formed from materials having high thermal stability, such as carbon fiber or ceramics
Implementation Method 3
Thermal processes, such as vapor-phase reactions, may involve chemical vapor deposition of a solid product onto a substrate
Implementation Method 4
In methane pyrolysis, methane breaks down at high temperatures to form solid carbon that deposits onto surfaces of the substrate
Data Source
AI summary
An apparatus for a chemical vapor deposition (CVD) process includes a substrate interface structure. The substrate interface structure includes a high temperature material that is thermally stable at 400 degrees Celsius (° C.), such as a carbon fiber or a ceramic. The substrate interface structure defines an inner volume configured to house a substrate. The substrate interface structure is configured to position within a retort chamber and maintain flow of a process gas around an outer radial surface of the porous wall.