CVD Susceptor Positioning Element Thermal Insulation
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Solution Overview
Problem
In CVD reactors, the temperature difference between the susceptor and the positioning elements leads to uneven layer growth on substrates due to non-uniform thermal transfer, resulting in disparate growth rates at the edge and center of the substrate surfaces.
Innovation Solution
The introduction of a hollow space between the positioning element and the susceptor base, filled with a less thermally conductive substance, creates a thermal insulating barrier that homogenizes the temperature profile by reducing thermal conduction between the susceptor and the positioning elements, thereby minimizing temperature gradients across the substrate surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the positioning elements are in direct thermal contact with the susceptor base, then thermal conduction is enhanced, but temperature gradients form across the substrate surface leading to non-uniform layer growth
Solution Approach 1:
A hollow space filled with inert gas (argon or nitrogen) is introduced as an intermediary between the positioning element and the susceptor base. This gas-filled cavity acts as a thermal mediator that reduces direct thermal conduction from the susceptor to the positioning element, thereby minimizing temperature gradients across the substrate surface and achieving more uniform layer growth.
Solution Approach 2:
The thermal conductivity parameter of the interface between the positioning element and susceptor base is changed by replacing direct solid-to-solid contact with a gas-filled hollow space. The inert gas has lower thermal conductivity than the solid materials, thus reducing heat transfer and equalizing temperatures across the substrate.
2Temperature
If the hollow space is filled with a less thermally conductive substance, then thermal insulation is improved, but the complexity of the susceptor structure increases
Solution Approach 1:
The hollow space is designed to be automatically filled with inert gas from the CVD reactor atmosphere during operation. The positioning element structure itself serves as the container for the gas fill, eliminating the need for separate insulation components or complex assembly procedures. The gas fills the space naturally when the reactor is pressurized.
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
This solution ensures a more uniform temperature distribution across the substrate surface, enhancing layer growth consistency and reducing thermal disparities, thus improving the overall efficiency of the CVD process.
Implementation Method 1
The introduction of a hollow space between the positioning element and the susceptor base, filled with a less thermally conductive substance, creates a thermal insulating barrier that homogenizes the temperature profile by reducing thermal conduction between the susceptor and the positioning elements
Data Source
AI summary
A susceptor for a CVD-reactor includes insertion openings arranged in a bearing surface of the susceptor. An insertion section of a positioning element is inserted into one of the insertion openings. The insertion section forms positioning flanks with a section projecting from the insertion opening for fixing the position of a substrate. The insertion openings each have side walls and a base. The insertion section comprises bearing areas adjacent to the side walls of the insertion openings and a lower side of the positioning element facing the base of the insertion opening. The base of the insertion opening is separated from the lower side of the positioning element by a first distance. An edge protruding section of the positioning element is separated from a section of the bearing surface of the susceptor by a second distance.