Epitaxial Susceptor with Cylindrical Portion for Uniform Heating
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Solution Overview
Problem
The uniformity of temperature in the susceptor of epitaxial deposition reactors is not achieved due to the non-uniform electromagnetic field generated by flat inductors, leading to non-uniform heating, which results in defects and stress in deposited layers on substrates.
Innovation Solution
A susceptor design comprising a disc-shaped portion for substrate support and a cylindrical or conical portion for enhanced heating, where the disc-shaped portion is heated by a first inductor and the cylindrical or conical portion indirectly heats the central zone through conduction, ensuring uniform temperature distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a flat inductor is used to heat the susceptor through electromagnetic induction, then the susceptor can be heated efficiently, but the temperature distribution becomes non-uniform with the central zone being cooler
Solution Approach 1:
The susceptor is divided into two functional portions: a disc-shaped portion for substrate support and a cylindrical or conical portion for enhanced heating. This segmentation allows different regions to serve different purposes, with the cylindrical portion specifically designed to address the non-uniform heating issue by being heated by a second inductor and conducting heat to the central zone of the disc-shaped portion.
Solution Approach 2:
Different portions of the susceptor are given different properties and functions. The disc-shaped portion has good thermal conductivity for heat distribution, while the cylindrical or conical portion is specifically designed to be heated by electromagnetic induction and act as a heat source for the central zone. This local differentiation solves the temperature uniformity problem.
2Temperature
If the susceptor is made of graphite for good heat conduction, then heat distributes well across the surface, but the central zone still remains cooler due to weak electromagnetic field at the axis
Solution Approach 1:
The cylindrical or conical portion acts as an intermediary heat transfer element. It is directly heated by the second inductor through electromagnetic induction and then conducts this heat to the central zone of the disc-shaped portion, effectively mediating the heat transfer to the area where the electromagnetic field is weakest.
Solution Approach 2:
The solution moves from a two-dimensional flat heating approach to a three-dimensional structure by adding the cylindrical or conical portion. This vertical dimension allows the second inductor to heat the cylindrical portion, which then conducts heat radially outward to the central zone, solving the field strength limitation.
3Manufacturing precision
If a single substrate is supported on the susceptor, then the substrate receives heat, but temperature non-uniformity causes defects and stress in the deposited layer
Solution Approach 1:
The susceptor is segmented into functional zones that work together to provide uniform heating. The disc-shaped portion supports the substrate while the cylindrical or conical portion provides additional heating to the central zone, ensuring temperature uniformity across the entire substrate surface for high-quality deposition.
Solution Approach 2:
The invention changes the physical parameters of the susceptor by adding a cylindrical or conical portion with different geometric properties. This structural parameter change enables differential heating zones that compensate for the non-uniform electromagnetic field, achieving uniform temperature distribution for defect-free deposition.
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 configuration allows for uniform heating of the susceptor, improving the quality of deposited layers by maintaining consistent temperature across the substrate, reducing defects and stress, and enhancing the control over temperature profiles.
Implementation Method 1
the heating of the susceptor can be obtained through a first inductor adapted to directly heat (in particular by induction) the disc-shaped portion
Implementation Method 2
a second inductor adapted to directly heat (in particular by induction) the cylindrical or conical portion
Implementation Method 3
and to indirectly heat (in particular by conduction) the disc-shaped portion, in particular its central zone
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
The present invention concerns a susceptor comprising a disc-shaped portion (21) and a cylindrical or conical portion (22); the disc-shaped portion (21) is used to (directly or indirectly) support one or more substrates to be subjected to epitaxial deposition inside a reaction chamber of an epitaxial deposition reactor; the cylindrical or conical portion (22) is used to contribute to the heating of the disc-shaped portion (21); thanks to the configuration of the susceptor, it is possible to heat the disc-shaped portion (21) to a very uniform temperature; in fact, for example, the heating of the susceptor can be obtained through a first inductor (4) adapted to directly heat the disc-shaped portion (21), in particular its outer annular zone, and a second inductor (5) adapted to directly heat the cylindrical or conical portion (22) and indirectly heat the disc-shaped portion (21), in particular its central zone.