Susceptor Cover Plate Joint Layout for Uniform SiC Deposition
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Solution Overview
Problem
Existing devices for depositing SiC layers experience uneven layer thickness due to tensions in cover plates, leading to poor lateral layer thickness homogeneity, especially when thicker layers are deposited and the susceptor rotates.
Innovation Solution
The separation joint of the cover plates is angularly offset relative to a radial line by a certain angle, allowing the process gases to flow radially over the inner cover plates and substrates, improving layer thickness homogeneity. Additionally, the substrates can be rotationally driven about their center using a gas jet drive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the separation joints extend in the radial direction through the center of the susceptor and substrate, then the cover plates can be easily manufactured and assembled, but tensions cause the edges of the cover plates to rise leading to uneven layer thickness
Solution Approach 1:
The separation joints are positioned asymmetrically relative to the radial line through the substrate center. Specifically, the separation joints are offset angularly by 10-30 degrees from the radial direction, creating an asymmetric configuration that prevents uniform tension distribution and eliminates edge lifting, thereby maintaining layer thickness homogeneity while preserving ease of manufacture
Solution Approach 2:
The cover plate structure transitions from a uniformly symmetric design to one with locally differentiated joint positions. The separation joints are strategically placed at specific angular offsets in certain regions, creating local variations in the stress distribution pattern that prevent edge lifting while maintaining overall structural integrity and manufacturability
2Quantity of substance
If thicker layers are deposited on the substrates, then the deposition process can achieve higher material accumulation, but tensions in the cover plates increase causing edges to rise and layer thickness homogeneity to deteriorate
Solution Approach 1:
The asymmetric positioning of separation joints (offset by 10-30 degrees from radial lines) creates an uneven stress distribution pattern that accommodates thicker deposits. This asymmetric configuration prevents the uniform tension buildup that causes edge lifting during thick layer deposition, allowing higher material accumulation while maintaining lateral homogeneity
Solution Approach 2:
The joint configuration parameters are optimized for thick layer deposition scenarios. By positioning separation joints at specific angular offsets rather than radially, the structure adapts to handle increased material accumulation without developing the tension-induced edge lifting that plagues conventional radial joint designs
3Productivity
If the susceptor rotates about the center during deposition, then the deposition process can be enhanced, but the tensions in the cover plates cause edges to rise resulting in poor lateral layer thickness homogeneity
Solution Approach 1:
The asymmetric separation joint configuration (angularly offset by 10-30 degrees from radial lines) is specifically designed to work with rotating susceptors. This asymmetric arrangement creates a stress distribution pattern that remains stable during rotation, preventing edge lifting and maintaining layer thickness homogeneity while allowing the productivity benefits of susceptor rotation to be realized
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 results in better layer thickness homogeneity and allows for uniform deposition of SiC layers, even when thicker layers are deposited and the susceptor rotates.
Implementation Method 1
the substrates are heated to temperatures above 1000 degrees Celsius, preferably above 1300 degrees Celsius, with a heating device
Implementation Method 2
the substrates can be rotationally driven about their center using a gas jet drive
Implementation Method 3
gaseous starting materials containing silicon and carbon are fed into a process chamber of the CVD reactor
Data Source
AI summary
A device for depositing layers on flat substrates includes a susceptor which can be heated by a heating device. The substrates and cover plates enclosing same are arranged on an upper face of the susceptor facing a process chamber. The cover plates include inner cover plates, each of which forms an edge adjoining a substrate edge facing the center of the susceptor. The inner cover plates are arranged about the center of the susceptor in the circumferential direction, and adjacent ones of the inner cover plates adjoin each other at a separation joint. The separation joint is arranged at an angle α to a line which extends through the center of the susceptor and the center of one of the substrates in a radial direction.