SiC Crystal Growth Filter with Layered Graphite Particle Traps
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Solution Overview
Problem
Conventional SiC crystal growth methods suffer from the deposition of silicon and carbon particles on the growing crystal surfaces, leading to defects due to the inclusion of these particles in the evaporated gas stream.
Innovation Solution
A SiC crystal growth apparatus and method that employs a filter with multiple layers of graphite plates, each with non-overlapping through holes forming a face-centered cubic structure, to remove particles from the gas stream before it reaches the seed, thereby preventing deposition on the crystal surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional PVT method is used without particle filtration, then the crystal growth process is simple and fast, but particles are deposited on the crystal surface causing defects and poor quality
Solution Approach 1:
A filter is introduced as an intermediary component between the source and seed to remove particles from the gas stream. The filter includes multiple layers with through-holes arranged in non-overlapping patterns, allowing gas molecules to pass while blocking larger particles that would otherwise deposit on the crystal surface and cause defects.
Solution Approach 2:
The filter utilizes a porous structure with controlled through-holes in multiple layers. The non-overlapping arrangement of through-holes creates a tortuous path that effectively traps particles while maintaining gas flow, demonstrating the application of porous material principles to solve the particle contamination problem.
2Reliability
If a filter with multiple layers and non-overlapping through holes is introduced, then particle removal efficiency is improved, but the apparatus complexity and manufacturing difficulty increase
Solution Approach 1:
The filter is segmented into multiple discrete layers, each with through-holes at specific positions. This segmentation allows for modular manufacturing where each layer can be fabricated separately and then assembled, reducing the overall manufacturing complexity while maintaining the non-overlapping through-hole configuration for effective particle removal.
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 apparatus effectively filters out particles, enhancing the quality of SiC crystals by preventing defects and ensuring higher purity.
Implementation Method 1
a filter configured to filter out particles from gas supplied from the source is provided between the seed and the source
Implementation Method 2
the filter includes a first layer, a second layer, and a third layer disposed in a direction from the source to the seed
Data Source
AI summary
Disclosed is a SiC crystal growth apparatus including a reaction cell provided in a vacuum furnace such that SiC crystals are grown in the reaction cell, the reaction cell is configured such that a source is disposed in a lower region of an area defined by a crucible and a cover and a seed is provided below the cover, and a filter configured to filter out particles from gas supplied from the source is provided between the seed and the source, the filter includes a first layer, a second layer, and a third layer disposed in a direction from the source to the seed and spaced apart from each other, first through holes, second through holes, and third through holes are formed through the first layer, the second layer, and the third layer, respectively, and centers of the first to third holes form a face-centered cubic structure.