SiC PVT Crucible Segmentation for Simultaneous Crystal Growth
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Solution Overview
Problem
Current physical vapor transport (PVT) growth systems for silicon carbide (SiC) crystals are limited by slow growth rates and high costs due to inefficient temperature distribution and excessive use of expensive materials, and existing methods for growing multiple crystals simultaneously either result in defects or increased costs.
Innovation Solution
A PVT growth system with a crucible divided into a central source material compartment and two symmetric growth compartments, each separated by a gas permeable porous membrane, maintaining symmetry and reducing diffusion resistance through optimized membrane design, allowing for simultaneous growth of two SiC crystals with a uniform temperature profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional PVT growth systems are used to grow SiC single crystals, then defect-free quality is maintained, but the growth rate is slow (around 100 μm/h)
Solution Approach 1:
The crucible is divided into multiple growth compartments (first and second compartments) that can simultaneously grow multiple SiC single crystals. This segmentation allows parallel production, increasing overall productivity while maintaining the defect-free quality characteristic of conventional PVT growth.
2Productivity
If multiple SiC single crystals are grown simultaneously in a common crucible without partitioning, then productivity increases, but temperature distribution becomes inefficient and defects occur
Solution Approach 1:
The crucible is divided into multiple growth compartments separated by partitions, allowing multiple crystals to grow simultaneously while maintaining proper temperature distribution in each compartment, thus preventing defects and ensuring crystal quality.
Solution Approach 2:
Each growth compartment is equipped with its own heat dissipation channel and thermal insulation structure, allowing localized temperature control optimized for each crystal growth zone, ensuring uniform temperature distribution and preventing defects in each individual crystal.
3Manufacturing precision
If expensive highly pure crucible materials are used to grow multiple crystals simultaneously, then crystal quality is maintained, but costs significantly increase
Solution Approach 1:
The crucible is segmented into multiple compartments using partitions, allowing multiple crystals to be grown in a single crucible without requiring multiple expensive crucibles, thus reducing material costs while maintaining crystal quality.
Solution Approach 2:
A single crucible structure serves multiple functions by simultaneously growing multiple SiC single crystals in separate compartments, maximizing the utilization of the crucible and reducing the need for additional expensive materials.
4Productivity
If the crucible diameter is enlarged to grow multiple crystals simultaneously, then productivity increases, but costs for source material and apparatus geometry increase
Solution Approach 1:
The crucible is divided into vertical compartments that grow multiple crystals simultaneously within the same crucible diameter, avoiding the need to enlarge the crucible while still achieving increased productivity through parallel growth.
Solution Approach 2:
Instead of increasing crucible diameter horizontally to grow more crystals, the invention utilizes the vertical dimension by creating multiple stacked compartments, allowing simultaneous growth of multiple crystals without increasing the crucible's footprint or source material requirements.
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 system achieves a faster growth rate for SiC crystals while maintaining defect-free quality and reducing costs by maintaining symmetry and minimizing the use of expensive materials, with the ability to grow two crystals simultaneously without increasing the crucible or source material requirements.
Implementation Method 1
a source material compartment for containing a SiC source material, wherein said source material compartment is arranged symmetrically between said growth compartments and is separated from each of the growth compartments by a gas permeable porous membrane
Implementation Method 2
Physical vapor transport (PVT) is essentially a sublimation and re-condensation process, in which a source material and a seed crystal are placed inside a growth furnace in such a way that the temperature of the source material is higher than that of the seed, so that the source material sublimes and the vapor species diffuse and deposit onto the seed to form single crystals
Implementation Method 3
A thermal insulation material 208 surrounds the crucible 202 and is only open in the region of a heat dissipation channel 110 which generates the temperature gradient which is necessary for re-condensation
Data Source
AI summary
The present invention relates to a configuration and in particular a physical vapor transport growth system for simultaneously growing more than one silicon carbide (SiC) bulk crystal. Furthermore, the invention relates to a method for producing such a bulk SiC crystal. A physical vapor transport growth system for simultaneously growing more than one SiC single crystal boule comprises a crucible containing two growth compartments for arranging at least one SiC seed crystal in each of them, and a source material compartment for containing a SiC source material, wherein said source material compartment is arranged symmetrically between said growth compartments and is separated from each of the growth compartments by a gas permeable porous membrane.