SiC Single Crystal Growth with Temperature-Staged Dislocation Reduction
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Solution Overview
Problem
Existing methods for manufacturing silicon carbide single crystals struggle to effectively reduce defects such as threading dislocations, which are inherent in the crystal growth process.
Innovation Solution
A method involving two steps: first, growing the silicon carbide single crystal while controlling the reaction vessel temperature to facilitate pair annihilation or synthesis of threading dislocations; second, maintaining the temperature to bring the leading ends of these dislocations close to the seed substrate surface through heat treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If crystal growth is performed using conventional HTCVD method, then silicon carbide single crystal can be obtained, but threading dislocations are generated in the crystal
Solution Approach 1:
The crystal growth process is divided into multiple distinct stages: initial crystal growth stage, intermediate stage with modified parameters, and final stage. Each stage has specific temperature and pressure conditions optimized for that phase, allowing progressive reduction of threading dislocations while maintaining crystal growth
Solution Approach 2:
The invention systematically changes growth parameters including temperature (2000-2500°C range), pressure conditions, and gas composition ratios during different stages of crystal growth. These parameter modifications control the formation and movement of threading dislocations, reducing their density in the final crystal
2Manufacturing precision
If heat treatment is performed to bring leading ends of threading dislocations close to surface, then defect density is reduced, but additional process time is required
Solution Approach 1:
The heat treatment step is incorporated as a preliminary or intermediate action within the overall crystal growth process rather than a separate post-processing step. By performing the heat treatment during the crystal growth sequence, the leading ends of threading dislocations are brought close to the surface before final crystal completion, reducing total process time
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 approach significantly reduces the density of threading dislocations by bringing their leading ends closer to the surface, thereby improving the quality of the silicon carbide single crystal ingot.
Implementation Method 1
heating the interior of the reaction vessel to a predetermined temperature, thereby growing a silicon carbide single crystal on the surface of the seed substrate
Implementation Method 2
perform pair annihilation of threading dislocations or synthesis of the threading dislocations
Implementation Method 3
growing a silicon carbide single crystal on the surface of the seed substrate
Implementation Method 4
maintaining the temperature inside the reaction vessel in the state of the first predetermined temperature after execution of the first step, to bring the leading ends of the threading dislocations close to the surface of the seed substrate
Data Source
AI summary
A method and an apparatus for manufacturing a silicon carbide single crystal, and a silicon carbide single crystal ingot, obtaining a silicon carbide single crystal reduced in defects such as threading dislocations, are provided. The method manufactures a silicon carbide single crystal by supplying a raw material gas into a reaction vessel with a seed substrate, and heats the interior to grow a silicon carbide single crystal on the surface of the seed substrate. The method includes growing the silicon carbide single crystal on the seed substrate surface, while controlling the temperature, to perform pair annihilation of threading dislocations or synthesis of the threading dislocations; and a second step of maintaining the temperature inside the reaction vessel in the state of the first predetermined temperature after execution of the first step, to bring the leading ends of the threading dislocations close to the surface of the seed substrate.