SiC Single Crystal Growth via Surface Convection Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing SiC single crystals face challenges in achieving high-quality crystals due to convection and whirlpool issues in liquid phase growth, which affect crystal quality and limit the size of the crystals that can be produced.
Innovation Solution
The method involves actively controlling the flow of the raw material solution to align with the step developing direction on the crystal growth surface, allowing for the formation of macrosteps and subsequent conversion of defects, thereby smoothing the surface and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If convection control members are disposed in the liquid tub to suppress convection, then crystal quality is improved, but the space in the liquid tub is reduced making it difficult to produce large single crystals
Solution Approach 1:
The convection control function is extracted from the liquid tub environment and transferred to the crystal growth surface itself. By forming a convex portion on the crystal growth surface that acts as a convection control member, the solution flow is controlled at the interface rather than introducing separate control elements into the bulk liquid, thus maintaining crystal quality without reducing available growth space.
Solution Approach 2:
The convection control mechanism is moved from a three-dimensional space-filling element to a two-dimensional surface feature. The convex portion on the crystal growth surface controls convection patterns by modifying flow at the liquid-crystal interface, eliminating the need for volumetric convection control members that would occupy space within the liquid tub.
2Length of moving object
If the liquid tub is increased in size to accommodate larger crystals, then crystal size is improved, but the apparatus size increases
Solution Approach 1:
The crystal growth surface itself provides the convection control function through its convex portion, eliminating the need for separate convection control members. This self-service approach allows larger crystal growth areas without proportionally increasing apparatus complexity or size, as no additional control elements are required.
3Manufacturing precision
If raw material solution flow is completely eliminated to suppress convection, then crystal quality is improved, but crystal growth cannot proceed without forced flow
Solution Approach 1:
The flow control is applied locally at the crystal growth surface rather than globally throughout the entire liquid tub. The convex portion creates a localized flow pattern that suppresses detrimental convection near the growth interface while allowing bulk solution flow to continue, maintaining both crystal quality and growth productivity.
Solution Approach 2:
Instead of completely eliminating solution flow, the invention applies partial flow control only where necessary at the crystal growth surface. The convex portion modifies flow locally to suppress convection-induced defects while permitting sufficient bulk flow to deliver nutrients and maintain crystal growth rates.
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 enables the production of SiC single crystals with a smooth surface and a reduced number of defects, improving crystal quality and allowing for larger crystal growth without the need for complex apparatus modifications.
Implementation Method 1
when the raw material solution is allowed to flow in the same direction as a step developing direction, step bunching occurs on the crystal growth surface
Implementation Method 2
when the raw material solution is allowed to flow in a direction opposite to the step developing direction, step bunchings on the crystal growth surface are reduced and thus the step heights can be reduced, thereby smoothing the crystal growth surface
Implementation Method 3
growing a crystal from a seed crystal in a liquid phase (so-called a liquid phase growth method)
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Provided is a crystal producing apparatus capable of producing a single crystal having excellent quality. The crystal producing apparatus for growing a single crystal on a crystal growth surface of a seed crystal in a raw material solution by a liquid phase growth method, includes: a liquid tub (20) which accommodates a raw material solution (29); a crystal holding element (3) which holds a seed crystal (1); and a solution flowing element (25) which allows the raw material solution (29) in the liquid tub (20) to flow. Among these, the crystal holding element (3) is able to hold the seed crystal (1) in the liquid tub (20) and is movable in at least a partial region on an xy plane perpendicular to a z-axis that extends in a depth direction of the liquid tub (20).