SiC Crystal Growth Doping via Carbon-Coated Dopant
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Solution Overview
Problem
The existing methods for growing semi-insulating SiC single crystal ingots face challenges such as non-uniform doping concentration with ingot thickness, excessive dopant sublimation, and quality deterioration due to thermal vibrations and impurities, especially as the ingot diameter increases, leading to complex and costly processes with poor control over doping and temperature gradients.
Innovation Solution
The process involves loading SiC and a dopant coated with a carbon-based material into a reaction vessel with a seed crystal, where the dopant is coated using a carbon-containing polymer resin, solvent, and SiC, and then solidifying the composition to grow the ingot, utilizing a porous body prepared through carbonization or graphitization to control doping and temperature uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a dopant is loaded into a porous graphite container or mixed with SiC powder, then doping can be achieved, but the process becomes complicated and costly, and doping concentration cannot be controlled due to impurities
Solution Approach 1:
The invention extracts the dopant from the porous graphite container and mixes it directly with SiC powder, eliminating the container and its associated impurities. This simplifies the process while maintaining precise doping concentration control.
Solution Approach 2:
The invention changes the physical state of the dopant from being contained in a porous structure to being mixed as powder, and controls the doping concentration by adjusting the mixing ratio rather than relying on container porosity.
2Manufacturing precision
If SiC and dopant are pulverized or used with large particle size, then doping can be achieved, but a separate thermal treatment step is required
Solution Approach 1:
The invention merges the doping process with the main SiC growth process by directly mixing the dopant with SiC powder before growth, eliminating the need for separate thermal treatment steps while ensuring uniform doping.
3Area of stationary object
If the reaction vessel size increases to accommodate larger diameter ingots, then larger ingots can be grown, but energy consumption increases and temperature gradient uniformity deteriorates
Solution Approach 1:
The invention uses local quality by having the dopant distributed throughout the SiC powder mixture, ensuring uniform doping concentration even in large diameter ingots without requiring excessive energy input or special temperature gradient control.
4Area of stationary object
If the reaction vessel size increases to accommodate larger diameter ingots, then larger ingots can be grown, but temperature gradient uniformity deteriorates leading to quality deterioration
Solution Approach 1:
The invention changes the approach to doping from using separate containers or powder mixing to direct incorporation of dopant with SiC powder, which maintains temperature gradient uniformity even in large diameter ingots by avoiding localized heat sources or sinks.
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 ensures uniform doping concentration, reduces unreacted raw materials, minimizes impurity mixing, and enhances the quality and shape of the SiC single crystal ingot, particularly for larger diameters, by maintaining a consistent temperature gradient and preventing dopant sublimation, thus improving the growth rate and polymorphism control.
Implementation Method 1
a dopant coated with a carbon-based material
Implementation Method 2
preventing dopant sublimation
Implementation Method 3
a porous body prepared through carbonization or graphitization of a SiC composition
Implementation Method 4
solidifying the composition to grow the ingot
Implementation Method 5
carbonization or graphitization
Implementation Method 6
maintaining a consistent temperature gradient
Data Source
AI summary
A method of growing a semi-insulating SiC single crystal ingot, the method comprising the steps of: (1) placing a dopant coated with silicon carbide (SiC) and a carbon-based material into a reaction vessel containing a seed crystal fixed thereto; and (2) growing a SiC single crystal on the seed crystal, thereby yielding a high-quality semi-insulating SiC single crystal ingot with a uniform thickness-based doping concentration. In addition, another embodiment relates to a method of growing a semi-insulating silicon carbide single crystal ingot, the method comprising the steps of: (a) placing in a reaction vessel, a composition comprising a carbon-containing polymer resin, a solvent, a dopant, and silicon carbide (SiC); (b) solidifying the composition; and (c) growing a SiC single crystal ingot on a seed crystal fixed to the reaction vessel, thereby yielding a high-quality semi-insulating SiC single crystal ingot with a uniform thickness-based doping concentration.