Segmented Shielding Member for SiC Crystal Growth
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Solution Overview
Problem
Large-diameter shielding members used in silicon carbide (SiC) single crystal growth inhibit the flow of SiC source gas, preventing homogeneous crystal growth due to radiation interference and temperature differences between the SiC source and growth surface.
Innovation Solution
A shielding member with multiple shielding plates, each covering 40% or less of the crystal growth container's base area, positioned between the SiC source and growth surface, with a shielding ratio of 0.5 or more, allowing efficient gas flow and temperature differentiation by varying plate heights and arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a large-diameter shielding member is used to prevent radiation interference, then the shielding effect is improved, but the flow of SiC source gas is inhibited
Solution Approach 1:
The shielding member is divided into multiple shielding plates arranged in an array rather than using a single large-diameter shielding member. This segmentation allows the SiC source gas to flow through the gaps between plates while still providing sufficient radiation shielding. The patent specifies that each shielding plate should have an area of 40% or less of the base area of the crystal growth container, and the shielding ratio (projection area of plates divided by internal circle area of source loading portion) should be 0.5 or more, optimizing both shielding effectiveness and gas flow.
2Temperature
If a large-diameter shielding member is used to block radiation, then the temperature difference between SiC source and growth surface is maintained, but the crystal growth homogeneity deteriorates
Solution Approach 1:
By dividing the shielding member into multiple smaller plates, the patent achieves both temperature control and homogeneous gas distribution. The segmented structure creates multiple flow paths for the SiC source gas, ensuring uniform supply across the growth surface while maintaining the necessary temperature difference through radiation blocking.
Solution Approach 2:
The shielding plates are arranged to create different local conditions - some areas have higher shielding density while others allow more gas flow. This local variation in shielding and flow characteristics ensures homogeneous crystal growth across the entire surface while maintaining overall temperature control.
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
Prevents radiation interference while ensuring even SiC source gas supply, promoting homogeneous crystal growth and preventing temperature unevenness, resulting in high-quality SiC ingots without polytype inclusions or cracks.
Implementation Method 1
a heating unit that is configured to heat the crystal growth container, and wherein the apparatus for single crystal growth grows a single crystal of the SiC source on a crystal installed on the crystal installation portion by sublimating the SiC source from the SiC source loading portion
Implementation Method 2
The radiation from the SiC source to the growth surface is prevented by the shielding member, and a difference in temperature occurs between the SiC source and the growth surface
Data Source
AI summary
A shielding member placed between a SiC source loading portion and a crystal installation portion in an apparatus for single crystal growth, including a crystal growth container including the loading portion which accommodates a SiC source in an inner bottom portion; a crystal installation portion facing the loading portion, and a heating unit configured to heat the crystal growth container. The device grows a single crystal of the SiC source on a crystal installed on the crystal installation portion by sublimating the SiC source from the loading portion. The shielding member includes a plurality of shielding plates, wherein each area of the plurality of shielding plates is 40% or less of a base area of the crystal growth container. When the SiC source loading portion is filled with a SiC source, a shielding ratio provided by a projection surface of the plurality of shielding plates is 0.5 or more.