Movable Core Member for Silicon Carbide Ingot Stress Relief
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Solution Overview
Problem
Existing methods for producing large-diameter single-crystal silicon carbide ingots face challenges such as poor adhesive strength between the seed crystal and the holder, leading to defects like warpage and compressive stress, which limits the growth of high-quality ingots.
Innovation Solution
An apparatus with a crucible lid assembly that includes a movable core member and a seed crystal fixing unit, allowing for the relief of thermal and compressive stress by spacing the core member from the lid assembly and using a graphite core member to facilitate heat release, thereby reducing defects in ingot growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a seed crystal is attached to a holder using adhesive, then the seed crystal can be fixed during growth, but the adhesive strength is poor and fine pores form at the interface, limiting the growth of high-quality large-diameter silicon carbide single-crystal ingots
Solution Approach 1:
The invention removes the adhesive layer from the interface between the seed crystal and holder, extracting the harmful element that causes poor bonding and pore formation. The seed crystal is directly placed on the holder without adhesive, eliminating the source of interface defects while maintaining sufficient mechanical support during growth.
Solution Approach 2:
The invention introduces a graphite layer as an intermediary between the seed crystal and holder. This graphite intermediary provides thermal contact for heating while preventing direct adhesive bonding, serving as a mediator that enables both thermal transfer and mechanical support without the harmful adhesive layer.
2Stability of the object's composition
If the seed crystal is held firmly to prevent movement, then positioning stability is improved, but thermal and compressive stress cannot be relieved, causing warpage and defects in the ingot
Solution Approach 1:
The invention introduces a movable core member that can dynamically adjust its position within the growth chamber. This dynamic element allows the system to maintain positioning stability while providing stress relief through controlled movement, preventing warpage by accommodating thermal expansion and compressive stress during ingot growth.
Solution Approach 2:
The invention changes the physical parameters of the growth chamber by introducing a movable core member that can alter the volume and pressure conditions. This parameter change enables stress relief while maintaining stable positioning, as the core member's movement adjusts the internal environment to accommodate thermal and mechanical stresses without compromising ingot quality.
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 apparatus enables the production of large-diameter silicon carbide single-crystal ingots with fewer defects, achieving a surface density of 10000 ea/cm² or less and maintaining ingot quality by effectively managing thermal and mechanical stresses during growth.
Implementation Method 1
using a graphite core member to facilitate heat release
Implementation Method 2
relief of thermal and compressive stress by spacing the core member from the lid assembly
Data Source
Figure 1~2
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AI summary
An apparatus for producing an ingot includes a crucible body having an opening and in which raw materials are accommodated, and a lid assembly located at the opening and having a portion fixed to the crucible body. The lid assembly includes a placement hole having open upper and lower ends, a frame member arranged along a periphery of the opening while surrounding a periphery of the placement hole, and a core member located in the placement hole and movable upward and downward with respect to the frame member..