Quartz Glass Crucible Inner Surface Crystallization
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Solution Overview
Problem
The generation of a brown ring on the inner surface of quartz glass crucibles during the pulling of single crystal silicon leads to crystallinity disorders in the silicon ingot, and existing solutions that use crystallization promoting agents introduce impurities into the silicon.
Innovation Solution
A method involving the production of a quartz glass crucible with a roughened inner surface, achieved by blast treatment using quartz powder, and subsequent heating to crystallize the surface, which suppresses the formation of a brown ring and crystallinity disorders without incorporating impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a crystallization promoting agent is added to the inner surface of the crucible to crystallize the surface, then the strength of the crucible is improved and brown ring generation is suppressed, but impurities from the agent are incorporated into the single crystal silicon, lowering its crystallinity
Solution Approach 1:
The invention uses a disposable sacrificial layer of amorphous quartz glass on the crucible inner surface that is intentionally designed to be consumed or transformed during the single crystal pulling process. This sacrificial layer prevents brown ring formation and impurity incorporation while maintaining crucible strength, as it is replaced by a crystallized surface during use.
Solution Approach 2:
The invention changes the physical and chemical parameters of the crucible inner surface by controlling the thickness, composition, and crystallization state of the inner layer. By adjusting these parameters, the surface can be optimized to prevent brown ring formation without introducing impurities, resolving the contradiction between strength and purity.
2Reliability
If the inner surface of the quartz glass crucible is roughened to promote crystallization, then brown ring generation is suppressed, but the manufacturing complexity increases
Solution Approach 1:
The invention applies preliminary action by pre-roughening the inner surface of the crucible before use, and pre-crystallizing the inner layer during manufacturing. These preliminary treatments ensure that the crucible is ready to prevent brown ring formation from the start of the single crystal pulling process, eliminating the need for complex in-process interventions.
Solution Approach 2:
The invention applies local quality by roughening only the specific region of the inner surface that contacts the silicon melt, and crystallizing only the inner layer in that region. This localized treatment reduces manufacturing complexity compared to treating the entire crucible, while still effectively preventing brown ring formation where it matters most.
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 method effectively prevents the generation of a brown ring and crystallinity disorders in single crystal silicon, resulting in high-quality silicon production by ensuring a crystallized roughened region on the crucible's inner surface.
Implementation Method 1
heating the quartz glass crucible having the roughened inner surface to crystallize a surface of the roughened region
Data Source
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Figure 3
AI summary
The present invention is a method for producing a quartz glass crucible for pulling a single crystal silicon from a silicon melt held therein, including the steps of: producing a quartz glass crucible having an outer layer including an opaque quartz glass containing bubbles therein and an inner layer including a transparent quartz glass containing substantially no bubbles; roughening a region of an inner surface of the produced quartz glass crucible, the region being in contact with the silicon melt when holding the silicon melt; and heating the quartz glass crucible having the roughened inner surface to crystallize a surface of the roughened region. This can produce a quartz glass crucible for pulling a single crystal silicon which can suppress generation of a brown ring on the inner surface of the crucible during pulling the single crystal silicon and can suppress crystallinity disorder of the single crystal silicon.