Quartz Crucible Outer Layer for High-Temperature Pulling Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Quartz glass crucibles used in silicon single-crystal production face durability issues due to deformation during long-duration crystal pulling-up steps, particularly at high temperatures, necessitating improved crystallization and structural reinforcement.
Innovation Solution
A quartz glass crucible with a semi-molten layer featuring recesses, including through-holes, promotes crystallization on its outer surface, enhancing durability by forming a thick crystal layer, and a two-layer structure with a transparent and bubble-containing layer to withstand high temperatures and prevent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the temperature of the crucible increases during pull-up, then the viscosity of the glass decreases, but the crucible may be deformed during use
Solution Approach 1:
A semi-molten layer consisting of unmolten or semi-molten quartz powder is formed on the outer surface of the crucible before use. This preliminary layer serves as a protective barrier that promotes crystallization during heating, forming a thick crystal layer that strengthens the crucible wall and prevents deformation at high temperatures during the pull-up process.
Solution Approach 2:
The crucible employs a composite structure with an inner transparent glass layer and an outer layer containing a semi-molten quartz powder layer. This composite material approach combines the heat resistance of quartz glass with the structural reinforcement provided by the semi-molten layer that crystallizes during use, creating a multi-functional structure that resists thermal deformation.
2Strength
If a crystallization accelerator is applied onto or incorporated into a surface of a crucible, then glass is crystallized at a high temperature to increase the strength of the crucible, but further improvement of the durability is required
Solution Approach 1:
The invention changes the physical and chemical parameters of the outer surface by incorporating a semi-molten layer with specific characteristics (unmolten or semi-molten quartz powder with controlled particle size and composition). This layer undergoes controlled crystallization during heating, transforming from a semi-molten state to a crystalline structure that provides enhanced strength and durability, going beyond simple crystallization accelerator application.
3Reliability
If the thickness of the crystal layer is increased, then the durability of the crucible is improved, but the production process becomes more complex
Solution Approach 1:
The semi-molten layer on the crucible outer surface performs self-service by automatically crystallizing during the normal heating process of the pull-up operation. The crystallization occurs in-situ during use, forming the protective thick crystal layer without requiring separate crystallization treatment equipment or additional processing steps, thereby improving durability while avoiding production process complexity.
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 enhanced crucible design allows for long-duration crystal pulling-up, producing high-quality silicon single crystals with improved strength and resistance to deformation, reducing dislocation and pinhole formation.
Implementation Method 1
a semi-molten layer consisting of a fusion-bonded layer of unmolten or semi-molten quartz powder formed on an outer side of an outer surface of the crucible main body
Implementation Method 2
the outer side portion (outer layer) is formed of a bubble-containing layer including a number of bubbles in order to disperse the radiant heat from the outside to uniformly heat the inside of the crucible
Implementation Method 3
The inner side portion (inner layer) of the quartz glass crucible is formed of a transparent glass layer, which comes into contact with the silicon melt and thus contains substantially no bubbles
Data Source
AI summary
A quartz glass crucible includes a crucible main body consisting of silica glass, and a semi-molten layer consisting of a fusion-bonded layer of unmolten or semi-molten quartz powder formed on the outer side of an outer surface of the crucible main body. A number of recesses having a diameter of 0.2 mm or more and 5.0 mm or less and a depth of 50 μm or more are formed on a surface of the semi-molten layer. Some of the recesses are through-holes penetrating the semi-molten layer to reach an outer surface of the crucible main body, and the density of the through-holes is 1 through-hole/cm2 or more and 50 through-holes/cm2 or less.