Quartz Crucible Crystallization-Accelerator Layer
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Solution Overview
Problem
Conventional quartz glass crucibles deform under high temperatures during silicon single crystal pulling, leading to fluctuations in melt surface levels and oxygen concentration, and a gap between the crucible and carbon susceptor, affecting crystal diameter control.
Innovation Solution
A quartz glass crucible with a crystallization-accelerator-containing layer on its outer surface, where the concentration of the accelerator is between 1.0×10^13 and 4.8×10^15 atoms/cm^2, allowing for controlled crystallization and enhanced strength, reducing deformation and gap formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the crucible is heated to high temperature (1400°C or higher) for pulling-up process, then the silicon raw material can be melted and single crystal can be grown, but the crucible becomes low in viscosity and undergoes deformation such as sagging or collapse
Solution Approach 1:
A crystallization-accelerator-containing coating film is formed on the outer surface of the crucible body before the pulling-up process. This coating contains barium at a concentration of 1.0×10^13 to 4.8×10^15 atoms/cm², which accelerates crystallization of the crucible wall when heated, forming a protective crystalline layer that prevents deformation during high-temperature operation
Solution Approach 2:
The crucible structure combines quartz glass body material with a crystallization-accelerator-containing coating film. The coating film contains barium compounds that catalyze crystallization, creating a composite structure where the crystallized outer layer provides mechanical strength while the inner quartz glass maintains chemical inertness and melting function
2Strength
If a crystallization-accelerator-containing coating film with high barium concentration is formed on the crucible outer surface, then the crucible strength is enhanced, but the crystallization occurs too quickly causing a gap between the crucible and carbon susceptor
Solution Approach 1:
The barium concentration in the coating film is precisely controlled within the range of 1.0×10^13 to 4.8×10^15 atoms/cm². This parameter optimization ensures that crystallization occurs at an appropriate rate - fast enough to provide strength enhancement, but slow enough to allow the crucible to conform to the carbon susceptor shape before crystallization completes, eliminating gaps
3Productivity
If multi-pulling is performed to increase productivity, then more silicon single crystal ingots can be produced from one crucible, but the crucible undergoes cumulative deformation and damage
Solution Approach 1:
The crystallization-accelerator-containing coating film is applied in advance to the crucible outer surface. This preliminary coating ensures that when the crucible is subjected to repeated heating cycles for multi-pulling operations, the crystallization layer forms protectively during each cycle, preventing cumulative deformation and extending crucible service life
Solution Approach 2:
The coating film enables continuous crystallization protection throughout multiple pulling-up processes. The crystallization accelerator remains active across repeated heating cycles, maintaining crucible strength and shape stability throughout the entire multi-pulling operation sequence
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 crucible maintains stability during long-term single crystal pulling, ensuring consistent oxygen concentration and crystal diameter by eliminating the gap between the crucible and carbon susceptor, thus enabling efficient multi-pulling processes.
Implementation Method 1
a crystallization-accelerator-containing layer is formed on an outer surface of the crucible body... a concentration of a crystallization accelerator contained in the crystallization-accelerator-containing layer is 1.0×10^13 atoms/cm^2 or more and 4.8×10^15 atoms/cm^2 or less
Data Source
AI summary
A quartz glass crucible (1) includes: a crucible body (10) made of silica glass; and a crystallization-accelerator-containing layer (13) formed on an outer surface of the crucible body (10). A concentration of a crystallization accelerator contained in the crystallization-accelerator-containing layer (13) is 1.0×1013 atoms/cm2 or more and 4.8×1015 atoms/cm2 or less. The quarts glass crucible is intended to be capable of not only enduring a single crystal pulling-up process that takes a very long time, such as multi-pulling, but also stably controlling the oxygen concentration and crystal diameter of a silicon single crystal by eliminating a gap between the carbon susceptor and the crucible as much as possible.