Quartz Crucible Devitrification for Silicon Monocrystal Growth
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Solution Overview
Problem
Existing methods for pulling up silicon monocrystals using the Czochralski method face challenges in preventing dislocation during crystal growth, improving yield, and maintaining crystal quality over long periods, particularly due to issues with devitrification of the quartz crucible's inner wall surface, which requires costly and complex equipment setups and can lead to uneven coating and reduced productivity.
Innovation Solution
A method involving the application of a gel-like liquid containing a devitrification accelerator, such as barium carbonate, to the inner wall of the quartz crucible, which is made by mixing the accelerator with a thickening agent and solvent to create a viscous solution that can be applied uniformly at room temperature, eliminating the need for specialized equipment and ensuring stable and uniform devitrification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to prevent cristobalite formation on the quartz crucible inner wall, then dislocation occurrence is reduced, but equipment complexity and cost increase due to specialized coating equipment requirements
Solution Approach 1:
The invention changes the physical state of the devitrification accelerator from solid powder to gel-like liquid form, and applies it at room temperature instead of high temperature. This parameter change eliminates the need for specialized heating and coating equipment while achieving uniform devitrification of the quartz crucible inner wall, thus preventing cristobalite formation and dislocation without increasing equipment complexity
Solution Approach 2:
The gel-like liquid acts as an intermediary carrier that delivers the devitrification accelerator uniformly to the quartz crucible inner wall. This gel formulation allows room temperature application and ensures even distribution without requiring complex coating equipment, thereby maintaining crystal quality while simplifying the equipment needed
2Manufacturing precision
If devitrification accelerator is applied to the quartz crucible inner wall, then uniform devitrification is achieved, but application process becomes complex requiring specialized equipment
Solution Approach 1:
The invention transforms the devitrification accelerator into a gel-like liquid state and enables application at room temperature rather than high temperature. This parameter transformation allows simple, uniform application to the quartz crucible inner wall without requiring specialized coating equipment, achieving both uniform devitrification and equipment simplification
Solution Approach 2:
The gel-like liquid formulation enables the devitrification accelerator to self-adhere and distribute uniformly on the quartz crucible inner wall at room temperature. This self-service capability eliminates the need for external specialized coating equipment while ensuring uniform application and devitrification
3Reliability
If high temperature treatment is used to devitrify the quartz crucible, then cristobalite formation is prevented, but energy consumption increases and process time extends
Solution Approach 1:
The invention changes the application temperature parameter from high temperature to room temperature by using gel-like liquid formulation. This allows the devitrification accelerator to be applied and effective without high temperature treatment, thereby preventing cristobalite formation while significantly reducing energy consumption
Solution Approach 2:
The invention replaces the thermal field (high temperature treatment) with a chemical field (gel-like liquid application at room temperature). The devitrification accelerator in gel form chemically prevents cristobalite formation without requiring high temperature energy input, thus reducing energy consumption while maintaining effectiveness
4Productivity
If conventional devitrification methods are used, then crystal growth is maintained, but productivity decreases due to inability to reuse crucibles
Solution Approach 1:
The invention applies the devitrification accelerator in gel-like liquid form to the quartz crucible inner wall before use. This preliminary action creates a devitrified surface that prevents cristobalite formation during subsequent crystal growth, enabling crucible reuse without compromising crystal quality and thereby improving productivity
Solution Approach 2:
By changing the accelerator form to gel-like liquid and applying at room temperature, the invention creates a stable, adherent coating on the crucible inner wall. This parameter change enables the crucible to maintain its devitrified state through multiple uses, allowing reuse without crystal quality deterioration and thus enhancing productivity
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
This approach effectively prevents dislocation during crystal growth, enhances crystal quality, and improves productivity by allowing for the reuse of crucibles, reducing production costs and equipment investment while maintaining the durability of the quartz crucible.
Implementation Method 1
devitrifying (crystallizing) the inner wall surface of the quartz crucible safely, efficiently and uniformly during pulling up the silicon monocrystal
Implementation Method 2
mixing the accelerator with a thickening agent and solvent to create a viscous solution that can be applied uniformly
Data Source
AI summary
Provided is a method for pulling up and growing, by the Czochralski method, a silicon monocrystal from a melt obtained by fusing a silicon raw material for crystals within a quartz crucible. When the inner wall of the quartz crucible is made of a synthetic quartz layer, a gel-like liquid including a devitrification accelerator, a thickening agent, and a solvent is applied to the bottom surface of the quartz crucible inner wall or to both the bottom surface and the lateral surface thereof prior to filling the silicon raw material for crystals into the quartz crucible, whereas when the inner wall of the quartz crucible is made of a natural quartz layer, the gel-like liquid is applied to both the bottom surface and the lateral surface of the inner wall of the quartz crucible prior to filling the silicon raw material for crystals into the quartz crucible.