Monocrystalline Silicon Production via Free-Floating Melt and Coated Reactor
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Solution Overview
Problem
The production of monocrystalline silicon is energy-intensive and involves complex, multi-stage processes that can introduce contamination and inefficiencies, particularly when converting polycrystalline silicon to monocrystalline form.
Innovation Solution
A method involving a 'free-floating melt' process where semiconductor material is fed into a heating zone in liquid form, stabilized by a seed crystal, and solidified through a controlled solidification front, with the use of a gas stream for thermal decomposition and a reactor vessel coated with solidified semiconductor material to prevent contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional multi-stage purification processes are used to produce high-purity silicon, then purity is improved, but energy consumption and process complexity increase
Solution Approach 1:
The reactor vessel is pre-coated with solidified semiconductor material (silicon) before the main production process. This preliminary coating creates a contamination-free surface that prevents crucible wall contamination from the start, eliminating the need for complex multi-stage purification processes and significantly reducing energy consumption while maintaining high purity
Solution Approach 2:
The solidified semiconductor material coating acts as an intermediary layer between the crucible wall and the liquid semiconductor material. This intermediate layer prevents direct contact and potential contamination, allowing the production of high-purity monocrystalline silicon through a simplified single-stage process
2Reliability
If conventional crucible-based melting processes are used, then liquid semiconductor material is contained, but contamination from crucible walls occurs
Solution Approach 1:
A coating of solidified semiconductor material is applied to the inner surface of the crucible, creating an intermediary layer that separates the liquid semiconductor material from the crucible wall. This prevents contamination while maintaining effective containment of the molten material during the monocrystalline growth process
Solution Approach 2:
The crucible surface properties are changed by coating it with solidified semiconductor material, transforming it from a potentially contaminating surface to a compatible, non-contaminating surface that allows high-purity material processing while maintaining containment
3Productivity
If polycrystalline silicon is converted to monocrystalline form through melting and crystallization, then efficiency is improved, but process complexity and energy consumption increase
Solution Approach 1:
The crucible is pre-coated with solidified semiconductor material before introducing the polycrystalline silicon charge. This preliminary preparation enables direct growth of monocrystalline material from the polycrystalline charge without requiring intermediate purification steps, simplifying the overall process while maintaining high efficiency
Solution Approach 2:
The solidified coating material serves as an intermediary substrate that facilitates the transformation of polycrystalline silicon to monocrystalline form. It provides a controlled environment for crystal growth, enabling efficient conversion while reducing process complexity compared to conventional multi-stage methods
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 simplifies the process sequence, reduces energy consumption, and maintains high purity by minimizing contact with crucible walls, resulting in monocrystalline silicon with enhanced efficiency and purity.
Implementation Method 1
the heating zone comprises at least one induction heater
Implementation Method 2
there is a melt made of the semiconductor material, which is fed with the starting material
Implementation Method 3
By lowering the melt from the heating zone or alternatively by raising the heating zone, the formation of a solidification front at the lower end of the melt can be brought about
Data Source
Figure 1
AI summary
The invention relates to a method for producing a monocrystalline semiconductor material, in which a semiconductor material is provided as starting material, the starting material is transferred to a heating zone in which the starting material is fed to the melt made of the semiconductor material and the melt is lowered out of the heating zone and/or the heating zone is raised, so that at the lower end of the melt a solidification front is formed, along which the semiconductor material crystallises in the desired structure.The starting material is prepared from the semiconductor material in liquid form and is fed in the liquid state to the melt. The invention further relates to a system for producing a monocrystalline semiconductor material, comprising a source for a liquid semiconductor material serving as the starting material, heating means for producing and/or maintaining a melt made of the semiconductor material, and preferably also means for the controlled feeding of the liquid semiconductor material serving as the starting material to the melt.