Polysilane Production via Non-Thermal Plasma and Membrane
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Solution Overview
Problem
Current methods for producing high-purity disilane in microelectronics are inefficient, often requiring catalytic processes that lead to contamination and high yield losses, and are not suitable for continuous production.
Innovation Solution
A process involving the reaction of monosilane with hydrogen in a non-thermal plasma at reduced pressure, using a hydrogen-permeable membrane to adjust the hydrogen partial pressure and achieve high-purity polysilane mixtures, which can be separated by distillation or chromatography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If catalytic processes are used for producing disilane, then production can be achieved, but contamination occurs and yield losses increase
Solution Approach 1:
The patent removes the catalyst component from the production process entirely, using instead a plasma-based method that converts monosilane to disilane without any catalytic agents. This extraction of the harmful catalytic element eliminates the source of contamination while maintaining production capability through an alternative reaction mechanism.
Solution Approach 2:
The patent replaces the chemical catalytic mechanism with a physical plasma-based mechanism. Instead of using chemical catalysts to facilitate the reaction, the invention employs plasma energy to directly convert monosilane to disilane, substituting a physical process for a chemical one and thereby eliminating catalyst-related contamination.
2Quantity of substance
If catalytic hydrogenation is used to produce disilane, then disilane can be obtained, but contamination with catalyst residues occurs
Solution Approach 1:
The patent extracts and removes the catalyst from the hydrogenation process, replacing it with a plasma-based conversion method. This eliminates catalyst residues and contamination while maintaining the ability to produce disilane from monosilane and hydrogen through a catalyst-free reaction pathway.
Solution Approach 2:
The patent employs a disposable plasma state rather than reusable catalysts. The plasma is generated temporarily to facilitate the reaction and then dissipates, leaving no persistent contaminating residues. This approach replaces long-lived catalyst materials with a transient energy state that completes its function and disappears without trace.
3Productivity
If continuous production is implemented, then productivity increases, but process complexity increases
Solution Approach 1:
The patent implements continuous production by maintaining a continuous plasma discharge through the monosilane-hydrogen gas mixture. The plasma reactor operates continuously, converting monosilane to disilane in an ongoing process without interruption, thereby achieving continuous production with a relatively simple single-stage configuration.
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 method enables the continuous production of high-purity polysilanes with reduced contamination and yield losses, allowing for direct processing into high-purity silicon layers without additional cleaning steps, and is economically viable on an industrial scale.
Implementation Method 1
a stream of reactants comprising monosilane of general formula I and hydrogen, and the stream of reactants has a hydrogen to monosilane ratio in volume percent (vol%) of 15:1 to 1:5, ii) is subjected to at least one gas discharge, preferably two to ten non-thermal plasmas
Implementation Method 2
gas phase treatments of a stream of reactants comprising monosilane with a defined monosilane partial pressure in the gas mixture in the presence of hydrogen in non-thermal plasmas at temperatures below 40 °C
Implementation Method 3
in the resulting phase the defined ratio of the hydrogen partial pressure to the partial pressure of the silanes gaseous under the selected conditions is set by means of a hydrogen-permeable membrane
Implementation Method 4
a hydrogen-permeable membrane, which is preferably permeable only to hydrogen and essentially not to silanes
Implementation Method 5
the polysilane mixture is separated, in particular by distillation, fractional condensation and/or chromatography
Data Source
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AI summary
The invention relates to a process for preparing polysilanes by converting monosilane in the presence of hydrogen in a plasma, and to a plant for performing the process.