Silane Plasma Synthesis via Hydrogen Membrane Control
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Solution Overview
Problem
Current methods for producing disilane in microelectronics are contaminated with catalyst residues, incur high yield losses, and are not cost-effective for high-purity production, particularly due to the use of catalytic hydrogenation and discontinuous reactor operations.
Innovation Solution
A process involving a gas-phase treatment of monosilane with hydrogen in a non-thermal plasma at reduced pressures and temperatures below 190°C, using a hydrogen-permeable membrane to set the hydrogen partial pressure ratio, resulting in the selective formation of high-purity dimeric and trimeric silanes without catalyst residues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If catalytic hydrogenation is used to produce disilane, then the production cost is reduced, but the disilane becomes contaminated with catalyst residues
Solution Approach 1:
The invention extracts and removes the catalyst from the production process entirely, replacing it with a photochemical method using UV irradiation. This eliminates the source of contamination while maintaining production feasibility, directly resolving the contradiction between cost-effectiveness and product purity.
Solution Approach 2:
The invention replaces the chemical catalytic mechanism with a photochemical mechanism using UV light irradiation. This substitution eliminates the need for metal catalysts and their associated residues, achieving high purity disilane without compromising the production process.
2Adaptability or versatility
If discontinuous reactor operation is used, then the production flexibility is improved, but the productivity decreases
Solution Approach 1:
The invention enables continuous operation of the photolysis reactor, where monosilane and hydrogen gases continuously flow through the reaction zone under UV irradiation. This continuous process maintains production flexibility while significantly increasing productivity compared to discontinuous batch operations.
3Device complexity
If hydrogen is removed from reaction products by stripping, then the separation is simplified, but yield losses occur due to stripping effects
Solution Approach 1:
The invention uses cryogenic condensation at low temperatures to separate disilane from the reaction mixture. Disilane condenses into a liquid phase while hydrogen and excess monosilane remain gaseous, enabling efficient separation without the yield losses associated with hydrogen stripping 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 method enables continuous, selective, and high-purity production of disilane and trisilane, avoiding contamination and yield losses, with optimized process conditions ensuring efficient radical formation and recombination, and allowing for subsequent purification through condensation and distillation.
Implementation Method 1
exposed to a gas discharge, preferably at a pressure between 0.05 mbar abs. up to 15000 mbar abs., preferably at reduced pressure, and particularly preferably the gas discharge corresponds to a non-thermal plasma
Implementation Method 2
a non-thermal plasma at temperatures below 190° C. and preferably reduced pressure selectively leads to the formation of disilane and/or trisilane
Implementation Method 3
a defined ratio of the hydrogen partial pressure to the partial pressure of the silanes, which are gaseous under the selected conditions, is set by means of a hydrogen-permeable membrane
Implementation Method 4
allowing for subsequent purification through condensation and distillation
Data Source
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AI summary
The invention relates to a method for preparing dimeric and/or trimeric silanes by the conversion of monosilane in a plasma and to a plant for carrying out the method.