Continuous Silicon Vapor Deposition With Gas Recirculation Control
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Solution Overview
Problem
Chemical vapor deposition of silicon in existing processes leads to parasitic deposits in reaction chamber conduits, reducing throughput and increasing costs due to the need for frequent cleaning and conversion of silicon layers into gasous trichlorosilane by hydrogen chloride, which also reduces layer thickness.
Innovation Solution
A process and apparatus where the molar ratio of silicon-based intermediates to silicon precursor compounds is controlled between 0.2:0.8 to 0.5:0.5, with recirculation of excess constituents to prevent parasitic deposits, optimizing deposition rates and reducing waste and costs by maintaining a stable molar composition and recirculating process gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If hydrogen chloride is fed into the reaction chamber to remove parasitic deposits, then parasitic deposits are removed, but substrate throughput decreases significantly
Solution Approach 1:
The patent changes the chemical parameters by introducing a silicon precursor compound that reacts with hydrogen chloride to form a gaseous mixture, thereby converting the harmful parasitic deposits into removable gaseous products without requiring chamber cleaning interruptions
Solution Approach 2:
The patent converts the harmful parasitic deposits into beneficial gaseous trichlorosilane by reacting them with silicon precursor compound and hydrogen chloride, transforming a cleaning problem into a continuous chemical conversion process that maintains throughput
2Object-generated harmful factors
If hydrogen chloride is used to remove parasitic deposits, then deposits are cleaned, but silicon layer thickness is reduced
Solution Approach 1:
The patent introduces a silicon precursor compound as an intermediary substance that reacts with hydrogen chloride to form gaseous trichlorosilane, thereby mediating between the need to remove parasitic deposits and the need to preserve silicon layer thickness on substrates
3Ease of operation
If parasitic deposits are removed regularly to maintain cross sections, then fluid flow is maintained, but production time is lost
Solution Approach 1:
The patent enables continuous operation by converting parasitic deposits into gaseous products through chemical reaction, eliminating the need for periodic cleaning interruptions and maintaining continuous substrate processing and fluid flow
4Device complexity
If excess silicon precursor compound is discharged without recirculation, then reaction chamber operates simply, but silicon consumption and costs increase
Solution Approach 1:
The patent recovers excess silicon precursor compound and gaseous trichlorosilane by discharging them to a condensation system where they are condensed and collected, then recirculated back to the reaction chamber inlet, thereby reducing silicon consumption and costs while adding a recovery loop to the system
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
Significantly reduces parasitic deposits, increases substrate throughput, and lowers silicon precursor consumption by maintaining optimal molar ratios and recirculating gases, thereby minimizing waste and production costs.
Implementation Method 1
A silicon precursor compound is then fed into the reaction chamber and decomposes thermally in the reaction chamber, as a result of which solid silicon deposits on the substrate
Implementation Method 2
The excess of the gaseous mixture is then condensed and fed back into the reaction chamber
Data Source
AI summary
A method for the continuous vapour deposition of silicon on substrates, including the following steps: a) introducing at least one substrate into a reaction chamber; b) introducing a process gas and at least one gaseous silicon precursor compound into the reaction chamber; c) forming a gaseous mixture of at least one silicon-based intermediate product coexisting with the gaseous silicon precursor compound and the process gas; d) forming a silicon layer by vapour deposition of silicon from the gaseous silicon precursor compound and/or the silicon-based intermediate product on the substrate; e) discharging an excess of the gaseous mixture from the reaction chamber; f) returning at least one of the constituents of the excess of the gaseous mixture, selected from the silicon precursor compound, the silicon-based intermediate product and/or the process gas into the reaction chamber, wherein introducing the gaseous silicon precursor compound into the reaction chamber is regulated such that the molar ratio of the silicon-based intermediate product to the silicon precursor compound has a value of 0.2:0.8 to 0.5:0.5.