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In situ size sorting in CVD synthesis of Si microspheres
M Garín1, R Fenollosa2, L Kowalski1
1Grup de recerca en Micro i Nanotecnologies, Departament d'Enginyeria Electrònica, Universitat Politècnica de Catalunya, c/Jordi Girona Pascual 1-3, Barcelona 08034, Spain.
Scientific Reports
|December 9, 2016
Summary
Researchers demonstrate that thermophoretic forces in hot-wall Chemical Vapor Deposition (CVD) reactors can sort silicon microspheres by size. This allows for the selection of specific particle sizes, enabling controlled production of high-quality silicon microspheres.
Area of Science:
- Materials Science
- Chemical Engineering
- Nanotechnology
Background:
- Silicon microspheres produced via hot-wall Chemical Vapor Deposition (CVD) exhibit excellent sphericity and surface smoothness.
- However, these CVD-produced microspheres are typically polydisperse, with sizes ranging from 0.5 to 5 micrometers.
Purpose of the Study:
- To investigate the potential of thermophoretic forces for size-sorting silicon microspheres produced by CVD.
- To demonstrate a method for controlling the size of silicon microspheres during the CVD process.
Main Methods:
- Experimental investigation of particle formation and transport within a hot-wall CVD reactor.
- Computational analysis of temperature gradients and resulting thermophoretic forces.
- Collection of microspheres from different axial regions of the reactor.
Main Results:
- Strong temperature gradients, induced by convective gas flow, were identified within the reactor.
- These temperature gradients generate thermophoretic forces that effectively sort silicon microspheres by size along the reactor's length.
- Distinct size fractions of silicon microspheres were successfully collected from specific reactor zones.
Conclusions:
- Thermophoretic forces offer a viable mechanism for size-controlling silicon microspheres produced by hot-wall CVD.
- This size-sorting capability opens new avenues for producing tailored, high-quality silicon microspheres for various applications.
