Computational Study of Surface Deposition and Gas Phase Powder Formation during Spinel Chemical Vapor Deposition Processes

Chemical vapor deposition (CVD) processes are often employed to produce high quality materials. In some applications, a relatively fast deposition rate is required to produce thick pieces of material, e.g., on the order of centimeter, in an economical manner. However, in some processes the formation...

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Main Authors:	Wang, H., Stern, H., Chakraborty, D., Bai, H., DiFilippo, V., Goela, J., Pickering, M., Gale, Julian
Format:	Journal Article
Published:	American Chemical Society 2013
Online Access:	http://hdl.handle.net/20.500.11937/5855

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recordtype	eprints
spelling	curtin-20.500.11937-58552017-09-13T14:41:03Z Computational Study of Surface Deposition and Gas Phase Powder Formation during Spinel Chemical Vapor Deposition Processes Wang, H. Stern, H. Chakraborty, D. Bai, H. DiFilippo, V. Goela, J. Pickering, M. Gale, Julian Chemical vapor deposition (CVD) processes are often employed to produce high quality materials. In some applications, a relatively fast deposition rate is required to produce thick pieces of material, e.g., on the order of centimeter, in an economical manner. However, in some processes the formation of solid nuclei or powder in the gas phase can be a major obstacle to increasing the deposition rate. The homogeneous powder formation reaction can compete with the surface deposition reaction and consume the gas phase reactants, thus reducing the available material to grow on the substrate surface. Understanding the thermodynamics as well as kinetics of these two competing reactions helps elucidate the reaction conditions that best reduce powder formation and increase deposition rate. As an example where gas phase powder formation can significantly limit the surface deposition rate CVD growth of spinel (MgAl2O4) is investigated. In this CVD process, reverse water gas shift (rWGS) is employed to generate water, which reacts with either chlorides or fluorides of magnesium and aluminum to produce spinel. Density functional theory (DFT) was used to study the thermodynamics of surface reactions of spinel deposition. This study shows that the surface reaction to form spinel is thermodynamically favorable. However, the spinel deposition could be limited by its surface kinetics and/or competition for reactants with gas phase powder formation. We have employed molecular dynamics (MD) with a reactive force field (ReaxFF) to simulate gas phase rWGS and powder formation. These simulations show that the reactants’ residence time should be minimized to reduce powder formation. A comparison of magnesium and aluminum chlorides with their corresponding fluorides indicates that fluorides are better in reducing powder formation. 2013 Journal Article http://hdl.handle.net/20.500.11937/5855 10.1021/ie400502u American Chemical Society restricted
repository_type	Digital Repository
institution_category	Local University
institution	Curtin University Malaysia
building	Curtin Institutional Repository
collection	Online Access
description	Chemical vapor deposition (CVD) processes are often employed to produce high quality materials. In some applications, a relatively fast deposition rate is required to produce thick pieces of material, e.g., on the order of centimeter, in an economical manner. However, in some processes the formation of solid nuclei or powder in the gas phase can be a major obstacle to increasing the deposition rate. The homogeneous powder formation reaction can compete with the surface deposition reaction and consume the gas phase reactants, thus reducing the available material to grow on the substrate surface. Understanding the thermodynamics as well as kinetics of these two competing reactions helps elucidate the reaction conditions that best reduce powder formation and increase deposition rate. As an example where gas phase powder formation can significantly limit the surface deposition rate CVD growth of spinel (MgAl2O4) is investigated. In this CVD process, reverse water gas shift (rWGS) is employed to generate water, which reacts with either chlorides or fluorides of magnesium and aluminum to produce spinel. Density functional theory (DFT) was used to study the thermodynamics of surface reactions of spinel deposition. This study shows that the surface reaction to form spinel is thermodynamically favorable. However, the spinel deposition could be limited by its surface kinetics and/or competition for reactants with gas phase powder formation. We have employed molecular dynamics (MD) with a reactive force field (ReaxFF) to simulate gas phase rWGS and powder formation. These simulations show that the reactants’ residence time should be minimized to reduce powder formation. A comparison of magnesium and aluminum chlorides with their corresponding fluorides indicates that fluorides are better in reducing powder formation.
format	Journal Article
author	Wang, H. Stern, H. Chakraborty, D. Bai, H. DiFilippo, V. Goela, J. Pickering, M. Gale, Julian
spellingShingle	Wang, H. Stern, H. Chakraborty, D. Bai, H. DiFilippo, V. Goela, J. Pickering, M. Gale, Julian Computational Study of Surface Deposition and Gas Phase Powder Formation during Spinel Chemical Vapor Deposition Processes
author_facet	Wang, H. Stern, H. Chakraborty, D. Bai, H. DiFilippo, V. Goela, J. Pickering, M. Gale, Julian
author_sort	Wang, H.
title	Computational Study of Surface Deposition and Gas Phase Powder Formation during Spinel Chemical Vapor Deposition Processes
title_short	Computational Study of Surface Deposition and Gas Phase Powder Formation during Spinel Chemical Vapor Deposition Processes
title_full	Computational Study of Surface Deposition and Gas Phase Powder Formation during Spinel Chemical Vapor Deposition Processes
title_fullStr	Computational Study of Surface Deposition and Gas Phase Powder Formation during Spinel Chemical Vapor Deposition Processes
title_full_unstemmed	Computational Study of Surface Deposition and Gas Phase Powder Formation during Spinel Chemical Vapor Deposition Processes
title_sort	computational study of surface deposition and gas phase powder formation during spinel chemical vapor deposition processes
publisher	American Chemical Society
publishDate	2013
url	http://hdl.handle.net/20.500.11937/5855
first_indexed	2018-09-06T18:03:44Z
last_indexed	2018-09-06T18:03:44Z
_version_	1610882246180339712

Computational Study of Surface Deposition and Gas Phase Powder Formation during Spinel Chemical Vapor Deposition Processes

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