Epitaxial graphene growth on cubic silicon carbide on silicon with high temperature neutron reflectometry: an operando study.

Pradeepkumar, A; Cortie, D; Smyth, E; Le Brun, AP; Iacopi, F

Epitaxial graphene growth on cubic silicon carbide on silicon with high temperature neutron reflectometry: an operando study.

Pradeepkumar, A Cortie, D Smyth, E Le Brun, AP Iacopi, F

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Publisher:: Royal Society of Chemistry (RSC)
Publication Type:: Journal Article
Citation:: RSC Adv, 2024, 14, (5), pp. 3232-3240
Issue Date:: 2024-01-17

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Field	Value	Language
dc.contributor.author	Pradeepkumar, A
dc.contributor.author	Cortie, D
dc.contributor.author	Smyth, E
dc.contributor.author	Le Brun, AP
dc.contributor.author	Iacopi, F https://orcid.org/0000-0002-3196-0990
dc.date.accessioned	2024-02-02T00:49:03Z
dc.date.available	2024-01-13
dc.date.available	2024-02-02T00:49:03Z
dc.date.issued	2024-01-17
dc.identifier.citation	RSC Adv, 2024, 14, (5), pp. 3232-3240
dc.identifier.issn	2046-2069
dc.identifier.issn	2046-2069
dc.identifier.uri	http://hdl.handle.net/10453/175264
dc.description.abstract	The growth of graphene on silicon carbide on silicon offers a very attractive route towards novel wafer-scale photonic and electronic devices that are easy to fabricate and can be integrated in silicon manufacturing. Using a Ni/Cu catalyst for the epitaxial growth of graphene has been successful in the mitigation of the very defective nature of the underlying silicon carbide on silicon, leading to a consistent graphene coverage over large scales. A more detailed understanding of this growth mechanism is warranted in order to further optimise the catalyst composition, preferably via the use of operando characterization measurements. Here, we report in situ neutron reflectometry measurements of (Ni, Cu)/SiC films on silicon wafers, annealed from room temperature to 1100 °C, which initiates graphene formation at the buried (Ni, Cu)/SiC interface. Detailed modelling of the high temperature neutron reflectometry and corresponding scattering length density profiles yield insights into the distinct physical mechanisms within the different temperature regimes. The initially smooth solid metallic layers undergo intermixing and roughening transitions at relatively low temperatures below 500 °C, and then metal silicides begin to form above 600 °C from interfacial reactions with the SiC, releasing atomic carbon. At the highest temperature range of 600-1100 °C, the low neutron scattering length density at high temperature is consistent with a silicon-rich, liquid surface phase corresponding to molten nickel silicides and copper. This liquid catalyst layer promotes the liquid-phase epitaxial growth of a graphene layer by precipitating the excess carbon available at the SiC/metal interface.
dc.language	eng
dc.publisher	Royal Society of Chemistry (RSC)
dc.relation	http://purl.org/au-research/grants/arc/CE200100010
dc.relation.ispartof	RSC Adv
dc.relation.isbasedon	10.1039/d3ra08289j
dc.rights	info:eu-repo/semantics/openAccess
dc.subject	03 Chemical Sciences
dc.subject.classification	34 Chemical sciences
dc.title	Epitaxial graphene growth on cubic silicon carbide on silicon with high temperature neutron reflectometry: an operando study.
dc.type	Journal Article
utslib.citation.volume	14
utslib.location.activity	England
utslib.for	03 Chemical Sciences
pubs.organisational-group	University of Technology Sydney
pubs.organisational-group	University of Technology Sydney/Faculty of Engineering and Information Technology
pubs.organisational-group	University of Technology Sydney/Faculty of Engineering and Information Technology/School of Electrical and Data Engineering
utslib.copyright.status	open_access	*
dc.date.updated	2024-02-02T00:48:48Z
pubs.issue	5
pubs.publication-status	Published online
pubs.volume	14
utslib.citation.issue	5

Abstract:

The growth of graphene on silicon carbide on silicon offers a very attractive route towards novel wafer-scale photonic and electronic devices that are easy to fabricate and can be integrated in silicon manufacturing. Using a Ni/Cu catalyst for the epitaxial growth of graphene has been successful in the mitigation of the very defective nature of the underlying silicon carbide on silicon, leading to a consistent graphene coverage over large scales. A more detailed understanding of this growth mechanism is warranted in order to further optimise the catalyst composition, preferably via the use of operando characterization measurements. Here, we report in situ neutron reflectometry measurements of (Ni, Cu)/SiC films on silicon wafers, annealed from room temperature to 1100 °C, which initiates graphene formation at the buried (Ni, Cu)/SiC interface. Detailed modelling of the high temperature neutron reflectometry and corresponding scattering length density profiles yield insights into the distinct physical mechanisms within the different temperature regimes. The initially smooth solid metallic layers undergo intermixing and roughening transitions at relatively low temperatures below 500 °C, and then metal silicides begin to form above 600 °C from interfacial reactions with the SiC, releasing atomic carbon. At the highest temperature range of 600-1100 °C, the low neutron scattering length density at high temperature is consistent with a silicon-rich, liquid surface phase corresponding to molten nickel silicides and copper. This liquid catalyst layer promotes the liquid-phase epitaxial growth of a graphene layer by precipitating the excess carbon available at the SiC/metal interface.

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http://hdl.handle.net/10453/175264