Growth and characterization of Al2O3 films on fluorine functionalized epitaxial graphene

Intelligent engineering of graphene-based electronic devices on SiC(0001) requires a better understanding of processes used to deposit gate-dielectric materials on graphene. Recently, Al2O3 dielectrics have been shown to form conformal, pinhole-free thin films by functionalizing the top surface of t...

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Bibliographic Details
Published in:	Journal of applied physics 2016-08, Vol.120 (7)
Main Authors:	Robinson, Zachary R., Jernigan, Glenn G., Wheeler, Virginia D., Hernández, Sandra C., Eddy, Charles R., Mowll, Tyler R., Ong, Eng Wen, Ventrice, Carl A., Geisler, Heike, Pletikosic, Ivo, Yang, Hongbo, Valla, Tonica
Format:	Article
Language:	eng
Subjects:	Adsorption Aluminum oxide Atomic layer epitaxy Dielectrics Electronic devices Electronic structure Electrons Epitaxial growth Fluorine Graphene In situ measurement Low energy electron diffraction Pinholes Precursors Silicon substrates Spectrum analysis Surface chemistry Thin films X ray photoelectron spectroscopy
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Summary:	Intelligent engineering of graphene-based electronic devices on SiC(0001) requires a better understanding of processes used to deposit gate-dielectric materials on graphene. Recently, Al2O3 dielectrics have been shown to form conformal, pinhole-free thin films by functionalizing the top surface of the graphene with fluorine prior to atomic layer deposition (ALD) of the Al2O3 using a trimethylaluminum (TMA) precursor. In this work, the functionalization and ALD-precursor adsorption processes have been studied with angle-resolved photoelectron spectroscopy, low energy electron diffraction, and X-ray photoelectron spectroscopy. It has been found that the functionalization process has a negligible effect on the electronic structure of the graphene, and that it results in a twofold increase in the adsorption of the ALD-precursor. In situ TMA-dosing and XPS studies were also performed on three different Si(100) substrates that were terminated with H, OH, or dangling Si-bonds. This dosing experiment revealed that OH is required for TMA adsorption. Based on those data along with supportive in situ measurements that showed F-functionalization increases the amount of oxygen (in the form of adsorbed H2O) on the surface of the graphene, a model for TMA-adsorption on graphene is proposed that is based on a reaction of a TMA molecule with OH.
ISSN:	0021-8979 1089-7550