Introducing densification mechanisms into the modelling of HfO2 atomic layer deposition

Mastail, Cédric; Lanthony, Cloé; Olivier, Stéphane; Ducéré, Jean‐Marie; Landa, Georges; Estève, Alain; Rouhani, M. Djafari; Richard, Nicolas; Dkhissi, Ahmed

doi:10.1016/j.tsf.2011.10.125

Cited by 11 publications

(12 citation statements)

References 23 publications

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“…Based on our literature review, most ALD simulations were performed on large Knudsen numbers in feature scales [16][17][18][19][20][21][22][23] while reactor scale simulations are rarely investigated. Ho et al [24] investigated the ALD of Al 2 O 3 from trimethylaluminum (TMA) and ozone for different substrate temperatures through both experiments and reactor scale simulations.…”

Section: Introductionmentioning

confidence: 99%

Investigating atomic layer deposition characteristics in multi-outlet viscous flow reactors through reactor scale simulations

Shaeri

Jen

Yuan

et al. 2015

International Journal of Heat and Mass Transfer

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Section: Introductionmentioning

confidence: 99%

Investigating atomic layer deposition characteristics in multi-outlet viscous flow reactors through reactor scale simulations

Shaeri

Jen

Yuan

et al. 2015

International Journal of Heat and Mass Transfer

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“…Although the dissociation mechanism of (C 5 H 4 CH 3 )Pt(CH 3 ) 3 leading to the Pt deposit remains unknown, studies for a family of precursors similar to (C 5 H 4 CH 3 )Pt(CH 3 ) 3 in atomic layer deposition (ALD) conditions are available [ 12 ]. The studies in this review fairly agree that (1) the presence of surface hydroxyl groups are the source for protons that help in the evolution of H 2 , CH 4 and H 2 O during the deposition process, and (2) the molecules dissociate or associate through a ligand exchange process [ 13 ]. Recently, examination of the behavior of this molecule on fully hydroxylated SiO 2 surfaces has shown that the molecule remains physisorbed [ 14 ].…”

Section: Introductionmentioning

confidence: 73%

“…Although this does not account for the complete surface model, it is a good approximation to evaluate the reaction barriers for different reactions observed through the MD simulations. In the literature, such a simple hydroxylated M(OH) x model has been used as a representative model to investigate deposition reactions on Al [ 29 ], Hf [ 13 ] and Si [ 30 – 32 ]. Also, the energies reported in this section are computed at the PM6 level of theory, and a relative comparison should enable reasonable understanding of the possible fragmentation pathways qualitatively.…”

Section: Resultsmentioning

confidence: 99%

Dynamics and fragmentation mechanism of (C₅H₄CH₃)Pt(CH₃)₃ on SiO₂ surfaces

Muthukumar¹,

Jeschke²,

Valentí³

2018

Beilstein J. Nanotechnol.

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The interaction of trimethyl(methylcyclopentadienyl)platinum(IV) ((C5H4CH3)Pt(CH3)3) molecules on fully and partially hydroxylated SiO2 surfaces, as well as the dynamics of this interaction were investigated using density functional theory (DFT) and finite temperature DFT-based molecular dynamics simulations. Fully and partially hydroxylated surfaces represent substrates before and after electron beam treatment and this study examines the role of electron beam pretreatment on the substrates in the initial stages of precursor dissociation and formation of Pt deposits. Our simulations show that on fully hydroxylated surfaces or untreated surfaces, the precursor molecules remain inactivated while we observe fragmentation of (C5H4CH3)Pt(CH3)3 on partially hydroxylated surfaces. The behavior of precursor molecules on the partially hydroxylated surfaces has been found to depend on the initial orientation of the molecule and the distribution of surface active sites. Based on the observations from the simulations and available experiments, we discuss possible dissociation channels of the precursor.

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“…The term densification is used to describe the increase in coordination number of atoms in the adsorbate or at the surface as reactions occur that make them more bulk-like. Simulations indicate that densification is an important part of the mechanism of oxide ALD [27,28] and in this study we also discuss how the chemistry of the plasma pulse affects whether Al and O densify and adopt a coordination environment that can be related to a bulk phase.…”

Section: Introductionmentioning

confidence: 91%

First principles mechanistic study of self-limiting oxidative adsorption of remote oxygen plasma during the atomic layer deposition of alumina

Fomengia

Nolan

Elliott

2018

Phys. Chem. Chem. Phys.

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Plasma-enhanced atomic layer deposition (ALD) of metal oxides is rapidly gaining interest, especially in the electronics industry, because of its numerous advantages over the thermal process. However, the underlying reaction mechanism is not sufficiently understood, particularly regarding saturation of the reaction and densification of the film. In this work, we employ first principles density functional theory (DFT) to determine the predominant reaction pathways, surface intermediates and by-products formed when constituents of O2-plasma or O3 adsorb onto a methylated surface typical of TMA-based alumina ALD. The main outcomes are that a wide variety of barrierless and highly exothermic reactions can take place. This leads to the spontaneous production of various by-products with low desorption energies and also of surface intermediates from the incomplete combustion of -CH3 ligands. Surface hydroxyl groups are the most frequently observed intermediates and are formed as a consequence of the conservation of atoms and charge when methyl ligands are initially oxidized (rather than from subsequent re-adsorption of molecular water). Anionic intermediates such as formates are also commonly observed at the surface in the simulations. Formaldehyde, CH2O, is the most frequently observed gaseous by-product. Desorption of this by-product leads to saturation of the redox reaction at the level of two singlet oxygen atoms per CH3 group, where the oxidation state of C is zero, rather than further reaction with oxygen to higher oxidation states. We conclude that the self-limiting chemistry that defines ALD comes about in this case through the desorption by-products with partially-oxidised carbon. The simulations also show that densification occurs when ligands are removed or oxidised to intermediates, indicating that there may be an inverse relationship between Al/O coordination numbers in the final film and the concentration of chemically-bound ligands or intermediate fragments covering the surface during each ALD pulse. Therefore reactions that generate a bare surface Al will produce denser films in metal oxide ALD.

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Introducing densification mechanisms into the modelling of HfO2 atomic layer deposition

Cited by 11 publications

References 23 publications

Investigating atomic layer deposition characteristics in multi-outlet viscous flow reactors through reactor scale simulations

Investigating atomic layer deposition characteristics in multi-outlet viscous flow reactors through reactor scale simulations

Dynamics and fragmentation mechanism of (C₅H₄CH₃)Pt(CH₃)₃ on SiO₂ surfaces

First principles mechanistic study of self-limiting oxidative adsorption of remote oxygen plasma during the atomic layer deposition of alumina

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Introducing densification mechanisms into the modelling of HfO2 atomic layer deposition

Cited by 11 publications

References 23 publications

Investigating atomic layer deposition characteristics in multi-outlet viscous flow reactors through reactor scale simulations

Investigating atomic layer deposition characteristics in multi-outlet viscous flow reactors through reactor scale simulations

Dynamics and fragmentation mechanism of (C5H4CH3)Pt(CH3)3 on SiO2 surfaces

First principles mechanistic study of self-limiting oxidative adsorption of remote oxygen plasma during the atomic layer deposition of alumina

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Dynamics and fragmentation mechanism of (C₅H₄CH₃)Pt(CH₃)₃ on SiO₂ surfaces