Molecular beam investigation of hydrogen dissociation on Si(001) and Si(111) surfaces

Dürr, Michael; Höfer, U.

doi:10.1063/1.1797052

Cited by 22 publications

(5 citation statements)

References 79 publications

(137 reference statements)

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“…The dissociation takes place at a distance of ≈0.2 Å from the final adsorption place. This is in contrast to the H 2 behaviour at silicon surfaces Si(111)7 × 7 and Si(001)2 × 1 where there was measured a barrier for dissociation of around 0.8 eV [24]. The difference may originate from the fact that the considered SiC surfaces are unreconstructed and thus more active than silicon surfaces encountered in the experiment.…”

Section: Resultscontrasting

confidence: 61%

Structure and energetics changes during hydrogenation of 4H-SiC{0001} surfaces: a DFT study

Wachowicz

Kiejna

2012

J. Phys.: Condens. Matter

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The changes in the atomic and electronic structure of Si- and C-terminated hexagonal SiC{0001} surfaces resulting from on-surface and subsurface hydrogen adsorption have been studied within the density functional theory framework. Hydrogen coverages ranging from a submonolayer to one monolayer were considered. Our results show that a monolayer of adsorbed H almost completely suppresses the relaxation of the SiC surface atomic layers. On both terminations H binds strongly to the surface and the binding is about 2 eV stronger in on-surface sites than subsurface. Hydrogen binding to the C-terminated surface varies very little with coverage and is distinctly stronger than to the Si-terminated surface.

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Section: Resultscontrasting

confidence: 61%

Structure and energetics changes during hydrogenation of 4H-SiC{0001} surfaces: a DFT study

Wachowicz

Kiejna

2012

J. Phys.: Condens. Matter

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“…The root cause is not well understood,. 24 Chemisorption is favored by the system energy, but there is a yet unidentified energy barrier. As a result, equalization of chemical potentials is not achieved, and molecular hydrogen is not in equilibrium with the surface.…”

Section: Methodsmentioning

confidence: 99%

Chemical Vapor Deposition of Elemental Crystallogen Thin Films

Tomasini

2024

ECS J. Solid State Sci. Technol.

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A consolidation of the fundamentals of elemental crystallogen chemical vapor deposition (CVD) is a necessity in view of the extensive evidence accumulated over the last few decades. An in-depth understanding of deposition mechanisms via hydrides asks for a discerning understanding of molecular hydrogen dissociative adsorption, precursor thermal decomposition, and CVD growth rates. With those, a groundbreaking paradigm shift comes to light. GR activation energy E(GR) fingerprints the surface energy. SE ≈ 2E(GR) / (aa), where SE is surface energy, E(GR) activation energy, a lattice parameter. Hydride precursor thermal decomposition consistency with the corresponding solid growth kinetics is demonstrated. Heterogeneous TD kinetics captures a solid deposition and not a gas phase molecular reaction. Thermodynamic equilibrium is achieved during the heterogeneous thermal decomposition of silicon precursors. The popular split between mass-transfer and kinetic regimes is not supported by evidence. Three mechanisms are apparent. The first is controlled by a Si–H bond dissociation energy. The second is controlled by an H–H bond dissociation energy. The last is controlled by a Si–Si bond dissociation energy as lattice sites are sealed off with Si–H bonds.

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“…Lastly, the hydrogen carrier gas is barred from reaching the active interface. The absence of interaction between the dihydrogen carrier gas and the silicon surface is well documented . As a result, there are no electronic interactions between H 2 ( g ) and the surface, and the molecule is not part of the chemical equilibrium, eq , in spite of the identity of the reaction byproduct H 2 , with the carrier gas.…”

Section: Experiments and Methodsmentioning

confidence: 99%

“…The absence of interaction between the dihydrogen carrier gas and the silicon surface is well documented. 20 As a result, there are no electronic interactions between H 2 (g) and the surface, and the molecule is not part of the chemical equilibrium, eq 7, in spite of the identity of the reaction byproduct H 2 , with the carrier gas. In other words, the interface is isolated from carrier gas dihydrogen by a poorly understood barrier.…”

Section: Gas Depletion Along the Longitudinal Axis Of The Reactormentioning

confidence: 99%

Thermodynamic Theory of Silicon Chemical Vapor Deposition

Tomasini

2021

Chem. Mater.

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Silicon chemical vapor deposition via silane is determined with classical thermodynamics. Drastic assumptions are used, such as the hydrogen carrier gas does not interact with the silicon thin film growth and the energy of reaction is adjusted to experiments. As a result, a linear function of temperature akin to a Gibbs free energy of reaction is shown to control silicon growth rates, and the characteristic Arrhenius plot is fully determined. The surface response of the growth rate activation energy is neatly mapped, bringing clarity to the parameter space for which a single value is a valid metric. A meta-analysis of growth rates is carried out for a demonstration of the portability of the linear function of temperature across reactors and to mine out reactor scaling factors. A silane heterogeneous decomposition reaction is also a great model chemistry for chlorosilanes. Silicon deposition is notoriously a complex chemical process, but with thermodynamics, the reaction mechanism is successfully reduced to the essentials.

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Molecular beam investigation of hydrogen dissociation on Si(001) and Si(111) surfaces

Cited by 22 publications

References 79 publications

Structure and energetics changes during hydrogenation of 4H-SiC{0001} surfaces: a DFT study

Structure and energetics changes during hydrogenation of 4H-SiC{0001} surfaces: a DFT study

Chemical Vapor Deposition of Elemental Crystallogen Thin Films

Thermodynamic Theory of Silicon Chemical Vapor Deposition

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