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

2018 ◽  
Vol 20 (35) ◽  
pp. 22783-22795 ◽  
Author(s):  
Glen N. Fomengia ◽  
Michael Nolan ◽  
Simon D. Elliott
Keyword(s):  
Atomic Layer Deposition ◽  
First Principles ◽  
Oxygen Plasma ◽  
Atomic Layer ◽  
Mechanistic Study ◽  
Alumina Surface ◽  
Layer Deposition ◽  
Surface Hydroxyls ◽  
Plasma Pulse

Saturation takes place during the oxygen plasma pulse when 1O atoms oxidize the methyl-covered alumina surface to produce surface hydroxyls and CH2O as by-product.

scholarly journals First Principles Mechanistic Study of Self-Limiting Oxidative Adsorption of Remote Oxygen Plasma During the Atomic Layer Deposition of Alumina

2018 ◽  
Author(s):  
Glen N. Fomengia ◽  
Michael Nolan ◽  
Simon D. Elliott
Keyword(s):  
Atomic Layer Deposition ◽  
First Principles ◽  
Density Functional ◽  
Atomic Layer ◽  
Molecular Water ◽  
Mechanistic Study ◽  
Hydroxyl Groups ◽  
Layer Deposition ◽  
Surface Intermediates ◽  
By Products

Plasma-enhanced atomic layer deposition (ALD) of metal oxides is a 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 O<sub>2</sub>-plasma or O<sub>3</sub> 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 –CH<sub>3</sub> ligands. Surface hydroxyl groups are the most frequently observed intermediate 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, CH<sub>2</sub>O, 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 CH<sub>3</sub> 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.

scholarly journals First Principles Mechanistic Study of Self-Limiting Oxidative Adsorption of Remote Oxygen Plasma During the Atomic Layer Deposition of Alumina

2018 ◽  
Author(s):  
Glen N. Fomengia ◽  
Michael Nolan ◽  
Simon D. Elliott
Keyword(s):  
Atomic Layer Deposition ◽  
First Principles ◽  
Density Functional ◽  
Atomic Layer ◽  
Molecular Water ◽  
Mechanistic Study ◽  
Hydroxyl Groups ◽  
Layer Deposition ◽  
Surface Intermediates ◽  
By Products

Plasma-enhanced atomic layer deposition (ALD) of metal oxides is a 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 O<sub>2</sub>-plasma or O<sub>3</sub> 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 –CH<sub>3</sub> ligands. Surface hydroxyl groups are the most frequently observed intermediate 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, CH<sub>2</sub>O, 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 CH<sub>3</sub> 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.

Influence of the oxygen plasma parameters on the atomic layer deposition of titanium dioxide

2014 ◽  
Vol 26 (2) ◽  
pp. 024003 ◽  
Author(s):  
Stephan Ratzsch ◽  
Ernst-Bernhard Kley ◽  
Andreas Tünnermann ◽  
Adriana Szeghalmi
Keyword(s):  
Titanium Dioxide ◽  
Atomic Layer Deposition ◽  
Oxygen Plasma ◽  
Atomic Layer ◽  
Plasma Parameters ◽  
Layer Deposition

Deposition of Pt Nanoparticles on Oxygen Plasma Treated Carbon Nanotubes by Atomic Layer Deposition

2019 ◽  
Vol 16 (2) ◽  
pp. 855-862 ◽  
Author(s):  
Yang-Chih Hsueh ◽  
Chia-Te Hu ◽  
Chih-Chieh Wang ◽  
Chueh Liu ◽  
Tsong-Pyng Perng
Keyword(s):  
Carbon Nanotubes ◽  
Atomic Layer Deposition ◽  
Oxygen Plasma ◽  
Pt Nanoparticles ◽  
Atomic Layer ◽  
Layer Deposition ◽  
Treated Carbon

Chemical Protection of Polycarbonate Surfaces by Atomic Layer Deposition of Alumina with Oxygen Plasma Pretreatment

2016 ◽  
Vol 3 (21) ◽  
pp. 1600340 ◽  
Author(s):  
Suk Won Park ◽  
Kiho Bae ◽  
Jun Woo Kim ◽  
Gyeong Beom Lee ◽  
Byoung-Ho Choi ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Oxygen Plasma ◽  
Atomic Layer ◽  
Chemical Protection ◽  
Layer Deposition ◽  
Plasma Pretreatment

Plasma Enhanced Atomic Layer Deposition of Nickel and Cobalt Phosphate for Lithium Ion Batteries

2022 ◽  
Author(s):  
Lowie Henderick ◽  
Ruben Blomme ◽  
Matthias Marcus Minjauw ◽  
Jonas Keukelier ◽  
Johan Meersschaut ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Substrate Temperature ◽  
Lithium Ion Batteries ◽  
Oxygen Plasma ◽  
Lithium Ion ◽  
Atomic Layer ◽  
Layer Deposition ◽  
Nickel Phosphate ◽  
Cobalt Phosphate

A plasma-enhanced ALD process has been developed to deposit nickel phosphate. The process combines a trimethylphosphate (TMP) plasma with an oxygen plasma and nickelocene at a substrate temperature of 300°C....

scholarly journals First-principles study of the surface reactions of aminosilane precursors over WO3(001) during atomic layer deposition of SiO2

RSC Advances ◽  
2020 ◽  
Vol 10 (28) ◽  
pp. 16584-16592
Author(s):  
Kyungtae Lee ◽  
Youngseon Shim
Keyword(s):  
Atomic Layer Deposition ◽  
First Principles ◽  
Surface Reactions ◽  
Atomic Layer ◽  
Reaction Pathways ◽  
Energy Diagram ◽  
First Principles Study ◽  
Layer Deposition

Energy diagram of reaction pathways for decomposition of different aminosilane precursors on a WO3 (001) surface.

Atomic Layer Deposition of Lithium-Silicon-Tin Oxide Nanofilms for High Performance Thin Film Batteries Anodes

2020 ◽  
Vol 299 ◽  
pp. 1058-1063
Author(s):  
Denis Nazarov ◽  
Ilya Mitrofanov ◽  
Maxim Yu. Maximov
Keyword(s):  
Thin Film ◽  
Stainless Steel ◽  
Atomic Layer Deposition ◽  
Tin Oxide ◽  
Oxygen Plasma ◽  
Atomic Layer ◽  
Cycling Performance ◽  
Spectral Ellipsometry ◽  
X Ray ◽  
Layer Deposition

Tin oxide is the most promising material for thin film anodes of Li-ion batteries due to its cycling performance and high theoretical capacity. It is assumed that lithium-tin oxide can demonstrate even higher performance. Lithium-silicon-tin oxide nanofilms were prepared by atomic layer deposition (ALD), using the lithium bis (trimethylsilyl) amide (LiHMDS), tetraethyltin (TET) as a metal containing reagents and ozone or water or oxygen plasma as counter-reactants. Monocrystalline silicon (100) and stainless steel (316SS) were used as supports. The thicknesses of the nanofilms were measured by spectral ellipsometry (SE) and scanning electron microscopy (SEM). It was found that oxygen plasma is the most optimal ALD counter-reactant. The composition and structure were studied by Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS), X-ray Photoelectron Spectroscopy (XPS) and X-ray diffraction (XRD). The nanofilms contain silicon as impurity, whose source is the ALD precursor (LiHMDS). The nanofilms deposited on stainless steel have shown the high Coulombic efficiency (99.1-99.8%) and cycling performance at a relatively high voltage (0.01 to 2.0V).

Sign in / Sign up

Export Citation Format

Share Document