First-Principles Mechanistic Study of the Initial Growth of SrO by Atomic Layer Deposition on TiO2-Terminated SrTiO3 (001)

2020 ◽  
Vol 124 (51) ◽  
pp. 28116-28122
Author(s):  
Renqin Zhang ◽  
Gyeong S. Hwang
Keyword(s):  
Atomic Layer Deposition ◽  
First Principles ◽  
Atomic Layer ◽  
Mechanistic Study ◽  
Initial Growth ◽  
Layer Deposition

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 ◽  
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.

Atomic Layer Deposition of Ruthenium Films on Hydrogen terminated Silicon

2009 ◽  
Vol 1156 ◽  
Author(s):  
Sun Kyung Park ◽  
K. Roodenko ◽  
Yves J. Chabal ◽  
L. Wielunski ◽  
R. Kanjolia ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Atomic Layer ◽  
Initial Growth ◽  
Experimental Conditions ◽  
Metallic Component ◽  
Broadband Absorption ◽  
Lorentz Oscillator ◽  
Layer Deposition ◽  
Drude Term ◽  
Number Of Cycles

AbstractAtomic Layer deposition of thin Ruthenium films has been studied using a newly synthesized precursor (Cyclopentadienyl ethylruthenium dicarbonyl) and O2 as reactant gases. Under our experimental conditions, the film comprises both Ru and RuO2. The initial growth is dominated by Ru metal. As the number of cycles is increased, RuO2 appears. From infrared broadband absorption measurements, the transition from isolated, nucleated film to a continuous, conducting film (characterized by Drude absorption) can be determined. Optical simulations based on an effective-medium approach are implemented to simulate the in-situ broadband infrared absorption. A Lorentz oscillator model is developed, together with a Drude term for the metallic component, to describe optical properties of Ru/RuO2 growth.

scholarly journals Nucleation Studies of HfO2 Thin Films Produced by Atomic Layer Deposition

2007 ◽  
Vol 996 ◽  
Author(s):  
Justin C. Hackley ◽  
J. Derek Demaree ◽  
Theodosia Gougousi
Keyword(s):  
Thin Films ◽  
Atomic Layer Deposition ◽  
Photoelectron Spectroscopy ◽  
Flow Reactor ◽  
Atomic Layer ◽  
Sample Surface ◽  
Interfacial Region ◽  
Initial Growth ◽  
Layer Deposition ◽  
Similar Growth

AbstractA hot wall Atomic Layer Deposition (ALD) flow reactor equipped with a Quartz Crystal Microbalance (QCM) has been used for the deposition of HfO2 thin films with tetrakis (dimethylamino) hafnium (TDMAH) and H2O as precursors. HfO2 films were deposited on H-terminated Si and SC1 chemical oxide starting surfaces. Spectroscopic ellipsometry (SE) and QCM measurements confirm linear growth of the films at a substrate temperature of 275°C. FTIR spectra indicate the films are amorphous as-deposited. Two distinct growth regimes are observed: from 1-50 cycles, both surfaces display similar growth rates of about 1.0Å/cycle; from 50-200 cycles, HfO2 growth is decreased by about 15% to ~0.87Å/cycle on both surfaces. Nucleation and initial growth behavior of the films on Si-H were examined using X-ray photoelectron spectroscopy (XPS). Angle-resolved XPS, at take-off angles of θ=0, 15, 30, 45 and 60° measured from the normal to the sample surface, is used to probe the interfacial region of thin films (4, 7, 10, 15 and 25 cycles) on H-terminated samples. Initially, an interfacial layer comprised of a SiOx/HfSiOx mixture is grown between 1-10 ALD cycles. We observe that the Si/HfO2 interface is unstable, and oxidation continues up to the 25th ALD cycle, reaching a thickness of ~18Å.

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.

Chemistry of active oxygen in RuOx and its influence on the atomic layer deposition of TiO2 films

2014 ◽  
Vol 2 (46) ◽  
pp. 9993-10001 ◽  
Author(s):  
Woojin Jeon ◽  
Woongkyu Lee ◽  
Yeon Woo Yoo ◽  
Cheol Hyun An ◽  
Jeong Hwan Han ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Crucial Role ◽  
Growth Stage ◽  
Catalytic Decomposition ◽  
Atomic Layer ◽  
Active Oxygen ◽  
Initial Growth ◽  
Tio2 Films ◽  
Initial Growth Stage ◽  
Layer Deposition

The catalytic decomposition of RuO2 with the help of Ru in the film played the crucial role for the increase in the active oxygen, which results that the growth per cycle of TiO2 at the initial growth stage was drastically increased on RuOx (RuO2/Ru mixture) compared to Ru and RuO2.

scholarly journals Dissociation reaction of B2H6 on TiN surfaces during atomic layer deposition: first-principles study

RSC Advances ◽  
2017 ◽  
Vol 7 (88) ◽  
pp. 55750-55755 ◽  
Author(s):  
Hwanyeol Park ◽  
Sungwoo Lee ◽  
Ho Jun Kim ◽  
Euijoon Yoon ◽  
Gun-Do Lee
Keyword(s):  
Atomic Layer Deposition ◽  
First Principles ◽  
Atomic Layer ◽  
Fabrication Process ◽  
Device Performance ◽  
Memory Devices ◽  
Dissociation Reaction ◽  
First Principles Study ◽  
Layer Deposition

In the fabrication process of memory devices, a void-free tungsten (W) gate process with good conformability is very important for improving the conductivity of the W gate, leading to enhancement of device performance.

Initial growth, refractive index, and crystallinity of thermal and plasma-enhanced atomic layer deposition AlN films

2015 ◽  
Vol 33 (1) ◽  
pp. 01A111 ◽  
Author(s):  
Hao Van Bui ◽  
Frank B. Wiggers ◽  
Anubha Gupta ◽  
Minh D. Nguyen ◽  
Antonius A. I. Aarnink ◽  
...  
Keyword(s):  
Refractive Index ◽  
Atomic Layer Deposition ◽  
Atomic Layer ◽  
Initial Growth ◽  
Layer Deposition
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