Theoretical Investigation of Fluorinated and Hydrocenated Diamond Filks

1992 ◽  
Vol 270 ◽  
Author(s):  
Mark R. Pederson ◽  
Warren E. Pickett
Keyword(s):  
Density Functional ◽  
Film Growth ◽  
Growth Models ◽  
Diamond Films ◽  
Diamond Surface ◽  
Free Standing ◽  
Level Shifts ◽  
Reconstructed Surface ◽  
Experimental Values ◽  
Diamond Film Growth

ABSTRACTTo investigate some of the fundamental differences between halogen and hydrogen assisted diamond film growth we have performed several calculations related to the <100> diamond surface. The models used in these investigations include ten-layer periodic slabs of free standing fluorinated diamond films as well as isolated clusters [C21F6H20]. For purposes of comparison, we have also performed calculations on models of the hydrogenated <100> surface. The calculations are performed within the density-functional framework using LCAO and LAPW computational methods. We have considered two geometries of a monofluoride surface. The first surface, best described as an ideal l×l surface with a monolayer of ionically bonded fluorines, exhibits a metallic density of states in contrast to a 2×l reconstructed surface with chemically bonded fluorines that is found to be insulating. We compare theoretical carbon core level shifts with experimental values and discuss growth models based on these surface calculations.

scholarly journals Effect of Nitrogen on the Growth of (100)-, (110)-, and (111)-Oriented Diamond Films

2020 ◽  
Vol 11 (1) ◽  
pp. 126
Author(s):  
Jen-Chuan Tung ◽  
Tsung-Che Li ◽  
Yen-Jui Teseng ◽  
Po-Liang Liu
Keyword(s):  
Growth Mechanism ◽  
Density Functional ◽  
Film Growth ◽  
Hydrogen Abstraction ◽  
Diamond Films ◽  
Activation Energies ◽  
Diamond Surface ◽  
Nitrogen Doped ◽  
Nitrogen Substitution ◽  
Diamond Film Growth

The aim of this research is the study of hydrogen abstraction reactions and methyl adsorption reactions on the surfaces of (100), (110), and (111) oriented nitrogen-doped diamond through first-principles density-functional calculations. The three steps of the growth mechanism for diamond thin films are hydrogen abstraction from the diamond surface, methyl adsorption on the diamond surface, and hydrogen abstraction from the methylated diamond surface. The activation energies for hydrogen abstraction from the surface of nitrogen-undoped and nitrogen-doped diamond (111) films were −0.64 and −2.95 eV, respectively. The results revealed that nitrogen substitution was beneficial for hydrogen abstraction and the subsequent adsorption of methyl molecules on the diamond (111) surface. The adsorption energy for methyl molecules on the diamond surface was generated during the growth of (100)-, (110)-, and (111)-oriented diamond films. Compared with nitrogen-doped diamond (100) films, adsorption energies for methyl molecule adsorption were by 0.14 and 0.69 eV higher for diamond (111) and (110) films, respectively. Moreover, compared with methylated diamond (100), the activation energies for hydrogen abstraction were by 0.36 and 1.25 eV higher from the surfaces of diamond (111) and (110), respectively. Growth mechanism simulations confirmed that nitrogen-doped diamond (100) films were preferred, which was in agreement with the experimental and theoretical observations of diamond film growth.

Kinetic Monte Carlo Simulation of Diamond Film Growth with the Inclusion of Surface Migration

1998 ◽  
Vol 527 ◽  
Author(s):  
Armando Netto ◽  
Michael Frenklach
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Film Growth ◽  
Kinetic Monte Carlo ◽  
Diamond Films ◽  
State Theory ◽  
Diamond Surface ◽  
Diamond Growth ◽  
Gaseous Species ◽  
Surface Migration

ABSTRACTDiamond films are of interest in many practical applications but the technology of producing high-quality, low-cost diamond is still lacking. To reach this goal, it is necessary to understand the mechanism underlying diamond deposition. Most reaction models advanced thus far do not consider surface diffusion, but recent theoretical results, founded on quantum-mechanical calculations and localized kinetic analysis, highlight the critical role that surface migration may play in growth of diamond films. In this paper we report a three-dimensional time-dependent Monte Carlo simulations of diamond growth which consider adsorption, desorption, lattice incorporation, and surface migration. The reaction mechanism includes seven gas-surface, four surface migration, and two surface-only reaction steps. The reaction probabilities are founded on the results of quantum-chemical and transition-state-theory calculations. The kinetic Monte Carlo simulations show that, starting with an ideal {100}-(2×1) reconstructed diamond surface, the model is able to produce a continuous film growth. The smoothness of the growing film and the developing morphology are shown to be influenced by rate parameter values and by deposition conditions such as temperature and gaseous species concentrations.

DYNAMIC SCALING PHENOMENA IN DIAMOND FILM GROWTH

2001 ◽  
Vol 08 (03n04) ◽  
pp. 347-351 ◽  
Author(s):  
M. CATTANI ◽  
M. C. SALVADORI
Keyword(s):  
Chemical Vapor Deposition ◽  
Differential Equations ◽  
Diamond Film ◽  
Vapor Deposition ◽  
Film Growth ◽  
Diamond Films ◽  
Growth Dynamics ◽  
Chemical Vapor ◽  
Dynamic Scaling ◽  
Diamond Film Growth

In this paper we investigate how the growth dynamics of diamond films, synthesized by plasma-enhanced chemical vapor deposition, can be explained within the framework of the Edwards–Wilkinson and Kardar–Parisi–Zhang stochastic differential equations.

Nucleation, Growth, and Microstructure of Nanocrystalline Diamond Films

MRS Bulletin ◽  
1998 ◽  
Vol 23 (9) ◽  
pp. 32-35 ◽  
Author(s):  
Dieter M. Gruen
Keyword(s):  
Atomic Hydrogen ◽  
Film Growth ◽  
Hydrogen Abstraction ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Decisive Role ◽  
Theoretical Work ◽  
Diamond Lattice ◽  
Diamond Surface ◽  
Methyl Radical

It has been generally believed that hydrogen plays a central role in the various processes that have been developed over the years for the chemical vapor deposition (CVD) of diamond films. In particular it has been thought that atomic hydrogen is an absolutely essential ingredient of the vapor from which the films are grown. Typically in diamond CVD, gas mixtures consisting of l-vol% CH3 in 99-vol% H2 have been used in which atomic hydrogen is generated either by thermal decomposition or by collisional processes in a plasma. With a hydrocarbon precursor such as CH3, gas-phase hydrogen-abstraction reactions lead to the generation of the methyl radical CH3, which adsorbs on a carbon radical site also created by hydrogen abstraction from the hydrogen-terminated growing diamond surface. Additional hydrogen-abstraction reactions allow the carbon in the adsorbed methyl radical to form carbon-carbon bonds and thus be incorporated into the diamond lattice. Because graphite is thermodynamically more stable than diamond, the growth of metastable diamond has been thought to require the presence of atomic hydrogen, which has been said to stabilize the diamond lattice and to remove graphitic nuclei when they do form because of the preferential etching or regasification of graphite over diamond. This description of diamond-film growth from hydrocarbon–hydrogen mixtures is of course a very highly condensed version of the detailed experimental and theoretical work that has been carried out in the field over the years. However the predominant conclusion of most of that work is that, particularly in the absence of oxygen and perhaps halogens, atomic hydrogen plays a crucial and decisive role in diamond CVD.

Simulation of Temperature Distribution in HFCVD Diamond Films Growth on the Multitudinous Micro End Mills

2014 ◽  
Vol 1027 ◽  
pp. 163-166
Author(s):  
Bo Song ◽  
Bin Shen ◽  
Xue Lin Lei ◽  
Lei Cheng ◽  
Fang Hong Sun
Keyword(s):  
Temperature Distribution ◽  
Film Growth ◽  
Diamond Films ◽  
Filament Length ◽  
Substrate Distance ◽  
Filament Diameter ◽  
End Mills ◽  
Best Parameter ◽  
Diamond Film Growth

In the process of HFCVD diamond film growth on the multitudinous micro end mills, the uniformity and stability of the temperature distribution have a vital importance on the quality of film. So a new method by using the finite volume is proposed to analyze the importance of different disposition parameters on the uniformity of substrate temperature field. These parameters are filament diameter (d), filament-substrate distance (H), filament separation (S) and filament length (L). The mono-factor method are used to optimize the best parameter combination. The simulation results show that the optimized parameters are d=0.65mm, H=10mm, S=27mm and L=160mm.

Simulations of CVD Diamond Film Growth: 2D Models for the identities and concentrations of gas-phase species adsorbing on the surface

2011 ◽  
Vol 1282 ◽  
Author(s):  
Paul W. May ◽  
Yuri A. Mankelevich
Keyword(s):  
Gas Phase ◽  
Film Growth ◽  
Microwave Plasma ◽  
Plasma Reactor ◽  
Diamond Films ◽  
Diamond Surface ◽  
Diamond Growth ◽  
Process Conditions ◽  
Ultrananocrystalline Diamond ◽  
Single Crystal Diamond

ABSTRACTA prerequisite for modelling the growth of diamond by CVD is knowledge of the identities and concentrations of the gas-phase species which impact upon the growing diamond surface. Two methods have been devised for the estimation of this information, and have been used to determine adsorption rates for CxHy hydrocarbons for process conditions that experimentally produce single-crystal diamond, microcrystalline diamond films, nanocrystalline diamond films and ultrananocrystalline diamond films. Both methods rely on adapting a previously developed model for the gas-phase chemistry occurring in a hot filament or microwave plasma reactor. Using these methods, the concentrations of most of the CxHy radical species, with the exception of CH3, at the surface have been found to be several orders of magnitude smaller than previously believed. In most cases these low concentrations suggest that reactions such as direct insertion of C1Hy (y = 0-2) and/or C2 into surface C–H or C–C bonds can be neglected and that such species do not contribute significantly to the diamond growth process in the reactors under study.

Theoretical Studies of Diamond Surface Chemistry and Diamond-Metal Interfaces

1992 ◽  
Vol 242 ◽  
Author(s):  
W. E. Pickett ◽  
M. R. Pederson ◽  
K. A. Jackson ◽  
S. C. Erwin
Keyword(s):  
Growth Process ◽  
Film Growth ◽  
Chemical Processes ◽  
Schottky Barriers ◽  
Diamond Surface ◽  
Theoretical Studies ◽  
Growth Interface ◽  
Metal Interfaces ◽  
Diamond Film Growth ◽  
Hydrocarbon Vapor

ABSTRACTAdvances in diamond film growth have prompted us to study the interfaces involved in this process: the interface with the substrate, and the growth interface with the ambient hydrocarbon vapor. Carbon chemistry lies at the heart of the properties of both interfaces, and much of the relevant chemistry is not well understood. We report here the energies involved in some idealized chemical processes that may be important in the growth process. Results (Schottky barriers, interface energies) for diamond/metal interfaces are also reported, and the especially unusual diamond/nickel results we have recently obtained are discussed in some detail.

scholarly journals Atomic-Level Investigation ofCHxandC2HxAdsorption onβ-SiC (111) Surface for CVD Diamond Growth from DFT Calculations

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Naichao Chen ◽  
Fanghong Sun
Keyword(s):  
Density Functional ◽  
Hydrogen Adsorption ◽  
Film Growth ◽  
Cvd Diamond ◽  
Unsaturated Hydrocarbon ◽  
Atomic Scale ◽  
Diamond Growth ◽  
Diamond Coatings ◽  
Surface Reconstructions ◽  
Diamond Film Growth

The focus of this paper is on the adsorption of unsaturated hydrocarbon molecules onβ-SiC (111) surfaces during diamond film growth. TheCHxandC2Hxmolecules have been investigated to obtain a specific insight into absorbing diamond processes on the atomic scale. Structural and electronic properties ofCHxandC2Hxadsorption on the Si- and C-terminated surfaces have been studied by first-principles calculations based on density functional theory (DFT). From the calculated energetics and geometries, we find thatC2Hxadsorption on the Si-terminated surfaces has six possible surface reconstructions. For the C-terminated surface, there exist eight possible surface reconstructions. Five surface reconstructions, includingCH2adsorption on the Si- and C-terminated surface, CH–CH2and CH=CH2adsorption on the C-terminated surface, andC2H5adsorption on the Si-terminated surface, have the largest hydrogen adsorption energies and more stability of surface reconstructions. Calculations demonstrate that the Si-terminated surface is energetically more favorable for fabricating CVD diamond coatings than the C-terminated surface.

scholarly journals Effect of Nano-Ni Catalyst on the Growth and Characterization of Diamond Films by HFCVD

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Chien-Chung Teng ◽  
Feng-Chi Ku ◽  
Chien-Min Sung ◽  
Jin-Pei Deng ◽  
Su-Fang Chien ◽  
...  
Keyword(s):  
Amorphous Carbon ◽  
Diamond Film ◽  
Film Growth ◽  
Diamond Films ◽  
Diamond Powder ◽  
Carbon Layer ◽  
Ni Catalyst ◽  
Initial Growth ◽  
Diamond Crystals ◽  
Diamond Film Growth

Four different catalysts, nanodiamond seed, nano-Ni, diamond powder, and mixture of nano-Ni/diamond powder, were used to activate Si wafers for diamond film growth by hot-filament CVD (HFCVD). Diamond crystals were shown to grow directly on both large diamond powder and small nanodiamond seed, but a better crystallinity of diamond film was observed on the ultrasonicated nanodiamond seeded Si substrate. On the other hand, nano-Ni nanocatalysts seem to promote the formation of amorphous carbon but suppress transpolyacetylene (t-PA) phases at the initial growth of diamond films. The subsequent nucleation and growth of diamond crystals on the amorphous carbon layer leads to generation of the spherical diamond particles and clusters prior to coalescence into continuous diamond films based on the CH3 addition mechanism as characterized by XRD, Raman, ATR/FT-IR, XPS, TEM, SEM, and AFM techniques. Moreover, a 36% reduction in surface roughness of diamond film assisted by nano-Ni catalyst is quite significant.

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