Understanding the chemical vapor deposition of diamond: recent progress

Butler, James E.; Mankelevich, Yu. A.; Cheesman, Andrew; Ma, Jie; Ashfold, Michael N. R.

doi:10.1088/0953-8984/21/36/364201

Cited by 183 publications

(171 citation statements)

References 129 publications

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“…The unsaturated CH x (x < 3) species studied here can also add to radical sites on the surface. These radical-radical recombination steps presumably do not involve an energy barrier, as found, experimentally, for a range of gas phase alkyl recombination reactions 16 and, theoretically, in previous studies of CH 3 addition to radical sites on the diamond surface. 12 Such addition processes have not been studied in the present work, however.…”

Section: Introductionsupporting

confidence: 75%

“…3 3 CH 2 radicals can also abstract the H atom from a surface C-H bond. B3LYP/6-311g(d,p)//B3LYP/6-31g(d) calculations on the QM model system, including zero point correction calculated at the B3LYP/ 6-31g(d) level, show that the energy barrier for abstraction of an HC1-type H atom by an incident 3 CH 2 radical is only 14.3 kJ mol -1 .…”

Section: //B3lyp/6-31g(d) Energies (Including Zero Point Corrections mentioning

confidence: 99%

“…The latter difference manifests itself clearly in the hydrocarbon radical densities, however. Under MCD growth conditions, CH 3 radicals account for >99% of the total C 1 H x (x ) 0-3) radical density at z ) 0.5 mm above the center of the substrate surface whereas, under UNCD growth conditions, CH 3 radicals are predicted to account for only ∼26% of ∑ x)0 3 [CH x ] and to be outnumbered by C atoms (by more than a factor of 2) and by heavier radical species like C 2 H and C 3 .…”

Section: Introductionmentioning

confidence: 99%

“…12 Such addition processes have not been studied in the present work, however. Under MCD growth conditions, at least, the low densities of such CH x (x < 3) species near the growing diamond surface (relative to that of CH 3 ) suggests that their addition reactions are unlikely to make a significant contribution to diamond growth.…”

Section: Introductionmentioning

confidence: 99%

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On the Role of Carbon Radical Insertion Reactions in the Growth of Diamond by Chemical Vapor Deposition Methods

2009

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radicals, into C-H and C-C bonds on a 2 × 1 reconstructed, H-terminated diamond {100} surface have been explored using both quantum mechanical (density functional theory) and hybrid quantum mechanical/molecular mechanical (QM/MM) methods. Both sets of calculations return minimum energy pathways for inserting a C atom, or a CH(X), C 2 (X), or CH 2 (a) radical into a surface C-H bond that are essentially barrierless, whereas the barriers to inserting any of the investigated species into a surface C-C bond are prohibitively large. Reactivity at the diamond surface thus parallels behavior noted previously with alkanes, whereby reactant species that present both a filled σ orbital and an empty p(π) orbital insert readily into C-H bonds. Most carbon atoms on the growing diamond surface under typical chemical vapor deposition conditions are H-terminated. The present calculations thus suggest that insertion reactions, particularly reactions involving C( 3 P) atoms, could make a significant contribution to the renucleation and growth of ultrananocrystalline diamond (UNCD) films.

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Section: Introductionsupporting

confidence: 75%

Section: //B3lyp/6-31g(d) Energies (Including Zero Point Corrections mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the Role of Carbon Radical Insertion Reactions in the Growth of Diamond by Chemical Vapor Deposition Methods

2009

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“…A scheme of the PE-CVD process of nanostructured diamond can be found in figure 2. It is believed that atomic hydrogen is the drive behind all the gas phase (plasma) chemistry during the deposition of diamond thin films [53,54]. In the hot regions, atomic hydrogen abstracts hydrogen atoms from methane molecules, creating radicals which can recombine into C x H y species containing two or more carbon atoms.…”

Section: Modeling the Plasma Chemistry For The Growth Of Nanostructurmentioning

confidence: 99%

Computer modelling of the plasma chemistry and plasma-based growth mechanisms for nanostructured materials

Bogaerts¹,

Eckert²,

Mao³

et al. 2011

J. Phys. D: Appl. Phys.

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In this review paper, an overview is given of different modeling efforts for plasmas used for the formation and growth of nanostructured materials. This includes both the plasma chemistry, providing information on the precursors for nanostructure formation, as well as the growth processes itself. We limit ourselves to carbon (and silicon) nanostructures. Examples of the plasma modeling comprise nanoparticle formation in silane and hydrocarbon plasmas, as well as the plasma chemistry giving rise to carbon nanostructure formation, such as (ultra)nanocrystalline diamond ((U)NCD) and carbon nanotubes (CNTs). The second part of the paper deals with the simulation of the (plasma-based) growth mechanisms of the same carbon nanostructures, i.e., (U)NCD and CNTs, both by mechanistic modeling and detailed atomistic simulations. IntroductionLow temperature plasmas are playing an increasingly important role for the formation and growth of nanostructures and nanostructured materials (e.g., [1][2][3][4][5][6][7]). To improve the performance of these plasma growth processes, a good insight is desired in the plasma and in the interaction with the growing nanostructures. This insight can be obtained by experimental research, but the latter is not always straightforward, in view of the small dimensions of the nanomaterials and the possible disturbance of the plasma characteristics, e.g., when introducing a probe. Therefore, computer simulations can be very useful to assist in the experimental developments.In the present paper, we will give an overview of different modeling efforts that have been presented in the literature for plasmas used for nanostructure formation. This includes two different aspects. First, a thorough understanding of the plasma behavior is needed. This comprises background gas flow and heating (i.e., fluid dynamics), gas breakdown, transport and heating of the electrons and the so-called heavy particles, as well as the plasma chemistry, i.e., creation and destruction of the various plasma species by chemical reactions. Modeling of the plasma chemistry can give indications on which species are important precursors for the growth of nanostructured materials and how the plasma operating conditions can be tuned to optimize the growth process. Therefore, in this paper we will mainly focus on the plasma chemistry modeling. Several plasma modeling approaches exist in literature, such as analytical models, zero-dimensional (0D) chemical kinetics simulations, fluid models (describing the chemical kinetics as well as fluid dynamics), solving the Boltzmann transport equation, Monte Carlo (MC) and particle-in-cell (PIC)-MC simulations, as well as hybrid methods, combining the above (e.g., MC + fluid) models. For describing the plasma chemistry, the 0D chemical kinetics approach is often applied, as it can take into account a large number of different species and reactions without too much computational effort. However, it assumes a spatially uniform plasma composition and does not consider transport of the plasm...

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