Experimental and kinetic studies of C–H–O plasmas for polycrystalline and nano-smooth diamond deposition

Gries, Thomas; Persis, S. de; Vandenbulcke, L.; Met, C.; Delfau, Jean‐Louis

doi:10.1016/j.diamond.2009.01.032

Cited by 8 publications

(5 citation statements)

References 14 publications

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“…These smooth fine-grained diamond (SFGD) coatings are described in terms of the ratio of sp 2 - to sp 3 -hybridized carbons. This important parameter influences the structure and intrinsic properties of the coatings (surface roughness, hardness, Young’s modulus, and residual stresses) and is correlated with the plasma-assisted CVD process through the formation of different concentrations of the gaseous precursors in the plasma. , As shown in Table , fairly good SFGD coatings with high purity and low roughness can be deposited, especially when the CH 4 /CO 2 ratio is low. Characteristics of a polycrystalline diamond coating are also reported in this table for comparison.…”

Section: Resultsmentioning

confidence: 99%

Friction of Diamond in the Presence of Water Vapor and Hydrogen Gas. Coupling Gas-Phase Lubrication and First-Principles Studies

et al. 2012

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Nanocrystalline diamond (NCD) has attracted much attention in recent years because of improvements in growth methodologies that have provided increases in both film thickness and growth rate, while preserving the outstanding mechanical properties of diamond material. We provide here some evidence, based on combined experimental and first-principles analyses, that ultralow friction of nanocrystalline diamond in the presence of water vapor is associated with OH and H passivation of sliding surfaces, resulting from the dissociative adsorption of H2O molecules. The presence of these adsorbates (OH and H fragments) keeps the surfaces far apart preventing the formation of covalent bonds across the interface. H-passivated surfaces, resulting from the dissociative adsorption of H2 molecules, appears to be more efficient in further reducing friction than OH-terminated surfaces.

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Section: Resultsmentioning

confidence: 99%

Friction of Diamond in the Presence of Water Vapor and Hydrogen Gas. Coupling Gas-Phase Lubrication and First-Principles Studies

et al. 2012

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“…The properties of these NCD coatings (surface roughness, hardness, Young's modulus) are correlated to the MW-PACVD process through the concentrations of the gaseous precursors used in the plasma [27][28][29]. For this study, a fairly good quality Table 1).…”

Section: Characterisation Of Pristine Ncd Coatingsmentioning

confidence: 98%

Energy filtering transmission electron microscopy and atomistic simulations of tribo-induced hybridization change of nanocrystalline diamond coating

Matta

Vacher

Le-Mogne

et al. 2015

Carbon

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“…Even a small excess of CH 4 over CO 2 resulted in noticeably poorer quality material. Vandenbulcke and co-workers , have reported diagnostic and modeling studies of low pressure MW-activated C/H/O gas mixtures and of the polycrystalline diamond derived there from. For completeness, we note that the possible benefits of adding trace quantities of oxygen to C/H process gas mixtures (as O 2 or as another O containing species like CO or CO 2 ) in order to reduce nitrogen incorporation and cracking in CVD grown single crystal diamond, , and as a means of inhibiting [110] growth in heavily B-doped diamond have also been explored.…”

Section: Introductionmentioning

confidence: 99%

Exploring the Plasma Chemistry in Microwave Chemical Vapor Deposition of Diamond from C/H/O Gas Mixtures

Kelly¹,

Richley²,

Western³

et al. 2012

J. Phys. Chem. A

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Microwave (MW)-activated CH(4)/CO(2)/H(2) gas mixtures operating under conditions relevant to diamond chemical vapor deposition (i.e., X(C/Σ) = X(elem)(C)/(X(elem)(C) + X(elem)(O)) ≈ 0.5, H(2) mole fraction = 0.3, pressure, p = 150 Torr, and input power, P = 1 kW) have been explored in detail by a combination of spatially resolved absorption measurements (of CH, C(2)(a), and OH radicals and H(n = 2) atoms) within the hot plasma region and companion 2-dimensional modeling of the plasma. CO and H(2) are identified as the dominant species in the plasma core. The lower thermal conductivity of such a mixture (cf. the H(2)-rich plasmas used in most diamond chemical vapor deposition) accounts for the finding that CH(4)/CO(2)/H(2) plasmas can yield similar maximal gas temperatures and diamond growth rates at lower input powers than traditional CH(4)/H(2) plasmas. The plasma chemistry and composition is seen to switch upon changing from oxygen-rich (X(C/Σ) < 0.5) to carbon-rich (X(C/Σ) > 0.5) source gas mixtures and, by comparing CH(4)/CO(2)/H(2) (X(C/Σ) = 0.5) and CO/H(2) plasmas, to be sensitive to the choice of source gas (by virtue of the different prevailing gas activation mechanisms), in contrast to C/H process gas mixtures. CH(3) radicals are identified as the most abundant C(1)H(x) [x = 0-3] species near the growing diamond surface within the process window for successful diamond growth (X(C/Σ) ≈ 0.5-0.54) identified by Bachmann et al. (Diamond Relat. Mater.1991, 1, 1). This, and the findings of similar maximal gas temperatures (T(gas) ~2800-3000 K) and H atom mole fractions (X(H)~5-10%) to those found in MW-activated C/H plasmas, points to the prevalence of similar CH(3) radical based diamond growth mechanisms in both C/H and C/H/O plasmas.

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Experimental and kinetic studies of C–H–O plasmas for polycrystalline and nano-smooth diamond deposition

Cited by 8 publications

References 14 publications

Friction of Diamond in the Presence of Water Vapor and Hydrogen Gas. Coupling Gas-Phase Lubrication and First-Principles Studies

Friction of Diamond in the Presence of Water Vapor and Hydrogen Gas. Coupling Gas-Phase Lubrication and First-Principles Studies

Energy filtering transmission electron microscopy and atomistic simulations of tribo-induced hybridization change of nanocrystalline diamond coating

Exploring the Plasma Chemistry in Microwave Chemical Vapor Deposition of Diamond from C/H/O Gas Mixtures

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