Microwave plasma-assisted chemical vapor deposition of microcrystalline diamond films <i>via</i> graphite etching under different hydrogen flow rates

Yao, Kaili; Dai, Bing; Tan, Xuezhi; Yang, Lei; Zhao, Junhong; Ralchenko, V.G.; Shu, Guoyang; Liu, Kang; Han, Jiecai; Zhu, Jiaqi

doi:10.1039/c9ce00120d

Cited by 11 publications

(5 citation statements)

References 37 publications

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“…With little or no Ar addition, the mainly H 2 atmosphere produced diamond powder with well‐defined, micro‐scale facetted crystallites. [ 32 ] This is consistent with what is known [ 33,34 ] about the mechanisms for the growth of diamond via CVD, which relies on a high ratio of H atoms to carbon radical species (H: C x H y ) near the surface to deposit sp 3 diamond rather than sp 2 graphitic carbon. In our CVD system, the graphite disks act as the carbon source, which is etched by H atoms to form the gas‐phase CH 3 radicals responsible for diamond growth.…”

Section: Resultssupporting

confidence: 88%

“…Aggregated diamond powders were grown using a microwave plasma CVD reactor. [ 32 ] The gas mixture consisted of hydrogen and argon (both 99.999%) with a total gas flow rate of 200 sccm. Diamond powders with different properties were made by varying the Ar flow rate as follows: 0, 4, 10, 20, 40, and 100 sccm, equivalent to 0%, 2%, 5%, 10%, 20%, and 50% of the total flow rate.…”

Section: Methodsmentioning

confidence: 99%

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Hydrophobicity and Adhesion of Aggregated Diamond Particles

Yao

Dai

May

et al. 2020

Physica Status Solidi (a)

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Diamond powders with high hydrophobicity are prepared by etching graphite plates using a hydrogen/argon (H2/Ar) plasma. The morphology and size of the diamond powders are found to vary with the proportion of Ar in H2 from 0% to 50%. Wettability is measured using water contact angle (WCA) measurements giving values between 129.7° and 146.9°. The high hydrophobicity can be ascribed to the aggregated structure of the as‐grown diamond powders. To check this assumption, the aggregated diamond powders are separated into individual particles by mechanical grinding; then, the WCAs of separated as‐grown diamond powders and commercial dispersed diamond powders are compared. The separated diamond surfaces show the lower WCAs of 99.68° and 96.96°. The surface of the aggregated diamond powders also exhibits high adhesion to water. The diamond surface grown in 2% Ar suspends 40 μL of water under a tilt angle of 180°. Such aggregated diamond powders are promising for no‐loss liquid transportation.

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Section: Resultssupporting

confidence: 88%

Section: Methodsmentioning

confidence: 99%

Hydrophobicity and Adhesion of Aggregated Diamond Particles

Yao

Dai

May

et al. 2020

Physica Status Solidi (a)

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“…Figure 2a shows the XRD patterns of the PBDD films. The peaks at 69.2 • and 69.4 • correspond to Si (004) and Si (100), respectively [30], and the peak at 61.7 • corresponds to SiC. During the growth of the PBDD film, adamantane or carbon species firstly react with the Si surface, forming an SiC interlayer between the PBDD film and the Si substrate [31].…”

Section: Resultsmentioning

confidence: 99%

“…During the growth of the PBDD film, adamantane or carbon species firstly react with the Si surface, forming an SiC interlayer between the PBDD film and the Si substrate [31]. All PBDD films exhibit the same diamond phases with three orientations: (111), (220), and (311) [30]. The (111) peak at 43.9 • exhibits the highest intensity, indicating the existence of the (111) preferred orientation.…”

Section: Resultsmentioning

confidence: 99%

Effect of Boron Doping Concentration on the Wettability and Surface Free Energy of Polycrystalline Boron-Doped Diamond Film

Wang

Yuan

et al. 2023

Coatings

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The wettability and surface free energy of diamonds are crucial for their applications. In this study, polycrystalline boron-doped diamond (PBDD) films with different boron doping concentrations were prepared, and the effect of the boron doping concentration on the wettability and surface free energy (SFE) of the film was investigated. The SFEs of the PBDD films were investigated by employing the surface tension component approach and the equation-of-state approach. The investigation suggested that the alternative formulation of Berthelot’s rule, the Lifshitz-van der Waals/acid-base (van Oss) approach, and the Owens-Wendt-Kaelble approach were suitable for estimating the SFEs of PBDD films, whereas the Fowkes approach, Berthelot’s (geometric mean) combining rule, and Antonow’s rule could not provide reliable results. Results showed that the SFEs of PBDD films increased with increasing boron doping concentration, and the SFEs were 43.26–49.66 mJ/m2 (Owens-Wendt-Kaelble approach), 42.89–52.26 mJ/m2 (Lifshitz-van der Waals/acid-base), and 44.38–48.73 mJ/m2 (alternative formulation of Berthelot’s rule). This study also provides a reference for the application of empirical and physics-based semi-empirical approaches to SFE estimation.

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“…In the process of diamond growth by chemical vapor deposition (CVD), the chemical reaction of atomic hydrogen on the surface has a very important influence on the growth rate and surface quality. [1][2][3][4][5] Under adverse experimental conditions, the quality of grown diamond can be affected by the presence of graphite and amorphous carbon defects. In order to obtain a high quality diamond film without graphite and amorphous carbon, the proportion of hydrogen flow in the reaction gas (hydrogen/methane) is usually increased to more than 95%.…”

Section: Introductionmentioning

confidence: 99%

The Etching Mechanisms of Diamond, Graphite, and Amorphous Carbon by Hydrogen Plasma: A Reactive Molecular Dynamics Study

Zhang

et al. 2023

Advcd Theory and Sims

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Understanding how hydrogen plasma etches various potential products during the diamond growth process can contribute to improving the knowledge of diamond growth. However, due to the absence of an in situ characterization technique during the etching process, the complex chemical reactions involved in the process obscure the atomic‐scale etching mechanisms. In this paper, the etching mechanisms of diamond (001), graphite (0001), and amorphous carbon substrates irradiated by hydrogen plasmas are investigated and compared using molecular dynamics simulations based on ReaxFF. When the incident energy of H atoms is 1 eV, the rate of carbon loss from graphite and amorphous carbon are far higher than that from diamond. As the incident energy of H atoms increases, the etching rate of diamond shows a slow increase, while the etching rates of amorphous carbon and graphite exhibit more significant increases. It can be concluded that the etching rate of diamond is significantly lower than that of graphite and amorphous carbon under H plasma. In the Chemical Vapor Deposition (CVD) process of diamond growth, the generated graphite and amorphous carbon are rapidly etched, leaving only diamond. This offers a plausible explanation for the growth mechanism of diamond through CVD.

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Microwave plasma-assisted chemical vapor deposition of microcrystalline diamond films via graphite etching under different hydrogen flow rates

Abstract: The growth of microcrystalline diamond films with different hydrogen flow rates via etching graphite as the carbon source was studied.

Cited by 11 publications

References 37 publications

Hydrophobicity and Adhesion of Aggregated Diamond Particles

Hydrophobicity and Adhesion of Aggregated Diamond Particles

Effect of Boron Doping Concentration on the Wettability and Surface Free Energy of Polycrystalline Boron-Doped Diamond Film

The Etching Mechanisms of Diamond, Graphite, and Amorphous Carbon by Hydrogen Plasma: A Reactive Molecular Dynamics Study

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