Deposition of polycrystalline diamonds in a d.c. plasma jet of Ar/H2/CH4

Vilotijević, Miroljub; Dimitrijevic, Stevan; Randjelovic, Igor

doi:10.1007/bf00506330

Cited by 1 publication

(1 citation statement)

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“…[1][2][3][4][5][6][7][8][9][10][11] The particular application addressed here employs an Ar/ H 2 plasma, in the form of a dc arc jet, for methane activation and subsequent chemical vapor deposition ͑CVD͒ of polycrystalline diamond. [12][13][14][15][16][17][18][19][20] For completeness, we note that microwave-activated hydrocarbon/H 2 / Ar gas mixtures find even more widespread use for growing both CVD of single crystal, 21 microcrystalline, 22 and ͑at very low H 2 partial pressures͒ ultrananocrystalline diamond films. 23 In this and a subsequent article 24 we present a detailed and comprehensive analysis of the gas-phase chemistry underpinning the growth of polycrystalline diamond in a dc arc jet reactor operating with a CH 4 /H 2 / Ar mixture, involving a͒ Permanent address: Department of Applied Physics, Eindhoven University of Technology, P.O.…”

Section: Introductionmentioning

confidence: 99%

Measurement and modeling of a diamond deposition reactor: Hydrogen atom and electron number densities in an Ar∕H2 arc jet discharge

Rennick

Engeln

Smith

et al. 2005

Journal of Applied Physics

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Please check the document version of this publication:• A submitted manuscript is the version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal.If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement: A combination of experiment ͓optical emission and cavity ring-down spectroscopy ͑CRDS͒ of electronically excited H atoms͔ and two-dimensional ͑2D͒ modeling has enabled a uniquely detailed characterization of the key properties of the Ar/ H 2 plasma within a ഛ10-kW, twin-nozzle dc arc jet reactor. The modeling provides a detailed description of the initial conditions in the primary torch head and of the subsequent expansion of the plasma into the lower pressure reactor chamber, where it forms a cylindrical plume of activated gas comprising mainly of Ar, Ar + , H, ArH + , and free electrons. Subsequent reactions lead to the formation of H 2 and electronically excited atoms, including H͑n =2͒ and H͑n =3͒ that radiate photons, giving the plume its characteristic intense emission. The modeling successfully reproduces the measured spatial distributions of H͑n Ͼ 1͒ atoms, and their variation with H 2 flow rate, F H 2 0 . Computed H͑n =2͒ number densities show near-quantitative agreement with CRDS measurements of H͑n =2͒ absorption via the Balmer-␤ transition, successfully capturing the observed decrease in H͑n =2͒ density with increased F H 2 0 . Stark broadening of the Balmer-␤ transition depends upon the local electron density in close proximity to the H͑n =2͒ atoms. The modeling reveals that, at low F H 2 0 , the maxima in the electron and H͑n =2͒ atom distributions occur in different spatial regions of the plume; direct analysis of the Stark broadening of the Balmer-␤ line would thus lead to an underestimate of the peak electron density. The present study highlights the necessity of careful interco...

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