Carbon dimer, C{sub 2}, as a growth species for diamond films from methane/hydrogen/argon microwave plasmas

Journal Article · Mon May 01 04:00:00 EDT 1995 · Journal of Vacuum Science and Technology, A

DOI:https://doi.org/10.1116/1.579742· OSTI ID:64965

Gruen, D M; Zuiker, C D; Krauss, A R; Pan, X ^[1]

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1. Materials Science and Chemistry Divisions, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

It was shown recently that nanocrystalline diamond films can be grown using fullerenes as precursors in an argon microwave plasma without the addition of hydrogen or oxygen. Extensive fragmentation of C{sub 60} in the microwave discharge leads to a copious production of the carbon dimer molecule, C{sub 2}, as evidenced by intense Swan-band emission. Here we have investigated hydrogen--methane--argon plasmas and found that high argon fractions ({gt}50%) lead to intense C{sub 2} emission, indicating significant production of C{sub 2} in the plasma. {ital In} {ital situ} measurements of the substrate reflectivity were used to determine the growth rate. A correlation between the C{sub 2} emission intensity and growth rate was observed. These results prompted us to propose a scheme for diamond film growth on the (100)--(2{times}1): H reconstructed diamond surface with C{sub 2} as the growth species. Each surface carbon atom (bonded twice to carbons in the bulk, once to a surface carbon, creating a ``dimer`` and then forming a five-membered ring) is terminated with hydrogen. With C{sub 2} as the growth species, no hydrogen abstraction reactions are required because its very high energy of adsorption (815 kJ/mol C) allows the C{sub 2} molecule to insert directly into the dimer bonds. A second C{sub 2} can form across the adjoining trough. The added carbons then dimerize, forming a new (2{times}1) surface on a new layer with dimer rows orthogonal to the original rows. {copyright} {ital 1995} {ital American} {ital Vacuum} {ital Society}

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 64965
• Journal Information: Journal of Vacuum Science and Technology, A, Journal Name: Journal of Vacuum Science and Technology, A Journal Issue: 3 Vol. 13; ISSN 0734-2101; ISSN JVTAD6
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ADSORPTION
ARGON
CHEMICAL VAPOR DEPOSITION
DIAMONDS
DIMERS
FILMS
HIGH-FREQUENCY DISCHARGES
HYDROGEN
METHANE
PLASMA