abstract
A method for the growth of Diamond/WC bilayers in a single process is presented with interest for the production of well adhered electrical contacts to diamond surfaces. This process uses a common hot filament chemical vapor deposition (HFCVD) reactor, with W filaments as the source for the deposition of the metallic layer, and H-2 and CH4 gasses as the reactive species for the diamond growth. The method begins by vaporizing the filaments in vacuum for a few minutes, followed by the chemical vapor deposition of diamond. The results have shown that by varying the filament vaporization time and temperature it is possible to deposit on the Si substrate tungsten containing coatings of different thicknesses. The process starts by vaporization of naturally oxidized filaments and deposition on the substrate. Afterward, the tungsten oxide carburises to W2C and WC phases. The CVD growth of the diamond layers on these carbide layers is dependent on the CH4/H-2 ratios, system pressure and substrate temperature. The seeding of the Si substrates with diamond powder before the CVD process, guarantees that diamond is nucleated inside the metallic carbide layer, anchoring the top nanocrystalline diamond layer. (C) 2011 Elsevier B.V. All rights reserved.
keywords
CHEMICAL-VAPOR-DEPOSITION; NANOCRYSTALLINE DIAMOND; ULTRANANOCRYSTALLINE DIAMOND; RAMAN-SPECTROSCOPY; AMORPHOUS-CARBON; FILMS; TUNGSTEN; NUCLEATION; CONTACTS; TEMPERATURE
subject category
Materials Science; Physics
authors
Neto, MA; Silva, EL; Fernandes, AJS; Oliveira, FJ; Silva, RF
our authors
Filipe José Alves de Oliveira
Principal Researcher
Miguel Ângelo da Costa Neto
Researcher
Rui Ramos Ferreira e Silva
Associate Professoracknowledgements
This work was supported by project PTDC/CTM-MET/113645/2009, funded by FEDER through COMPETE programmme - Operacional Factors for Competitivity and by national funds through FCT - Portuguese Science and Technology Foundation.; M.A. Neto and E.L. Silva would like to acknowledge, respectively, the grants SFRH/BPD/45610/2008 and SFRH/BD/61675/2009 from FCT.