Analysis of the total carbon deposition during the bias enhanced nucleation of diamond on Ir/SrTiO3 (001) using 13C-methane

Carbon deposition during bias enhanced nucleation (BEN) of diamond on Ir/SrTiO3 (001) was measured by elastic recoil detection (ERD) analysis using C-13-methane in the process gas. High resolution optical emission spectra (OES) of CH emission lines from the gas phase as well as Raman spectra of deposited diamond films showed the high isotopic purity of the reaction gas. During the biasing step a carbon coverage of approximately 1 x 10(16) cm(-2) equivalent to a 0.6-nm-thick diamond layer was deposited at the surface after 45 min. Its thickness only increased slowly for longer biasing. A similar carbon enrichment was also found at the iridium/SrTiO3 interface. After the nucleation step, nanometer-size particles of very uniform height were found at the iridium surface. Their integral volume was more than an order of magnitude lower than the total volume of the carbon layer present at the surface after BEN. Our experiments indicate that most of the carbon is continuously distributed over the surface which allows to sketch a rough image of the processes occurring during BEN on iridium. (C) 2002 Elsevier Science B.V. All rights reserved.