Study of different forms of carbon by analytical electron microscopy

Polycrystalline diamond films grown on non-scratched Si substrates by the H ot Filament-Chemical Vapor Deposition (HF-CVD) were studied by Parallel EEL S (PEELS) and Extended Electron Energy Loss Fine Structure Spectroscopy (EX EELFS) techniques. PEELS spectra of diamond films were compared with those obtained for natural diamond. These spectra show that the plasmon and carbo n K-edge main features are almost indistinguishable (in position and shapes ) in both, natural and our HF-CVD diamond films. The radial distribution fu nction around the carbon atoms was obtained through the Fourier transform o f the extended fine structure located in a 300 eV range beyond the carbon K -edge in the energy loss spectra. The values obtained for the C-C distances are very close (within 0.003 nm) to those of the natural cubic diamond str ucture. These results were accomplished by analyzing the respective X-Ray d iffraction pattern (XRD) of the diamond films. This study confirms the good quality of the diamond films produced by our experimental technique. (C) 1 999 Elsevier Science B.V. All rights reserved.