XAFS measurement of gallium in DLC thin film fabricated by FIB-CVD method

We measured the florescence X-ray absorption fine structure (XAFS) spectra of gallium atoms in a diamond-like carbon (DLC) thin film deposited by focused ion beam-chemical vapor deposition (FIB-CVD). Ga K-edge XAFS spectra were measured by monitoring the Ga Kα line in the energy range of 9.9–11.5 keV. The radial distribution function was calculated from the Fourier transform of the extended X-ray absorption fine structure (EXAFS) oscillation that had been obtained by appropriately removing the background and normalization. The peak due to the carbon atoms nearest the central gallium atom was at 1.6 Å. A comparison of the experimentally measured EXAFS oscillation and one calculated by single scattering theory indicated that the coordination number around the central gallium atom and the interatomic distance between the central gallium atom and the carbon atom were ≈ 6.4 and ≈ 2.6 Å, respectively. The interatomic distances for FIB-CVD DLC thin films annealed for 1 h at 200 °C and at 400 °C were the same as the as-deposited film.