Spectroscopic characterization of TiCx films produced by pulsed laser deposition in CH4 environments

Titanium carbide (TiCx) thin films were grown on (1 0 0)-Si substrates by a pulsed laser deposition (PLD) method using a Ti target in methane gas. The films are characterized in situ by Auger (AES), electron energy loss (EELS) and X-ray photoelectron spectroscopies (XPS). It was found that the reaction between the ablated Ti species and CH4 in the plasma plume influenced the C:Ti ratio. XPS numerical fitting for the C 1s transition revealed three Gaussians components. The main component, binding energy of 282.8 eV, is assigned to C making bonds with Ti, like in stoichiometric TiC. The second component, binding energy of 284.9 eV, is assigned to C–C bonds. A third component is found for films deposited at pressures higher than 25 mTorr at 286.5 eV. A post-deposition thermal treatment demonstrates that the Ti–C and C–C peaks are very stable, whereas, the third peak tends to decrease for temperatures higher than 200 8C. It is assumed that this last component is due to carbonyl complexes remnant in films. Finally, it can be concluded that the titanium carbide films processed by PLD is a chemically inhomogeneous material; mostly composed of sub-stoichiometric TiC and particulates of segregated carbon. # 2004 Elsevier B.V. All rights reserved.