Preparation and properties of nitrogen and titanium oxide incorporated diamond-like carbon films by plasma source ion implantation

Nitrogen and titanium oxide incorporated diamond-like carbon (DLC) films we re deposited by a plasma source ion implantation on silicon wafer and quart z glass. Pure acetylene gas was used as a working gas for plasma. Additiona l nitrogen and titanium tetraisopropoxide gases were fed into acetylene pla sma to prepare nitrogen and titanium oxide incorporated DLC films. The plas ma was generated by a radio frequency glow discharge. Ions were accelerated from the plasma by a high-voltage pulse (-20 kV, 100 Hz, 50 mus) applied d irectly to the substrates. The surface morphology was observed by a scannin g electron microscope (SEM) and an atomic force microscope (AFM). The compo sitional and structural characterization of the films was carried out using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The hardness of the films was measured by an indentation meth od. The sheet resistivity of the films was measured by a four-point probe m ethod. The results showed that all of the N incorporated and unincorporated films were amorphous and showed typical Raman spectra of DLC films. The XP S and the FT-IR spectra indicated the formation of C-N, C=N and C equivalen t toN valence bonds. XPS measurement for titanium oxide incorporated films revealed the existence of Ti-C, Ti-O, C-C bonding in the DLC films. The har dness of the nitrogen and titanium oxide incorporated films decreased with the amount of incorporated species. The sheet resistivity of the films decr eased abruptly with increasing nitrogen and titanium oxide contents in the films. (C) 2001 Elsevier Science B.V. All rights reserved.