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

Abstract

Nitrogen and titanium oxide incorporated diamond-like carbon (DLC) films were deposited by a plasma source ion implantation on silicon wafer and quartz glass. Pure acetylene gas was used as a working gas for plasma. Additional nitrogen and titanium tetraisopropoxide gases were fed into acetylene plasma to prepare nitrogen and titanium oxide incorporated DLC films. The plasma was generated by a radio frequency glow discharge. Ions were accelerated from the plasma by a high-voltage pulse (−20 kV, 100 Hz, 50 μs) applied directly to the substrates. The surface morphology was observed by a scanning electron microscope (SEM) and an atomic force microscope (AFM). The compositional 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 method. The sheet resistivity of the films was measured by a four-point probe method. The results showed that all of the N incorporated and unincorporated films were amorphous and showed typical Raman spectra of DLC films. The XPS and the FT-IR spectra indicated the formation of C–N, CN and CN 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 hardness of the nitrogen and titanium oxide incorporated films decreased with the amount of incorporated species. The sheet resistivity of the films decreased abruptly with increasing nitrogen and titanium oxide contents in the films.