Structure and composition of hydrogenated TixCy thin films prepared by reactive sputtering

Abstract

Thin films of hydrogenated titanium carbide are prepared by reactive magnetron direct current sputtering in mixed atmospheres of argon and methane or argon and acetylene. The deposition process is followed on line by optical emission spectroscopy. The films are characterized by various techniques: scanning electron microscopy, transmission electron diffraction and microscopy, x-ray diffraction, Auger electron spectroscopy, x-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The influence of the gas phase composition and the current density on the structure and composition of the films is examined. The morphology and crystallinity of the deposits are strongly dependent on the carbon content in the films. The presence of an amorphous carbon phase results in a decrease of the TiC grain size. The proportion of Ti–C bonds in the films is correlated to the decomposition of the carbon precursor in the discharge, as shown by optical emission spectrometry, and to the composition of the target surface in these conditions. This is especially strong in the case of C2H2–Ar mixtures. A comparison of the two carbon precursors is presented.