Growth and fractal scaling nature of copper thin films on TiN surface by metal organic chemical vapor deposition from hexafluoroacethylacetonate Cu(I) vinyltrimethylsilane

Abstract

The initial stage of growth and fractal scaling nature of copper (Cu) films, deposited by metal organic chemical vapor deposition on TiN substrate using hexafluoroacethylacetonate Cu(I) vinyltrimethylsilane precursor, was investigated by means of Auger electron spectroscopy, atomic force microscopy (AFM), x-ray diffraction, transmission electron microscopy, and scanning electron microscopy (SEM). Cu films were deposited in the surface reaction controlled regime (<200 °C) onto a columnar structure TiN substrate and discontinuous island growth was observed due to oxygen contamination of the TiN surface. Preferred orientation of the deposited Cu film changed as a function of the deposition time and coverage. The roughness exponent (α) and lateral correlation length (ξ) of Cu films grown under different growth stages were studied. From AFM measurement, it was found that the roughness exponent increased with increasing deposition time and the lateral correlation length also increased as the grains coalesced, which was also compared with SEM images. For island growth mode at the early stage of growth, α was below 0.65 and it saturated at 0.75 for the continuous growth mode.