58 research outputs found
Cobalt(I) olefin complexes:precursors for metal-organic chemical vapor deposition of high purity cobalt metal thin films
We
report the synthesis and characterization of a family of organometallic
cobaltÂ(I) metal precursors based around cyclopentadienyl and diene
ligands. The molecular structures of the complexes cyclopentadienylâcobaltÂ(I)
diolefin complexes are described, as determined by single-crystal
X-ray diffraction analysis. Thermogravimetric analysis and thermal
stability studies of the complexes highlighted the isoprene, dimethyl
butadiene, and cyclohexadiene derivatives [(C<sub>5</sub>H<sub>5</sub>)ÂCoÂ(η<sup>4</sup>-CH<sub>2</sub>CHCÂ(Me)ÂCH<sub>2</sub>)] (<b>1</b>), [(C<sub>5</sub>H<sub>5</sub>)ÂCoÂ(η<sup>4</sup>-CH<sub>2</sub>CÂ(Me)ÂCÂ(Me)ÂCH<sub>2</sub>)] (<b>2</b>), and [(C<sub>5</sub>H<sub>5</sub>)ÂCoÂ(η<sup>4</sup>-C<sub>6</sub>H<sub>8</sub>)] (<b>4</b>) as possible
cobalt metal organic chemical vapor deposition (MOCVD) precursors.
Atmospheric pressure MOCVD was employed using precursor <b>1</b>, to synthesize thin films of metallic cobalt on silicon substrates
under an atmosphere (760 torr) of hydrogen (H<sub>2</sub>). Analysis
of the thin films deposited at substrate temperatures of 325, 350,
375, and 400 °C, respectively, by scanning electron microscopy
and atomic force microscopy reveal temperature-dependent growth features.
Films grown at these temperatures are continuous, pinhole-free, and
can be seen to be composed of hexagonal particles clearly visible
in the electron micrograph. Powder X-ray diffraction and X-ray photoelectron
spectroscopy all show the films to be highly crystalline, high-purity
metallic cobalt. Raman spectroscopy was unable to detect the presence
of cobalt silicides at the substrate/thin film interface
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