CVD of metals using alcohols and metal acetylacetonates, Part II:: Role of solvent and characterization of metal films made by pulsed spray evaporation CVD

Starting from their corresponding acetylacetonate complexes, nickel, copper, and cobalt thin films are deposited in a hydrogen-free atmosphere using CVD. The investigated pulsed spray evaporation (PSE) CVD process uses precursors dissolved in an organic solvent as the feedstock. This paper reports on the major role of the solvent for the growth of metal films. Alcohol solvents such as methanol, ethanol, and n-propanol enabled the growth of metallic films, while nonalcohol solvents such as tetrahydrofuran and n-butyl acrylate failed. Higher alcohols tend to result in higher growth rates; however, they present a limited solubility of the acetylacetonate complexes. Metal films grow, starting at 493 K, on glass and other substrates with no incubation time, and the obtained films, with thicknesses below 30 nm, present a smooth morphology. Phase analysis with X-ray diffraction (XRD) reveals the hexagonal polycrystalline structure of Ni and Co, and the cubic structure of Cu.