CVD of Metals Using Alcohols and Metal Acetylacetonates, Part I: Optimization of Process Parameters and Electrical Characterization of Synthesized Films

Abstract

A new successful strategy is developed for the production of Ni, Cu, and Co films using commercially available metal acetylacetonates as precursors. Pulsed spray evaporation (PSE) CVD is applied utilizing only alcohols as solvents and reducing agents. The efficiency of the process, with respect to controlling parameters such as pulse width, pulsing frequency, carrier gas flow rate, and concentration of the precursors in the feedstock, is optimized. The growth of metal films as a function of substrate temperature, deposition pressure, and duration of deposition, is examined. Results demonstrate that the metal films grow on various substrates, including glass and SiC, without any incubation time and do not need a seed layer. Resulting resistivities are close to those of the bulk materials for Ni and Cu films, while a value of 150 lX cm, which improves upon annealing, is measured for Co films.

CVD of Metals Using Alcohols and Metal Acetylacetonates, Part II: Role of Solvent and Characterization of Metal Films Made by Pulsed Spray Evaporation CVD

“…The schematic set-up of the PSECVD apparatus for the growth of metal films, as well as the operational procedures to obtain them, has been described elsewhere [26]. Except for the investigations of the role that the solvents play in the growth of metal films at various temperatures, experiments were carried out for Ni, Co, and Cu films at a substrate temperature of 523, 600, and 673 K, respectively.…”

“…The relatively high resistivity of cobalt films was also observed despite the use of a supplementary flow of hydrogen to enhance the reduction. [26] …”

“…Depositions were carried via PSECVD using the process parameters defined in the optimization study, viz, a pulse width of 25 ms, a pulsing frequency of 1 Hz, 5 mM concentration of precursor feedstock, 45 mbar deposition pressure, and 1 slm of nitrogen carrier gas. [26] Figure 1 represents the temperature-dependent growth rate of Ni films on glass using ethanol or n-butyl acrylate as solvents. These results show clearly that nickel films grow only when ethanol was used as the solvent, and that no appreciable growth occurs with n-butyl acrylate.…”

“…The present paper is the second in a series which discusses a novel strategy for metal film production with the exclusive use of alcohols as reducing agents and metal acetylacetonates as the precursors. [25,26] The first part, devoted to the successful demonstration of Ni, Cu, and Co films in PSECVD, [26] has presented the optimization of the process itself as a function of delivery and deposition parameters. Here, the use of cost-effective, metal-organic complexes like acetylacetonates, while avoiding hydrogen addition, makes the technology simple, inexpensive, poses less severe safety constraints, and enables the recycling of the reducing agent.…”

Innovative CNT-based composite coatings for the stray light reduction

“…Adsorbed ethanol reacts with surface cobalt acetylacetonate (Co(acac) 2 ) above 220 °C to form coatings of metal, carbide or a mixture thereof depending on the temperature used. [11][12][13][14][15] Based on this observation, a proprietary approach was implemented to grow decorated non-aligned CNTs (Figure 1) at 350-450 °C using either a sequential or simultaneous surface reactions. The growth temperature has a substantial impact on the growth rate of the CNT-based nanocomposites.…”