A first principles study of water dissociation on small copper clusters.

Water dissociation on copper is one of the rate-limiting steps in the water-gas-shift (WGS) reaction. Copper atoms dispersed evenly from freshly made catalyst segregate to form clusters under the WGS operating conditions. Using density functional theory, we have examined water adsorption and dissociation on the smallest stable 3-dimensional copper cluster, Cu(7).

Interaction of copper organometallic precursors with barrier layers of Ti, Ta and W and their nitrides: a first-principles molecular dynamics study.

Processes for the deposition of copper films on transition metal barrier layers by means CVD using organometallic precursors are often found to lead to poor adhesion characteristics of the grown film. By means of first-principles molecular dynamics simulations, we show that the source of the problem is the strong reactivity of the surfaces toward the precursors, which decompose spontaneously upon contact with the surface leading to contamination of the interface. Our simulations consider Ti, Ta, and W as barrier layers, and Cu(hfac)-(tmvs) as precursor.

First-principles analyses and predictions on the reactivity of barrier layers of Ta and TaN toward organometallic precursors for deposition of copper films.

We present theoretical studies based on first-principles density functional theory calculations on the mechanisms of chemical vapor deposition of Cu-hexafluoracetylacetonato-trimethylvinylsilane (Cu(hfac)(tmvs)) on tantalum surfaces. This process has been used in the past to grow copper films via a disproportionation reaction and was found to exhibit adhesion problems. We show that the Ta surfaces are highly reactive and that the organic ligands in a copper precursor would undergo spontaneous decomposition upon contact with the Ta substrates.