The thermal atomic layer deposition (ALD) of copper oxide films from the nonfluorinated yet liquid precursor bis(tri- n -butylphosphane)copper(I)acetylacetonate, [(Bnu3normalP)C2normalu(acac)] , and wet O2 on Ta, TaN, Ru, and SinormalO2 substrates at temperatures of <160°C is reported. Typical temperature-independent growth was observed at least up to 125°C with a growth-per-cycle of ∼0.1Å for the metallic substrates and an ALD window extending down to 100°C for Ru. On SinormalO2 and TaN, the ALD window was observed between 110 and 125°C , with saturated growth shown on TaN still at 135°C . Precursor self-decomposition in a chemical vapor deposition mode led to bimodal growth on Ta, resulting in the parallel formation of continuous films and isolated clusters. This effect was not observed on TaN up to ∼130°C and neither on Ru or SinormalO2 for any processing temperature. The degree of nitridation of the tantalum nitride underlayers considerably influenced the film growth. With excellent adhesion of the ALD films on all substrates studied, the results are a promising basis for Cu seed layer ALD applicable to electrochemical Cu metallization in interconnects of ultralarge-scale integrated circuits.

Consecutive synthesis methodologies for the preparation of a series of trimethylsilyl and tert‐butyl‐substituted ruthenocenes of the type Ru(η5‐C5H3R1R2)(η5‐C5H3R3R4) (2, R1 = SiMe3, R2 = R3 = R4 = H; 3, R1 = R3 = SiMe3, R2 = R4 = H; 4, R1 = R2 = R3 = SiMe3, R4 = H; 5, R1 = R2 = R3 = R4 = SiMe3; 6, R1 = R3 = tBu, R2 = R4 = H; 7, R1 = R3 = tBu, R2 = SiMe3, R4 = H; 8, R1 = R3 = tBu, R2 = R4 = SiMe3) and Ru(η5‐2,3‐Me2C5H5)(η5‐C5H4R) (10, R = tBu; 12, R = SiMe3) are discussed and their use as a MOCVD precursor for the deposition of ruthenium is reported. The molecular structures of 3, 5–8, 10, and 12 in the solid state are reported. The half‐open ruthenocenes 10 and 12, which are liquids at ambient temperature, exhibit significantly shorter Ru–centroid (η5‐2,3‐Me2C5H5) bond lengths in contrast to ruthenocenes 3 and 5–8. The thermal behavior of all ruthenocenes was studied by thermogravimetric analysis showing that they evaporate without decomposition at atmospheric pressure. In addition, vapor pressure measurements were carried out to obtain profound information about the volatility of the synthesized sandwich compounds. The highest vapor pressures were found for 10 and 12. It was observed that the higher the number of SiMe3 groups, the higher the deposition temperature. All compounds were applied as precursors in MOCVD. The depositions on Si/SiO2 targets were carried out in a vertical cold‐wall CVD reactor between 633 and 688 K with a flow rate of 50 mL min–1 using nitrogen as the carrier gas and oxygen as the coreactant (50 mL min–1). With the tBu‐functionalized ruthenocenes 6 and 10 ruthenium thin films were obtained, while mixed ruthenium/SiO2 layers were formed with 2, 7, 8, and 12. The appropriate layers possess thicknesses between 75–135 nm and are conformal and dense as proven by SEM, EDX spectroscopy, and XPS studies.

The atomic layer deposition (ALD) of copper oxide films from [(nBu3P)2Cu(acac)] and wet oxygen on SiO2 and TaN has been studied in detail by spectroscopic ellipsometry and atomic force microscopy. The results suggest island growth on SiO2, along with a strong variation of the optical properties of the films in the early stages of the growth and signs of quantum confinement, typical for nanocrystals. In addition, differences both in growth behavior and film properties appear on dry and wet thermal SiO2. Electron diffraction together with transmission electron microscopy shows that nanocrystalline Cu2O with crystallites < 5 nm is formed, while upon prolonged electron irradiation the films decompose and metallic copper crystallites of ~ 10 nm precipitate. On TaN, the films grow in a linear, layer-by-layer manner, reproducing the initial substrate roughness. Saturated growth obtained at 120{degree sign}C on TaN as well as dry and wet SiO2 indicates well-established ALD growth regimes.

We set out to study the use of a series of ruthenocenes as possible and promising sources for ruthenium and/or ruthenium oxide film formation.The thermal stability of a series of ruthenocenes, including (η5-C5H4R)(η5-C5H4R´)Ru (1), R = R´ = H (3), R = H, R´ = CH2NMe2 (5), R = H, R´= C(O)Me (6), R = R´ = C(O)Me (7), R = H, R´ = C(O)(CH2)3CO2H (8), R = H, R´ = C(O)(CH2)2CO2H (9), R = H, R´ = C(O)(CH2)3CO2Me (10), R = H, R´= C(O)(CH2)2CO2Me (11), R = R´ = SiMe3), (η5-C4H3O-2,4-Me2)2Ru (2), and (η5-C5H5-2,4-Me2)2Ru (4) was studied by thermogravimetry. From these studies, it could be concluded that 1–4, 6 and 9–11 are the most thermally stable molecules. The sublimation pressure of these sandwich compounds was measured using a Knudsen cell. Among these, the compound 11 shows the highest vapor pressure.

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