Copper oxide ALD from a Cu(I) beta-diketonate: Growth studies and application as seed layers for electrochemical copper deposition

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.