Growth and nanostructure of conformal ruthenium films by liquid-source metalorganic chemical vapor deposition

A commercially available metalorganic compound, namely Bis (2,2,6,6-tetramethyl-3, 5-heptanedionato)(1,5-cyclooctadiene)Ruthenium, or Ru(THD)(2)COD was evaluated for growth, nanostructure, and conformality of ruthenium films using a manufacturable, liquid-source metalorganic chemical vapor deposition technique. The deposition of Ru films (60-200 nm) was carried out on various substrates at a temperature (T-sub) of 250-320 degreesC via the oxygen-assisted pyrolysis of Ru(THD)(2)COD. In the kinetically controlled regime, the activation energy for the deposition of Ru on amorphous-HfO2/SiO2/Si was 136 kJ/mol. However, at T-sub>290 degreesC, the nearly temperature-independent growth rate was indicative of the mass-transport controlled regime. The as-deposited Ru films exhibited dense and polycrystalline grain structure, with a moderate preference for the (001) orientation. X-ray photoelectron spectroscopy revealed the presence of RuO2 in metallic Ru films deposited at a T-sub as low as 260 degreesC. In addition, high-resolution transmission electron microscopy showed amorphous grain boundaries in Ru films and a disorder interface layer between Ru and HfO2 surface. The Ru films, however, were electrically conductive (27 muOmega cm). In addition, Ru films deposited on patterned TiN/Si substrates in the kinetically controlled regime at 250 degreesC exhibited nearly 100% step coverage. (C) 2003 American Institute of Physics.