Pure iridium thin films are prepared using iridium(ethylcyclopentadienyl)(1,5-cyclooctadiene) [Ir(EtCp)(1,5-COD)] with toluene solvent by liquid delivery metal-organic (MO)CVD. The deposition of Ir thin films is carried out on various substrates at temperatures in the range 300 -500°C via the oxygen-assisted pyrolysis of the precursor. The reaction kinetics, film composition, film morphology, mechanical and electrical properties of deposited Ir films are investigated. Annealing in an oxidizing atmosphere at temperatures above 700°C results in an increased oxidation of the films, as proven by X-ray diffraction (XRD) analyses. Obtained films show a low resistivity of 7 lX·cm and preferred crystalline orientation (111), suitable for application in storage capacitor electrodes.

No abstract

Thin iridium films are required as electrode material for ferroelectric capacitors. SBT (SrBi2Ta2O9) or PZT (Pb(ZrXTi1-X) O3) are often used as ferroelectric material in such capacitors. The PZT based non-volatile ferroelectric random access memories show better fatigue characteristics if platinum is replaced by iridium as electrode material. The iridium films were deposited on different substrates at room temperature by electron gun evaporation and at temperatures of 300 - 500 {degree sign}C by liquid-delivery MOCVD. The precursor Ir(EtCp) (1,5COD) [iridium(ethylcyclopentadienyl)(1,5-cyclooctadiene)] was diluted in toluene (0.1 M concentration) for the deposition experiments. The iridium films were deposited onto TiO2/SiO2/Si-, SiO2/Si-, and Si-substrates to compare the iridium film properties on different substrates. Annealing in an oxidizing ambient at temperatures above 700 {degree sign}C resulted in an increased oxidation of the CVD - films as proved by XRD analyses. Low resistivities of 7 - 70 µWcm were obtained for the as-deposited iridium films.

Thin iridium films are required as electrode material for ferroelectric capacitors. SBT or PZT are often used as ferroelectric material in such capacitors. The PZT based non-volatile ferroelectric random access memories show better fatigue characteristics if platinum is replaced by iridium as electrode material. Metalorganic chemical vapor deposition (MOCVD) was used for the deposition because of the superior step coverage on three-dimensional structures compared to the conventional physical vapor deposition processes of metal layers. Particularly, in memory fabrication, good step coverage is essential. The iridium films were deposited on different substrates at temperatures of 300 – 500 °C by liquid-delivery MOCVD. The precursor Ir(EtCp)(1,5COD) [iridium(ethylcyclopentadienyl)(1,5-cyclooctadiene)] was diluted in toluene (0.1 M concentration) for the deposition experiments. The iridium films were deposited onto TiO2/SiO2/Si-, SiO2/Si-, and Si-substrates to compare the iridium film properties on different substrates. The growth conditions like oxygen flow, growth temperature, and reactor pressure were varied. The growth rates were in a range between 0.05 and 4.6 nm per minute. We found that the growth rates were highly influenced by the oxygen flow and the substrate material. Oxygen assisted the decomposition of the precursor, and carbon and hydrogen of the organic source were oxidized, which suppressed its incorporation into the iridium layer. Annealing in an oxidizing ambient at temperatures above 700 °C resulted in an increased oxidation of the films as proved by XRD analyses. The resistivity of the films was determined by the Van-der-Pauw method. Low resistivities of 7 – 70 µΩcm were obtained for the as-deposited iridium films.

No abstract