Thermal stability and deposition behaviors of Ru thin films prepared by using metalorganic chemical vapor deposition

Ru thin films were deposited on Ta2O5 and TiN substrates by using metal-organic chemical vapor deposition (MOCVD) with cyclopentadienyl-propylcyclopentadienlylruthenium (II) [RuCp(i-PrCp)]. The thermal stability of the Ru films, which were located between the diffusion barriers and the high-dielectric films used as bottom electrodes, was investigated. We deposited Ti-doped Ru films to improve the thermal stability of the Ru films. We found that the increase in the surface roughness of Ti-doped Ru films with low Ti addition was suppressed during annealing. It seems that the TiOx phase formed at the grain boundary of the Ru grain inhibited growth of the Ru grain. We also improved the interface property of Ru/TiN through H2 annealing and found that the Ru-RuO2 film deposited on the TiN surface had more RuO2 phases than the Ru-RuO2 films deposited on Ta2O5 due to the different nucleation barriers for the deposition of Ru thin films.