Atomic layer deposition of TiO2 films on Ru buffered TiN electrode for capacitor applications

This study examined the effect of a Ru buffer layer growth on a TiN electrode on the structural and electrical properties of a TiO2 dielectric film grown by atomic layer deposition. The growth of a TiO2 film directly on TiN resulted in the formation of a mixture of anatase and rutile TiO2 with a dielectric constant of only 42. However, interposing a thin Ru layer altered the crystal structure of TiO2 from a mixed phase to almost pure rutile, which was accompanied by an abrupt increase in the dielectric constant to ∼130. This is a much better result compared with the TiO2 film deposited on a bulk Ru film, which showed a dielectric constant of ∼80. This improvement was attributed to a change in the preferred growth direction of a TiO2 film on the Ru/TiN layer compared with that on a thicker Ru film.