SYNTHESIS OF RUTHENIUM (IV) OXIDE ON TANTALUM BY ATOMIC LAYER DEPOSITION

Abstract

The results of synthesis of nanoscale films of ruthenium dioxide on tantalum are presented. The films were obtained by atomic layer deposition at the TFS 200 Beneq setup (production Finland). As precursors bis(ateltico-pentadienyl) ruthenium and oxygen were used. Nitrogen acted as an inert gas to purge the reaction chamber of precursor residues and reaction products. The synthesis was carried out in two stages: activation of the tantalum surface by hydroxyl groups and alternate supply of ruthenium and oxygen precursors to the reaction chamber under certain conditions. The main regularities of the process were revealed and the method of synthesis realization was proposed. It is shown that the synthesis result is influenced by the process parameters of the atomic layer deposition method. The main parameters affecting the process are the temperature in the reaction chamber and the precursor requiring heating, the time of the precursor intake and the time of nitrogen purging. Also, in the process of synthesis, such a parameter as "pause" is used-the temporary cessation of the supply of any reagents to the reaction chamber to increase the ratio of reacting molecules. The influence of each process parameter on the synthesis of thin films of ruthenium dioxide is substantiated and experimentally confirmed. It was concluded that the optimal deposition temperature of ruthenium dioxide is 220 °C. The optimum temperature of the heated precursor is 80 °C. The optimal time of the ruthenium precursor is 1 s, the time of the oxidizing agent is 10 s under the stated conditions. The optimal "pause" time is 3 s after the intake of bis (ethylcyclopentadienyl) ruthenium, and 5 s after the intake of oxygen. The presented method of synthesis of ruthenium dioxide will allow to obtain high-quality, uniform throughout the thickness of nanoscale films that can be used as an electrode in capacitors.