MOCVD of titanium dioxide on the basis of new precursors

Thin films with a considerably higher dielectric constant than silicon dioxide, for example titanium dioxide or titanium containing barium strontium titanate, can be used for dielectrics in ultralarge scale integration (ULSI) devices. TiO2 shows, besides its high dielectric constant, a sufficiently low leakage current and high breakdown field strength. MOCVD is the most promising method for depositing those dielectrics because of its obvious advantages like homogeneity of films, good step coverage and ultra-thin film deposition. In this work, three new precursor chemicals have been developed and tested in a low pressure horizontal cold wall-type furnace. For the synthesis of the novel precursors, commercial titanium-iso-propylate is brought to an reaction with an alcoholic compound at 150°C and distilled under vacuum. The motivation for the development of new Ti precursors lies in an improvement of the handling and deposition characteristics as for example the hydrolytic stability. For the three precursors the deposition parameters temperature, pressure, gas flow and activation energy is presented. The electrical properties dielectric constant and leakage current were compared to commercially available titanium-iso-propylate.