Pulsed-Chemical Vapor Deposition of Ruthenium and Ruthenium Dioxide Thin Films using RuO4 Precursor for the DRAM Capacitor Electrode

The deposition of Ru and RuO2 thin films, either by metal-organic chemical vapor deposition (MOCVD) or atomic-layer-deposition (ALD), has been studied extensively using a variety of metal-organic (MO) precursors for applications in capacitors for dynamic random access memory (DRAM) using high-dielectric TiO2 or SrTiO3 films. Because most ALD processes for Ru and RuO2 films proceed using a MO precursor, films deposited using these methods generally contain carbon and other impurities. This results in insufficient thermal stability and adverse interference with the electrical performance of the dielectric films grown on top. In this study, inorganic RuO4 was used as the precursor for the Ru and RuO2 electrodes fabrication. The largely improved electrical properties of TiO2 dielectric film on these electrodes are reported.