UV-Ozone Oxidation of ultra thin Ru layers*

Ruthenium and its oxides and nitrides are potential candidates for number of advanced applications in Silicon based semiconductor technology such as metal-based gate electrodes and diffusion barriers for copper interconnects. This is due to their good thermal stability, low resistivity, suitable work function and diffusion barrier properties. Physico-chemical and electrical properties of Ru oxides are intimately dependent on the oxide preparation method mainly due to the resulting microstructure, oxidation state and impurities/contaminants. 5 to 7 nm Ru films were deposited on Si and SiO2 substrates by DC magnetron sputtering in Ar atmosphere. The films were then exposed to UV/Ozone radiation and oxygen at room temperature for a duration ranging from 15 min to 60 min. In-situ X-ray photoelectron spectroscopy (XPS) is used to investigate Ru oxidation rate and the bonding environment. A comparison with Ru oxide prepared via reactive DC sputtering in an Ar/O2 mixture will be presented.