Ru nanodot synthesis using CO2 supercritical fluid deposition Original Research Article

CO2-based supercritical fluid deposition (SCFD) was utilized for the synthesis of ruthenium nanostructures on Si substrates and hafnium oxide (HfO2) films. Ru nanodots were formed by the reduction of a Ru precursor under a hydrogen environment. Ruthenium carbonyl was dissolved in supercritical CO2 in a pre-mix vessel, and this mixture was pumped into a reaction vessel which allowed it to undergo rapid expansion. The formation of Ru nanodots was studied as a function of key process parameters such as the weight of precursor used, the reaction temperature and the H2 reactant pressure. Utilizing the Ru nanodots on a HfO2 control oxide, a flash memory device containing nanodots was fabricated and its memory characteristics were demonstrated.