Surface pretreatment of the underlying film to enhance Ru nucleation is essential in molecular organic chemical vapor deposition (MOCVD) of Ru. In the present work, effects of argon plasma, hydrogen plasma, and palladium sputtering treatments of the Ta-Si-N film surface on Ru nucleation in Ru MOCVD were investigated using scanning electron microscopy (SEM) and Auger electron emission spectrometry (AES) analyses. It was found from the analysis results that palladium sputtering treatment is the most efficient, argon plasma treatment is the next, and hydrogen plasma treatment is the third in enhancing Ru nucleation. Also, the mechanism through which Ru nucleation is enhanced by these pretreatments and why the nucleation enhancing efficiencies of these three pretreatments are different are discussed. (C) 2004 Published by Elsevier B.V.