MICROSTRUCTURE EVOLUTION OF NEWLY DEVELOPED ELECTROLESS RUTHENIUM DEPOSITION ON SILICON OBSERVED BY SCANNING-TRANSMISSION ELECTRON-MICROSCOPE

Autocatalytic Ruthenium thin films have been successfully deposited on silicon. The deposition reactions were proven to be electroless by the measurement of the electrochemical rest potentials of anodic and cathodic partial reactions and mixed potentials. A new method for direct observation of microstructure and formation at the initial stage of deposition has also been developed. The progressive formation and microstructure of ruthenium thin films during various growth stages have been investigated by scanning transmission electron microscopy. Deposition takes place immediately after the n-type silicon is immersed in the electroless plating solution. The film was identified to be amorphous by the selected area electron diffraction analysis. Cross-sectional transmission electron microscopy method was utilized to explore the uniformity and morphology of the film as well as the Ru/Si interface. Accordingly, the deposition rate was also measured with a high precision nanometer. The microstructure evolution and significance in applications are also discussed.