Electrodeposition of Cu from Acidic Sulfate Solutions in the Presence of Bis-(3-sulfopropyl)-disulfide (SPS) and Chloride Ions

This paper reports an in situ Raman study of Cu electrodeposition from an acidic sulfate solution in the presence of bis-(3-sulfopropyl)-disulfide Na salt (SPS). In the absence of chloride, in situ surface-enhanced Raman spectra scarcely show few labile features in a narrow range of cathodic potential. When ions are added to the deposition bath, several features are clearly visible in the spectra, showing that SPS is adsorbed on the copper surface in a wide potential window during Cu electroplating.