Adsorption behavior and the effect of organic additives on tin electrodeposition process were studied utilizing combined electrochemical and surface enhanced Raman spectroscopy (SERS) techniques. The adsorption behavior of polyethylene glycols with and without hydrophobic head group was correlated with the morphology of the deposit. SERS experiments suggest that the head group part of the molecule remains adsorbed at all potentials studied. The potential dependence of the adsorption is primarily due to the hydrophilic tail in the Triton X100 family of compounds. The head groups of Triton X compounds are not required for adsorption but significantly enhance it. Triton X also enhances phenolphthalein adsorption on gold or silver surfaces and weakly interacts with it through some kind of supramolecular interactions. The coadsorption of Triton X100 and phenolphthalein significantly changes the grain size and the deposit structure of the electroplated tin as compared to Triton X alone. (C) 2003 The Electrochemical Society.