An In Situ Ellipsometric Study of Cl- -Induced Adsorption of PEG on Ru and on Underpotential Deposited Cu on Ru

Published

January 1, 2006

Author(s)

Marlon L. Walker, Lee J. Richter, Daniel Josell, Thomas P. Moffat

Abstract

The adsorption of PEG-Cl on a.) air-oxidized Ru, b.) reduced or activated Ru and c.) underpotential deposited (upd) Cu on activated Ru was examined in-situ using spectroscopic ellipsometry. In the absence of Cl- ion, PEG adsorption was minimal at all potentials and on all surfaces characterized in this study. On activated Ru, the addition of Cl- ion resulted in PEG coadsorption. At potentials relevant to Cu upd, a three-component PEG-Cl--Cu layer forms independent of the order of additive addition to the electrolyte. The PEG-Cl--Cu upd overlayer provides inhibition of subsequent Cu overpotential deposition. At potentials positive of Cu upd, a monolayer oxide film forms that inhibits PEG adsorption even in the presence of Cl-. Ru oxidation exerts a strong effect on the adsorption of additives that are directly relevant to the nucleation and growth of electrodeposited Cu.

Citation

Journal of the Electrochemical Society

Volume

153

Issue

No. 4

Pub Type

Journals

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Keywords

coadsorption under potential deposition, Cu electrodeposition, Cu upd, PEG-C1, Ru Barrier material, spectroscopic ellipsomety, superfilling

Citation

Walker, M. , Richter, L. , Josell, D. and Moffat, T. (2006), An In Situ Ellipsometric Study of Cl^- -Induced Adsorption of PEG on Ru and on Underpotential Deposited Cu on Ru, Journal of the Electrochemical Society, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=831389 (Accessed October 11, 2025)