The Effects of an Iodine Surface Layer on Ru Reactivity in Air and during Cu Electrodeposition

Abstract

X-ray photoelectron spectroscopy (XPS), low energy electron diffraction, and cyclic voltammetry have been used to study the adsorption of iodine on the Ru(0001), air, and water exposure to both clean and iodine covered Ru(0001) surfaces and the stability of the iodine adlayer during Cu overpotential electrodeposition. A normalRufalse(0001false)­false(3×3false)R30°­I structure was observed after I2 vapor exposure of the Ru(0001) surface at room temperature. The normalRufalse(0001false)­false(3×3false)R30°­I structure was found to be stable toward ambient air and water exposure. The I ad-layer passivates the Ru(0001) surface against significant hydroxide, chemisorbed oxygen, or oxide formation during exposure to air. Immersion of I-Ru(0001) results in greater hydroxide and chemisorbed oxygen formation than air exposure. A saturation coverage of I on a Ru(poly) electrode similarly passivated the Ru surface against oxidation upon exposure to water vapor over an electrochemical cell in an ultrahigh vacuum electrochemistry transfer system. Studies with combined electrochemical and XPS techniques show that iodine surface adlayer remained on top of the surface after cycles of overpotential electrodeposition/dissolution of copper on Ru(0001). These results indicate the potential bifunctionality of the iodine layer to both passivate the Ru surface in the microelectronic processing and to act as a surfactant for copper electrodeposition. © 2004 The Electrochemical Society. All rights reserved.

Copper underpotential deposition on Ru quasi-single-crystal films

“…The charge density for the oxidation/dissolution of the first Cu-layer was found to be 600 ± 40 lC cm À2 . The group of Kelber et al [45][46][47] studied the growth kinetics and nucleation behaviour of Cu deposited on Ru(0 0 0 1) and polycrystalline Ru with X-ray photoelectron spectroscopy (XPS), and the influence of chloride and iodide on Cu deposition. Chloride was found to induce the formation of a Cu(I) species on top of Ru.…”

Cu electrodeposition on Ru(0001): Perchlorate dissociation and its effects on Cu deposition

“…Spectral components with full width at half maximum (FWHM) value of 1.7 eV were used to fit experimental O(1s) spectra. The assignment of this FWHM is based on a recent study in our laboratory, which involved a systematic examination of oxide film growth on Ru(0001) and Ru(poly) [20]. The binding energy and FWHM of the spectral components remained fixed during the fitting procedure.…”

Electrochemical atomic layer deposition of copper nanofilms on ruthenium

“…Kelber et al reported that adsorbing I atoms from I 2 at 300 K passivated a ruthenium surface against oxidation. In addition, during overpotential Cu electrodeposition (OPD), the I atoms floated on top of the depositing Cu, thus maintaining the protection as the deposit grew [13]. The Stickney group has also studied the adsorption of Cl on Cu single crystal surfaces, where it was also shown to protect the surface, while forming a well ordered atomic layer [14][15][16].…”