Electrochemical deposition and stripping of copper, nickel and copper nickel alloy thin films at a polycrystalline gold surface: a combined voltammetry-coulometry-electrochemical quartz crystal microgravimetry study

Abstract

Cyclic voltammetry, anodic stripping voltammetry (ASV) and coulometry were used in conjunction with electrochemical quartz crystal microgravimetry (EQCM) and ex situ X-ray photoelectron spectroscopy (XPS) for a study of the electrodeposition and stripping of Cu, Ni and CuNi alloy thin films at a polycrystalline Au surface. A deaerated Watts bath was employed for the electrodeposition of Ni and CuNi thin films, the bath containing Cu 2+ ions (Ni:Cu = 200:1 mole ratio) in the latter case. These films showed the most satisfactory stripping in either 0.1 M HCl or 0.1 M H 2SO 4. Coulometry was used in conjunction with EQCM data for mapping the (potentiostatic) plating efficiency as a function of deposition potential in the Cu and Ni systems. For the CuNi alloy, similar data were acquired by additionally utilizing XPS compositional information and assuming current additivity in the (non-interactive) co deposition of Cu and Ni. Finally, the feasibility of employing the combined ASV-EQCM technique for analysis of CuNi/Ni bilayers is presented.