Low and high frequency pulse current plating of copper onto a rotating disk electrode

A comprehensive mathematical model for galvanostatic pulse plating has been developed and compared with the experimentally obtained electrode response during the deposition of copper from a sulfuric acid solution onto a rotating disk electrode. The model incorporates diffusional, convective, and migrational transport, electrode kinetics, and homogeneous reaction and capacitance effects due to the electrical double layer (dl) and the adsorption of an intermediate. The effect of the electrical dl at both low and high frequency pulse plating has been investigated. The model has been fit to the electrode potentials monitored during electrodeposition via a digital oscilloscope and been found to agree very well quantitatively with the experimental data over the frequency range from 50 Hz to 50 kHz, although the agreement decreases somewhat at the highest frequency. Analysis of the model shows that the effect of the pseudocapacitance due to the adsorption of a Cu+ intermediate plays a major role during pulse plating, while the effect of electrical dl capacitance is significant at low frequencies, but becomes very small at high frequencies. (C) 2002 The Electrochemical Society.