Pulsed Potentiostatic Deposition of Gold from Solutions of the Au(I) Sulfite Complex

Abstract

The kinetics of Au deposition from Au(I) sulfite solutions in the pH range 8.5-13 has been studied using cyclic voltammetry and single potential step methods. At potentials more positive than −0.8V vs. NHE, the potential step data can be explained by a C.E. mechanism, probably dissociation of the gold complex followed by charge transfer. At more cathodic potentials the mechanism may involve direct electron transfer to the complexed gold ion. The effect of pulsed potentiostatic deposition on the properties of Au films deposited from sulfite solutions was investigated. Although variation of the frequency of the potential pulse was shown to affect the distribution of Au deposited through a photoresist pattern, the stress, grain size, purity, and resistivity of gold deposited pulsed potentiostatically showed no clear dependence on frequency. This can be explained in terms of irreversibility of the Au/Au(I) couple in sulfite solution. © 1977, The Electrochemical Society, Inc. All rights reserved.