Electrochemically Induced Deposition (ECiD): A Versatile Method that Greatly Extends the Portfolio of Surface Coatings and Materials Fabricated by Electrochemical Deposition

Abstract

Electrochemical deposition captures a wide variety of materials, ranging from the electroplating of metals, alloys, and semiconductors to the electro-polymerization of polymers. Deposition can be done from both aqueous and non-aqueous solutions, but also from ionic liquids and molten salts. In more general terms, electrochemical deposition comprises all processes of (electro)chemical conversion of species initially dissolved in an electrolyte solution into a poorly soluble or insoluble compound, leading to their deposition onto an electrode surface. In the case of direct electrodeposition, this conversion is the direct result of an electrochemical change (i.e., by electroreduction or electro-oxidation of the dissolved species). The best-known examples are cathodic electrodeposition of metals from metal ion solutions such as copper plating from an aqueous solution of CuSO4 and sulfuric acid, where the Cu2+ ions are reduced by direct electron transfer of two electrons (e2 reaction) at the copper metal cathode: (equation presented) The obtained metal deposits are dense and smooth and are, for example, used as surface decoration coatings on shaped surfaces or to fill small cavities, such as for copper interconnects in computer chips.1,2 As the metal product is a perfect electronic conductor, there is in principle no limit on its thickness.