Dendritic Growth and Morphology Selection in Copper Electrodeposition from Acidic Sulfate Solutions Containing Chlorides

• Published in: Journal of physical chemistry. C Vol. 113; no. 23; pp. 10097 - 10102
• Main Authors: Shao, Wenbo, Zangari, Giovanni
• Format: Journal Article
• Language: English
• Published: American Chemical Society 11.06.2009
• Subjects: C: Surfaces, Interfaces, Catalysis
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp8095456

We investigate the morphology of Cu films electrodeposited onto silicon from an acidic sulfate electrolyte with the addition of a variable concentration of chloride anions. Addition of chloride increases grain size and the degree of grain faceting while decreasing the density of growth nuclei. Well-developed monocrystalline dendrites are formed in acidic sulfate solutions with high concentration of chloride. Dendrites form under growth conditions that either approach diffusion limitation, or occur within a potential range where different crystallographic faces exhibit a different potential dependence for chloride desorption. The presence of dendrites however is mainly related to the fact that the reduction route Cu2+ → CuCl → Cu becomes the rate-determining process in solutions with high chloride concentration; the rate of this reaction is largest at {110} planes, where the concentration of chloride anions is the highest, generating dendrites with branches along the {110} directions.