Investigating the Surface and Microstructure of Electrodeposited Cu Films

Abstract

Both morphology and microstructure play a crucial role in determining the properties of an electrodeposited polycrystalline thin film and its performance in different applications. We have investigated the morphology of Cu films electrodeposited from a chloride-containing acid sulfate electrolyte by applying a combination of conventional ex-situ AFM and in-situ High-Speed AFM (HS-AFM). For the HS-AFM studies, a film was grown on a microelectrode, 30µm in diameter and imaged in-situ in real time. The high-speed flexure stage of HS-AFM enables it to scan the surface of the film up to 1000 times faster than the conventional AFM [1], which provides many details about how the film growth is proceeding and how the structure coarsens with deposition time [2]. Here, we compare data from films prepared by continuous and pulse deposition. We also present microstructural data obtained with the help of focussed ion beam milling.[1] Oliver D Payton, Loren Picco, and Thomas Bligh Scott. High-speed atomic force microscopy for materials science. International Materials Reviews, 61(8):473-494, 2016.[2] Aswathi Koorikkat, Oliver Payton, Loren Picco, and Walther Schwarzacher. Imaging the surface of a polycrystalline electrodeposited cu film in real time using in situ high-speed AFM. Journal of the Electrochemical Society, 167(16):162510, 2020.