Corrosion Protection of Copper Using Al₂O₃, TiO₂, ZnO, HfO₂, and ZrO₂ Atomic Layer Deposition

Atomic layer deposition (ALD) is a viable means to add corrosion protection to copper metal. Ultrathin films of Al₂O₃, TiO₂, ZnO, HfO₂, and ZrO₂ were deposited on copper metal using ALD, and their corrosion protection properties were measured using electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV). Analysis of ∼50 nm thick films of each metal oxide demonstrated low electrochemical porosity and provided enhanced corrosion protection from aqueous NaCl solution. The surface pretreatment and roughness was found to affect the extent of the corrosion protection. Films of Al₂O₃ or HfO₂ provided the highest level of initial corrosion protection, but films of HfO₂ exhibited the best coating quality after extended exposure. This is the first reported instance of using ultrathin films of HfO₂ or ZrO₂ produced with ALD for corrosion protection, and both are promising materials for corrosion protection.