Role of ethylenediamine additive in Cu growth on a Co/SiO2/Si substrate via electrochemical atomic layer deposition of Pb and its surface limited redox replacement

Layer-by-layer growth of a Cu film on a Co-based barrier is increasingly demanded due to the continuous scaling down of electronic devices. However, studies of Cu films electrodeposited on a barrier are rare because the acidic Cu²⁺ electrolyte induces the galvanic corrosion on the Co-based barrier. This study showed that ethylenediamine addition to the Cu²⁺ electrolyte decreases the replacement rate of Cu²⁺ ions and prevents the corrosion of the Co-based substrate when the Cu film is deposited on the substrate by sequential underpotential deposition of Pb and surface-limited redox replacement of Cu. The properties of the Cu film were evaluated using X-ray diffraction, scanning electron microscopy and electrochemical analysis. The results showed that addition of 0.7 mM ethylenediamine can significantly improve the growth of Cu on a cobalt-based substrate by underpotential deposition of Pb and surface-limited redox replacement of Cu.