Electric field-assisted dissolution of bimetal-dielectric multilayer systems

Abstract

The electric field-assisted dissolution (EFAD) of Ag and Au metal island films (MIFs) in multilayer structures is investigated. The samples consist of Au and Ag MIFs separated by SiO2 layers deposited on soda-lime glass substrates. The samples were subjected to two types of process: a) thermal annealing at 200°C, and b) application of 500 V dc voltage at 200°C. Spectroscopic ellipsometry and secondary ion mass spectrometry were used to track sample changes. It is shown that thermal annealing induces ion exchange between Ag and Na ions from the glass, leading to partial dissolution of Ag MIFs and Ag being incorporated in the glass and Au MIFs. EFAD process leads to the partial or complete dissolution of Ag films depending on the process duration, while Au dissolution turns out to be more difficult. The optical properties are consistent with the compositional changes and additionally suggest MIF morphology modifications. Numerical simulations of ion drift and diffusion reveal the importance of ion exchange during thermal annealing to enable an efficient MIF dissolution. Overall, the study helps to understand the EFAD of different metals in complex systems and provides insights for the application of this technique in systems containing several metals.