Anisotropy of electromigration-induced void and island drift

Area of Science:

• Surface science
• Materials science
• Computational physics

Background:

• Electromigration is a critical phenomenon in thin films, influencing device reliability.
• Understanding atomic-scale surface dynamics is essential for materials engineering.
• Previous models lacked the ability to capture complex void behavior under electromigration.

Purpose of the Study:

• To investigate the atomic-scale electromigration-induced drift of voids and islands on Ag(111) and Ag(001) surfaces.
• To analyze the size-dependent drift velocity and directional deviations of these surface features.
• To develop and utilize a novel self-learning kinetic Monte Carlo model for atomic-scale simulations.

Main Methods:

• Development of a novel self-learning kinetic Monte Carlo (SLKMC) model.
• Atomic-scale simulations of monolayer voids and islands on Ag(111) and Ag(001) surfaces.
• Systematic investigation of system parameters influencing drift behavior.

Main Results:

• A non-monotonic size dependence of drift velocity was observed for small voids.
• Drift direction aligned with the electromigration force only along high symmetry directions.
• Maximal angular deviation between drift direction and force occurred between high symmetry directions, dependent on system parameters.

Conclusions:

• The study provides atomic-scale insights into electromigration-induced void and island dynamics on silver surfaces.
• Simulation results align with experimental observations of void motion on Ag(111).
• The developed SLKMC model offers a powerful tool for studying complex surface phenomena.