This project focuses on understanding the mechanisms by which atomic diffusion occurs along metal/ceramic interfaces. Diffusion along metal/ceramic interfaces plays a key role in a number of technological processes in a variety of industrial sectors, including microelectronics (e.g., interconnect interfaces), tooling (e.g., Co-WC interfaces), and automotive (Pt,Pd-alumina catalyst interfaces) sectors. This type of interface diffusion largely determines the rates of electromigration in metal interconnects and stress relaxation in thin films, and the dispersion stability of metal catalysts. The design of better components and more stable catalysts is impeded because of both the lack of reliable data and the understanding of the basic science. Providing both the fundamental, mechanistic science and reliable diffusion data are the main goals of this project.
Part II: Technical Abstract
The main objective of the proposed Project is to understand the microscopic, atomistic mechanisms of metal diffusion along the metal-ceramic interfaces employing precise experimental measurements and first-principle computational techniques. These studies will be performed in parallel on the same set of interfaces. This synergistic study will establish the mechanisms for metal diffusion along metal/ceramic interfaces, these diffusivities establish the hierarchy of fast diffusion paths in crystalline solids. This is a focused program of parallel and correlated computational and experimental studies of the self- and hetero-diffusion of metal atoms along several different metal-ceramic interfaces. The reliability of the computational methods will be verified by comparing simulated atomic structures and energies with the experimentally determined ones for the same set of interfaces. This work identifies which mechanisms dominate transport kinetics in a wide range of multiphase system applications. The experiments will be performed by dewetting a metal film on a ceramic substrate to form metal particles that are then coated with the diffusants. The interface diffusion will be monitored using analytical HRTEM. The simulations will address point defect and interface energetics and transport using first principles techniques coupled with molecular dynamics simulations.
