NSF/DMR-BSF: Diffusion along Metal-Ceramic Interfaces: a combined theoretical and experimental study

第一部分：非技术摘要本项目侧重于了解原子沿金属/陶瓷界面发生扩散的机制。沿金属/陶瓷界面的扩散在各种工业部门的许多工艺过程中起着关键作用，包括微电子(例如，互连界面)、工具(例如，Co-WC界面)和汽车(铂、钯-氧化铝催化剂界面)。这种界面扩散在很大程度上决定了金属互连线中的电迁移速度和薄膜中的应力松弛速度，以及金属催化剂的分散稳定性。由于缺乏可靠的数据和对基础科学的理解，阻碍了设计更好的组分和更稳定的催化剂。提供基础的、机械的科学和可靠的扩散数据是本项目的主要目标。第二部分：技术摘要本项目的主要目标是利用精确的实验测量和第一性原理计算技术，了解金属-陶瓷界面上金属扩散的微观、原子机制。这些研究将在同一组接口上并行执行。这一协同研究将建立金属沿金属/陶瓷界面扩散的机制，这些扩散建立了晶体固体中快速扩散路径的层次结构。这是一个关于金属原子在几种不同的金属-陶瓷界面上的自扩散和异扩散的并行和相关的计算和实验研究的重点程序。计算方法的可靠性将通过将模拟的原子结构和能量与同一组界面的实验确定的结构和能量进行比较来验证。这项工作确定了在广泛的多相体系应用中，哪些机制主导着传输动力学。这些实验将通过对陶瓷基板上的金属薄膜进行去湿来形成金属颗粒，然后用扩散剂覆盖。界面扩散将使用分析型HRTEM进行监测。这些模拟将使用第一性原理技术和分子动力学模拟相结合的方法解决点缺陷和界面能量学以及输运问题。

Part I: Non Technical AbstractThis 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 AbstractThe 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.