电迁移诱导W纳米晶表面原子尺度结构演变

电迁移诱导W纳米晶表面原子尺度结构演变

曹海镟^#，赵培丽^#，贾双凤，郑  赫^*，王建波^*

（1. 武汉大学物理科学与技术学院，电子显微镜中心，人工微结构教育部重点实验室和高等研究院，湖北  武汉 430072；2. 武汉大学科研公共服务条件平台，湖北 武汉 430072）

摘    要   体心立方（BCC）金属W作为微型化器件中重要的互连材料，其电迁移行为对小尺寸集成电路的稳定性至关重要。本文利用原位TEM技术，在原子尺度下研究了电迁移诱导BCC金属W表面结构动态演变过程。结果表明，自由表面是主要电迁移路径；而{110}面和<111>方向分别是优选的迁移面迁移方向；电迁移过程中W表面形成特定的原子台阶或锯齿状结构。对于非低能晶面{002}，在电流作用下仍能发生定向迁移，形成新的台阶结构。研究结果揭示了电迁移过程中表面结构的演化规律，为优化BCC金属材料的微观结构设计、提高其在高电流密度环境下的结构性能稳定性提供借鉴。

关键词    电迁移；钨；低能面；表面原子；原位透射电子显微镜

中图分类号：TG115. 21⁺ 5. 3；O766⁺. 1；O799；O722⁺. 4；O739；TN16    文献标识码：A         doi：10.3969/j.issn.1000-6281.2024.05.002

Atomic scale surface structure evolution of W nanocrystals induced by electromigration

CAO Haixuan^1#, ZHAO Peili^1#, JIA Shuangfeng¹, ZHENG He^1*, WANG Jianbo^1,2*

（1. School of Physics and Technology, Center for Electron Microscopy, MOE Key Laboratory of Artificial Micro- and Nano-structures, and Institute for Advanced Studies, Wuhan University, Wuhan Hubei 430072；

2. Core Facility of Wuhan University, Wuhan Hubei 430072, China）

Abstract    Body centered cube (BCC) metal tungsten (W) is a critical interconnect material in miniaturized devices. Its electromigration behavior at the nanoscale significantly affects the stability of integrated circuits. Using in-situ TEM technology, we investigated the dynamic surface structure evolution in W induced by electromigration. The results revealed that the free surface was the primary pathway for electromigration, with a preferential migration direction along the <111> direction within the {110} plane, leading to the formation of specific atomic terraces or zigzag structures. Even on higher-energy crystal planes such as {002}, directional migration persists under the influence of electric current, leading to the development of new terrace structures. These insights into the evolution patterns of surface structures during electromigration provide valuable guidance for optimizing the microstructural design of BCC metallic materials and enhancing their structural performance stability in high-current-density environments.

Keywords electromigration;tungsten;low energy surface;surface atoms;in situ transmission electron microscopy

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