The electromigration effect revisited: Non-uniform local tensile stress-driven diffusion

Shih Kang Lin, Yu Chen Liu, Shang Jui Chiu, Yen Ting Liu, Hsin Yi Lee

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

The electromigration (EM) effect involves atomic diffusion of metals under current stressing. Recent theories of EM are based on the unbalanced electrostatic and electron-wind forces exerted on metal ions. However, none of these models have coupled the EM effect and lattice stability. Here, we performed in situ current-stressing experiments for pure Cu strips using synchrotron X-ray diffractometry and scanning electron microscopy and ab initio calculations based on density functional theory. An intrinsic and non-uniform lattice expansion - larger at the cathode and smaller at the anode, is identified induced by the flow of electrons. If this electron flow-induced strain is small, it causes an elastic deformation; while if it is larger than the yield point, diffusion as local stress relaxation will cause the formation of hillocks and voids as well as EM-induced failure. The fundamental driving force for the electromigration effect is elucidated and validated with experiments.

Original languageEnglish
Article number3082
JournalScientific reports
Volume7
Issue number1
DOIs
Publication statusPublished - 2017 Dec 1

All Science Journal Classification (ASJC) codes

  • General

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