Small-scale plasticity in thin Cu and Al films

Gerhard Dehm, T. John Balk, Hervais Edongué, Eduard Arzt

Research output: Contribution to journalConference articlepeer-review

96 Scopus citations

Abstract

Flow stresses in thin metal films significantly exceed the flow stresses of their bulk counterparts. In order to identify the underlying deformation mechanisms and correlate them with microstructure, we analysed epitaxial and polycrystalline Cu and Al thin films. The films (100-2000 nm thickness) were magnetron sputtered on (0001) α-Al2O3 single crystals or on nitrided and oxidised (001) Si substrates. For epitaxial films, the flow stress measurements, which were obtained from substrate-curvature tests, agree with predictions from a dislocation-based model, whereas for polycrystalline films the stresses measured for film thicknesses down to 400 nm are much higher than predicted. However, thinner films reveal a plateau in room temperature flow stress. This behavior, as well as the stress-temperature evolution of the various films will be discussed in terms of existing theories for plasticity in thin metal films, and under consideration of recent in situ transmission electron microscopy studies.

Original languageEnglish
Pages (from-to)412-424
Number of pages13
JournalMicroelectronic Engineering
Volume70
Issue number2-4
DOIs
StatePublished - Nov 2003
EventMaterials for Advanced Metallization 2003 - La Londe Les Maures, France
Duration: Mar 9 2003Mar 12 2003

Bibliographical note

Funding Information:
GD thanks Dr. M. Legros and Dr. B. Inkson for stimulating discussions and fruitful collaborations. HE acknowledges financial support by the DFG via the Graduiertenkolleg innere Grenzflächen. Part of this work is supported by the DFG project DE 796/5-3. The authors thank Professor H. Gao for many helpful discussions. Dr. T. Wagner and his team from the ‘ZWE Dünnschicht’ are acknowledged for assistance with thin film deposition and Professor M. Rühle for use of the TEM facilities.

Keywords

  • Diffusional creep
  • Dislocation
  • Hillock
  • Passivation
  • Size effect
  • Thin film plasticity

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Electrical and Electronic Engineering

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