English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
  Time-dependent plasticity in silicon microbeams mediated by dislocation nucleation

Elhebeary, M., Harzer, T. P., Dehm, G., & Saif, M. T. A. (2020). Time-dependent plasticity in silicon microbeams mediated by dislocation nucleation. Proceedings of the National Academy of Sciences of the United States of America, 117(29), 16864-16871. doi:10.1073/pnas.2002681117.

Item is

Basic

show hide
Genre: Journal Article

Files

show Files

Locators

show

Creators

show
hide
 Creators:
Elhebeary, Mohamed1, Author
Harzer, Tristan Philipp2, Author              
Dehm, Gerhard3, Author              
Saif, M. Taher A.4, Author              
Affiliations:
1Mechanical Science and Engineering Department, University of Illinois at Urbana–Champaign, Urbana, IL 61801, ou_persistent22              
2Advanced Transmission Electron Microscopy, Structure and Nano-/ Micromechanics of Materials, Max-Planck-Institut für Eisenforschung GmbH, Max Planck Society, ou_1863399              
3Structure and Nano-/ Micromechanics of Materials, Max-Planck-Institut für Eisenforschung GmbH, Max Planck Society, ou_1863398              
4Mechanical Science and Engineering Department, University of Illinois at Urbana-Champaign, 1206 W Green Street, Urbana, IL 61801, USA, ou_persistent22              

Content

show
hide
Free keywords: silicon, Article; atomic force microscopy; high temperature; physical parameters; priority journal; qualitative analysis; quantitative analysis; shear stress; temperature sensitivity; temperature stress; threshold stress; transmission electron microscopy
 Abstract: Understanding deformation mechanisms in silicon is critical for reliable design of miniaturized devices operating at high temperatures. Bulk silicon is brittle, but it becomes ductile at about 540 °C. It creeps (deforms plastically with time) at high temperatures (∼800 °C). However, the effect of small size on ductility and creep of silicon remains elusive. Here, we report that silicon at small scales may deform plastically with time at lower temperatures (400 °C) above a threshold stress. We achieve this stress by bending single-crystal silicon microbeams using an in situ thermomechanical testing stage. Small size, together with bending, localize high stress near the surface of the beam close to the anchor. This localization offers flaw tolerance, allowing ductility to win over fracture. Our combined scanning, transmission electron microscopy, and atomic force microscopy analysis reveals that as the threshold stress is approached, multiple dislocation nucleation sites appear simultaneously from the high-stressed surface of the beam with a uniform spacing of about 200 nm between them. Dislocations then emanate from these sites with time, lowering the stress while bending the beam plastically. This process continues until the effective shear stress drops and dislocation activities stop. A simple mechanistic model is presented to relate dislocation nucleation with plasticity in silicon. © 2020 National Academy of Sciences. All rights reserved.

Details

show
hide
Language(s): eng - English
 Dates: 2020-07-21
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: -
 Identifiers: DOI: 10.1073/pnas.2002681117
 Degree: -

Event

show

Legal Case

show

Project information

show

Source 1

show
hide
Title: Proceedings of the National Academy of Sciences of the United States of America
  Abbreviation : PNAS
  Abbreviation : Proc. Natl. Acad. Sci. U. S. A.
Source Genre: Journal
 Creator(s):
Affiliations:
Publ. Info: Washington, D.C. : National Academy of Sciences
Pages: - Volume / Issue: 117 (29) Sequence Number: - Start / End Page: 16864 - 16871 Identifier: ISSN: 0027-8424
CoNE: https://pure.mpg.de/cone/journals/resource/954925427230