Poisson’s ratio and residual strain of freestanding ultra-thin films
Name
Wrinkling_Cuddalorepatta_nocolors.pdf
Description
Accepted version
Size
10.58 MB
Format
Adobe PDF
Checksum (MD5)
0b0629415367ebc9dc38113262b3082c
Author(s)
Cuddalorepatta, Gayatri K.
Van Rees, Willem Marinus
Han, Li
Pantuso, Daniel
Mahadevan, L.
Vlassak, Joost J.
Date Issued
April 2020
Journal
Journal of the Mechanics and Physics of Solids
Publisher
Elsevier BV
Citation
Cuddalorepatta, Gayatri K. et al. "Poisson’s ratio and residual strain of freestanding ultra-thin films." Journal of the Mechanics and Physics of Solids 137 (April 2020): 103821 © 2019 Elsevier Ltd
Version
Author's final manuscript
Abstract
The Poisson's ratio and residual strain of ultra-thin films (<100 nm) are characterized using the phenomenon of transverse wrinkling in stretched bridges. The test methodology utilizes residual stress driven structures and easy to replicate clean-room fabrication and metrology techniques that can be seamlessly incorporated into a thin-film production assembly line. Freestanding rectangular ultra-thin film bridges are fabricated using dimensions that generate repeatable transverse wrinkling patterns. Numerical modeling based on the non-linear Koiter plate and shell energy formulation is conducted to correlate the Poisson's ratio and residual strain to the measured wrinkling deformation. Poisson's ratio affects the peak amplitudes without significantly changing the wavelength of the wrinkles. By contrast, the strain affects both the wavelength and amplitude. The proof of concept is demonstrated using 65 nm thick copper films. A Poisson's ratio of 0.34 ± 0.05 and a tensile residual strain of [Formula presented] are measured. The measured residual strain is in good agreement with the residual strain of [Formula presented] measured using alternate residual stress-driven test structures of the same films.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
Terms of Use
Creative Commons Attribution-NonCommercial-NoDerivs License
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1016/j.jmps.2019.103821
