Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8129904 | Ultrasonics | 2018 | 22 Pages |
Abstract
We have used the ultrafast pump-probe technique known as picosecond ultrasonics to generate and detect surface acoustic waves on a structure consisting of nanoscale Al lines on SiO2 on Si. We report results from ten samples with varying pitch (1000-140â¯nm) and SiO2 film thickness (112â¯nm or 60â¯nm), and compare our results to an isotropic elastic calculation and a coarse-grained molecular dynamics simulation. In all cases we are able to detect and identify a Rayleigh-like surface acoustic wave with wavelength equal to the pitch of the lines and frequency in the range of 5-24â¯GHz. In some samples, we are able to detect additional, higher frequency surface acoustic waves or independent modes of the Al lines with frequencies close to 50â¯GHz. We also describe the effects of probe beam polarization on the measurement's sensitivity to the different surface modes.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Acoustics and Ultrasonics
Authors
Michael Colletta, Wanjiru Gachuhi, Samuel A. Gartenstein, Molly M. James, Erik A. Szwed, Brian C. Daly, Weili Cui, George A. Antonelli,