Hostname: page-component-cd9895bd7-8ctnn Total loading time: 0 Render date: 2024-12-28T22:14:50.235Z Has data issue: false hasContentIssue false
  • English
  • Français

Femtosecond Ultrasonics for the Characterization of Layered Micro- and Nano Structures

Published online by Cambridge University Press:  14 March 2011

Jacqueline Vollmann ,
Dieter Profunser  and
Jürg Dual
Jacqueline Vollmann
Affiliation:
Center of Mechanics ETH Zürich, (Swiss Federal Institute of Technology) CH 8092 Zürich, SWITZERLAND
Dieter Profunser
Affiliation:
Center of Mechanics ETH Zürich, (Swiss Federal Institute of Technology) CH 8092 Zürich, SWITZERLAND
Jürg Dual
Affiliation:
Center of Mechanics ETH Zürich, (Swiss Federal Institute of Technology) CH 8092 Zürich, SWITZERLAND
Get access

Abstract

The precise measurement of thicknesses, mechanical properties, and film-substrate bonding qualities of sub-micron metallic films, multi-layers, and microstructures in a nondestructive way is of growing importance for the semiconductor industry as well as for MEMS manufacturers.

Short laser pulses having durations of less than 100 fs are an ideal – not to say the only –way in order to provide sub-surface visualization in nanometer scale perpendicular to the film surface.

In this investigation, an enhanced pump-probe set up is presented. A dual frequency modulation technique is implemented in order to eliminate optical and electrical cross talk between the excitational pump pulse and the measuring probe pulse.

Up to the 5th acoustic echo in an aluminum film having a thickness of 50 nm on a sapphire substrate has been measured. From the time of flight and from the amplitude decay between the echoes the material properties of the film and of the substrate have been derived.

Further directions of the on going research project are presented.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 634: Symposium B – Structure and Mechanical Properties of Nanophase Materials-Theory & Computer Simulations vs. Experiment , 2000 , B3.3.1
Copyright
Copyright © Materials Research Society 2001

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Thomsen, C., Maris, H.J., Tauc, J., “Picosecond Acoustics as a Non-Destructive Tool for the Characterization of very thin films”, Thin Solid films, Vol. 154, 1987, pp. 217–223.Google Scholar
2. Rogers, J.A. et al. “Optical Generation and Characterization of Acoustic Waves in Thin Films”, Annual Review Material Science 2000, Vol. 30, pp. 117–157.Google Scholar
3. Qiu, T.Q. and Tien, C.L., “Short-Pulse Laser Heating on Metals”, International Journal of Heat Mass Transfer, Vol. 35, No.3, 1992, pp. 719–726.Google Scholar