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Laser-acoustic method for determining Young's modulus of thin films

Die Laserakustikmethode zur Bestimmung des Elastizitätsmodules dünner Schichten
: Schneider, D.

Oettel, H. ; Graduiertenkolleg Werkstoffphysikalische Modellierung, Freiberg:
Mechanical behaviour of PVD coated materials. Proceedings of the International Workshop
Freiberg: TU Bergakademie, 1998 (Freiberger Forschungshefte. B 287)
ISBN: 3-86012-053-0
pp.77-82 : Ill., Lit.
International Workshop Mechanical Behaviour of PVD Coated Materials <1997, Holzhau, Freiberg>
Conference Paper
Fraunhofer IWS ()

The laser-acoustic technique is a promising method to determine Young's modulus of thin films. Wide-band surface wave impulses are generated by short laser pulses and are detected with a piezoelectric transducer. Fourier transforming the acoustic signal provides the phase velocity depending on frequency. The measurement in the frequency range up to 200 MHz enables the Young's modulus of films with thickness less than 100 nm to be determined. Young's modulus of hard films proved to be a valuable parameter for characterizing thin films. It represents the stiffness of the material and is a measure for the inter-atomic bonding forces. The most theoretical relations derived for strength, adhesion, or hardness of films require the film modulus to be known. Therefore, correlation between these mechanical properties and the Young's modulus of the film have been found.