Regensburg 1998 – wissenschaftliches Programm

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SYB: Symposium Elastische und plastische Eingenschaften dünner Filme

SYB 1: Elastische und plastische Eingenschaften dünner Filme

SYB 1.4: Hauptvortrag

Mittwoch, 25. März 1998, 16:00–16:30, H 32

Stress Evolution During Metal Thin Film and Multilayer Growth — •B.M. Clemens, V. Ramaswamy, J. Freitag, and W.D. Nix — Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305-2205

In order to understand the relationship between stress and the structural upheaveal accompanying the initial stages of growth, in situ stress measurements were performed during thin film and multilayer growth. A laser-based substrate curvature technique was used, giving sensitivity to measure stress changes associated with sub-monolayer coverages. The stress measurements were correlated with the results of microstructural measurements using atomic force microscopy and x-ray diffraction, including small angle scattering and superlattice diffraction simulation. Several multilayer systems, including Cu/Pd, Cu/Ni, Pt/Pd, and Mo/Si, were investigated over a range of bilayer periods from 1 to 10 nm.

The stress behavior is complex, with the evolution of the stress in a given layer depending on growth conditions as well as the thickness and condition of the layer below. In Mo/Si multilayers, the stress is opposite in sign in the two constituent layers, with Mo showing a sharp tensile stress up to about 1 nm and then almost unstressed behavior, while the Si shows a compressive stress behavior throughout its growth. This behavior reflects the large volume change associated with interfacial intermixing in this system. This behavior points to the importance of in situ tools for understanding the processes leading to stress in multilayer films.