Dislocations and elastic anisotropy in heteroepitaxial metallic thin films

• Published in: Philosophical magazine letters Vol. 83; no. 5; pp. 303 - 313
• Main Authors: Groh, S., Devincre, B., Kubin, L. P., Roos, A., Feyel, F., Chaboche, J.-L.
• Format: Journal Article
• Language: English
• Published: London Taylor & Francis Group 01.05.2003; Taylor & Francis
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Mechanical and acoustical properties; Metals. Metallurgy; Physical properties of thin films, nonelectronic; Physics; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Gold; Epitaxial layers; Elasticity; Theoretical study; Solid-solid interfaces; Dislocations; Thin films; Thickness; Stress relaxation; Anisotropy; Transition elements; Plasticity; Heteroepitaxy; Boundary-value problems; Nickel; Copper
• ISSN: 0950-0839; 1362-3036
• DOI: 10.1080/0950083032000069249

The influence of elastic anisotropy on the critical thickness for the plastic relaxation of epitaxial layers is examined with the help of a coupled discrete-continuum simulation. The latter incorporates a rigorous treatment of the boundary conditions and of mismatch stresses, as well as the elastic properties of a single threading dislocation. Numerical experiments conducted on model Cu/Cu, Cu/Au and Cu/Ni systems with a (001) interface show that, through several distinct effects, elastic anisotropy induces a significant increase in the critical thickness with respect to the values predicted by Matthews et al. The isotropic model of a comparison of the anisotropic critical thicknesses for (001) and (111) interfaces shows that Cu-(111) films on Ni substrates are about 50% 'harder' than (001) films. This feature is discussed in relation to the strength of thin metallic films.