Published online by Cambridge University Press: 01 February 2011
Epitaxial TiN/Cu bilayers and multilayers with periods L between 5 and 50 nm have been grown by ultrahigh vacuum ion beam sputtering on Si and MgO(001) substrates at room temperature. The deformation modes induced by a Berkovich nanoindent have been imaged using Focused Ion Beam – Transmission Electron Microscopy (FIB-TEM) and Atomic Force Microscopy (AFM). The observations suggest that the mechanical response of the multilayers is essentially governed by an extensive plastic flow inside the Cu layers, which is confined by a bending of the more rigid TiN layers. This specific deformation behavior, with no contribution of the interfaces as a barrier for dislocation motion could explain the absence of significant hardness enhancement in this system.