Transmission Electron Microscopy of Multilayer Thin Films

Abstract

The unique geometry of multilayer thin films, with layer thicknesses on the nanoscale, gives rise to a wide range of novel properties and behavior that are not observed in the bulk. The novel behavior is critically dependent on the microstructure of the films. This paper reviews the use of a range of transmission electron microscopy (TEM) techniques to elucidate the structure, chemistry, and properties of multilayer thin films. The paper includes a brief introduction to the technological applications to which multilayer thin films are suited, followed by a description of the various TEM techniques. The final section of the paper presents the application of these techniques to various multilayer thin film systems. 559

Size effect on mechanical behavior of Al/Si3N4 multilayers by nanoindentation

“…Nanoscale multilayered composites exhibit distinct electrical [1][2][3], magnetic [4], optical [5,6] and mechanical properties [7][8][9][10], and therefore have attracted an increased research attention for more than a decade [11][12][13][14][15][16]. Increasing interest is also paid on the investigation of mechanical properties of the multilayered composites due to the implication on the reliability issue in the applications.…”

High-resolution characterization of TiN diffusion barrier layers

“…Moreover, the structure factor of the investigated material has to be considered, which accounts for atomic positions in the unit cell, and can modulate or completely cancel some reflections in the diffraction pattern [8,101,102]. Strong TEM diffraction contrast can be achieved under so-called two-beam conditions, where in addition to the direct beam only one diffracted beam is strongly excited by tilting the specimen.…”

“…Sample regions containing heavier atoms will appear brighter in the resulting dark-field image ( Fig. 12(b)) [8,101,102]. A further advantage of HAADF imaging is that the contrast is usually insensitive to small changes in defocus or specimen thickness.…”

“…Thus, an image related directly to the structural periodicity of the crystalline specimen (but not necessarily to the real position of an atom!) is formed in the IP, where the direct and diffracted beams interfere again [8,102]. .…”

“…Reciprocal space information can be obtained at the same spatial location and gives further insights into crystallographic orienta-tion relationships at interfaces. Moreover, elemental mapping and Z (atomic number)-contrast imaging allow for the visualization of diffusion across the barrier layer [8]. In the past years another technique, atom probe tomography (APT), has gained acclaim as a tool offering true 3D characterization at the nanoscale.…”