Quantitative analysis of the deformation and chemical profiles of strained multilayers

Strain Measurement in Semiconductor Heterostructures by Scanning Transmission Electron Microscopy

“…can be divided in two groups-imaging and diffraction. The former originally exploits atomically resolved TEM micrographs with respect to lattice fringe distances~Bierwolf Bayle et al, 1994;Jouneau et al, 1994;Robertson et al, 1995;Rosenauer et al, 1998!. As the observed high-resolution pattern is formed by the interference of all diffracted beams passing the objective aperture, subsequent studies included partly extensive analysis of the phases of Bragg beams as a function of specimen thickness, orientation, composition, crystal potential Fourier components, lens aberrations, and defocus~Tillmann et al, 2000;Hÿtch & Plamann, 2001;Rosenauer et al, 2001;Rosenauer et al, 2006;Guerrero et al, 2007;Müller et al, 2010;Yu & Mader, 2010!. One disadvantage common to all high-resolution TEM techniques is the restricted field of view not only because the lattice fringe pattern must be sampled densely enough to measure fringe spacings precisely, but also because measured fringe distances need to be normalized tõ substrate! regions with known strain state, which may be too far away from the region of interest.…”

Influence of Imaging Parameters and Specimen Thinning on Strain Measurements in Au/Ni MBE Multilayers by HREM Image Processing

“…Distortion profiles along the growth direction were measured using image processing on HREM micrographs. In Section 2, we summarize the method used to quantify this distortion and the experimental results already presented in details in reference [1]. The distortion profiles were measured for Ni layers thinner than 5 ML ( i. e. in the coherent growth régime).…”

“…In our case, we determined the accurate positions of the intensity maxima by a recursive centre of mass extraction [1,6]. The [7].…”

Analysis of Variations in Structure from High Resolution Electron Microscope Images by Combining Real Space and Fourier Space Information

“…The bulk lattice parameter of Ni is 14% less than that of Au so we would expect to see variations in the lattice fringe spacings in the image. Similar strained multilayers have been analysed by marking the positions of the peaks in intensity in the image, the separation of the peaks giving the local lattice fringe parameter [18][19][20]. The phase images should provide similar information given the relationship between the gradient of the phase and the local difference in reciprocal lattice fringe vector.…”

“…7). The correct procedure is therefore to obtain a good first estimate of the composition profile from the experimental image, model the layer system taking into account such effects as relaxation [19], and compare the simulations with the experimental data, refining the model as necessary [20].…”