Imaging Dislocations in Single-Crystal SrTiO3 Substrates by Electron Channeling

Abstract

Electron channeling contrast imaging (ECCI) using a conventional polemounted backscatter detector in a commercial scanning electron microscope (SEM) has been implemented to analyze extended defects. In-grown extended defects in bulk SrTiO 3 (001) substrates such as dislocation loops, subsurface dislocations parallel to the surface, and surface-penetrating dislocations have been distinguished by ECCI. The techniques of dislocation-selective etching and ECCI have been compared side-by-side, where surface-penetrating dislocations have been shown to have one-to-one correspondence with ECCI spot features. gAEb and gAEb 9 u have been implemented for subsurface portions of intrinsic dislocations, being identified as screw dislocations with Burgers vector in the h100i direction.

Nanoscale studies of ferroelectric domain walls as pinned elastic interfaces

“…6(e)). Transmission and scanning electron microscopy studies of selectively etched single crystal SrTiO 3 revealed dislocation densities of ∼10 8 cm −2 [140,141], qualitatively in agreement with the observed disorder fluctuations. The ability to non-invasively identify these very localised features at the domain walls could be especially interesting when coupled with an investigation of their functional properties [74].…”

Defect Analysis in La0.7Sr0.3MnO3 Epitaxial Thin Films by Electron Channeling Contrast Imaging (ECCI)

“…X-ray diffraction (XRD) provides averages over a large scale and requires significant calibration. Electron channeling contrast imaging (ECCI), however, offers a straightforward and non-destructive way to image extended defects over micron length scales; recent examples include dislocation imaging in semiconductors (GaN) [1] and perovskite oxides (SrTiO 3 ) [2].In this study, ECCI is employed to investigate defects associated with misfit strains in epitaxial La 0.7 Sr 0.3 MnO 3 (LSM) thin films. LSM adopts the perovskite structure and possesses many interesting properties, such as ferromagnetism, colossal magnetic resistance (CMR), and excellent oxygen exchange properties for solid oxide fuel cell (SOFC) cathodes.…”

“…X-ray diffraction (XRD) provides averages over a large scale and requires significant calibration. Electron channeling contrast imaging (ECCI), however, offers a straightforward and non-destructive way to image extended defects over micron length scales; recent examples include dislocation imaging in semiconductors (GaN) [1] and perovskite oxides (SrTiO 3 ) [2].…”

“…These line features exhibit unusual morphologies and unexpected contrast behavior with respect to diffraction conditions. They indicate the presence of extended structural defects in LSM, possibly closed dislocation loops (observed in SrTiO 3 [2]), anti-phase boundaries of 2D islands, or domain boundaries of twin structures [4]. Coordinated ECCI and high-resolution TEM with chemical composition analysis will be presented along with computational models of ECCI contrast from these defects.…”

Electron channeling contrast imaging studies of nonpolar nitrides using a scanning electron microscope

“…29) and SrTiO 3 . 30 In ECCI, images are produced from electrons which channel down the crystal planes of a suitably oriented sample. Changes in crystallographic orientation, or in lattice constant due to local strain, are revealed by changes in contrast in a channeling image constructed by monitoring the intensity of backscattered electrons as the electron beam is scanned over the sample.…”