Rapid low dose electron tomography using a direct electron detection camera

Migunov, Vadim; Ryll, H.; Zhuge, Xiaodong; Simson, M.; Strüder, L.; Batenburg, K. Joost; Houben, Lothar; Dunin-Borkowski, Rafal E.

doi:10.1038/srep14516

Cited by 76 publications

(58 citation statements)

References 26 publications

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“…However, the required depth information in the electron beam direction is not available at present. The advent of fast 3D tomography [19] promises to allow three-dimensional information about such conductive channels to be revealed. Interestingly, even for voltages below 5 V, when a negligible current is measured, a remaining area of dark contrast is present at the TiN-SiO x interface, suggesting that part of the SiO x layer remains conducting in the absence of an applied voltage.…”

Section: Resultsmentioning

confidence: 99%

In situ transmission electron microscopy of resistive switching in thin silicon oxide layers

Duchamp¹,

Migunov²,

Tavabi³

et al. 2016

Resolution and Discovery

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Silicon oxide-based resistive switching devices show great potential for applications in nonvolatile random access memories. We expose a device to voltages above hard breakdown and show that hard oxide breakdown results in mixing of the SiO x layer and the TiN lower contact layers. We switch a similar device at sub-breakdown fields in situ in the transmission electron microscope (TEM) using a movable probe and study the diffusion mechanism that leads to resistance switching. By recording bright-field (BF) TEM movies while switching the device, we observe the creation of a filament that is correlated with a change in conductivity of the SiO x layer. We also examine a device prepared on a microfabricated chip and show that variations in electrostatic potential in the SiO x layer can be recorded using off-axis electron holography as the sample is switched in situ in the TEM. Taken together, the visualization of compositional changes in ex situ stressed samples and the simultaneous observation of BF TEM contrast variations, a conductivity increase, and a potential drop across the dielectric layer in in situ switched devices allow us to conclude that nucleation of the electroforming-switching process starts at the interface between the SiO x layer and the lower contact.

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Section: Resultsmentioning

confidence: 99%

In situ transmission electron microscopy of resistive switching in thin silicon oxide layers

Duchamp¹,

Migunov²,

Tavabi³

et al. 2016

Resolution and Discovery

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“…Although ultra-low-dose electron tomography with a temporal resolution of 3.5 s has been demonstrated in lanthanides, 56 there are few studies on polymeric systems. The total accumulated dose for this in situ experiment was 8 e − /Å 2 , which is much lower than that used for polymer 3D-TEM experiments.…”

Section: Electron Tomography Of Unstained Bcp Specimen Toward In Situmentioning

confidence: 99%

Three-Dimensional Visualization and Characterization of Polymeric Self-Assemblies by Transmission Electron Microtomography

et al. 2017

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* S Supporting Information CONSPECTUS: Self-assembling structures and their dynamical processes in polymeric systems have been investigated using three-dimensional transmission electron microscopy (3D-TEM). Block copolymers (BCPs) self-assemble into nanoscale periodic structures called microphase-separated structures, a deep understanding of which is important for creating nanomaterials with superior physical properties, such as high-performance membranes with well-defined pore size and high-density data storage media. Because microphase-separated structures have become increasingly complicated with advances in precision polymerization, characterizing these complex morphologies is becoming increasingly difficult. Thus, microscopes capable of obtaining 3D images are required. In this article, we demonstrate that 3D-TEM is an essential tool for studying BCP nanostructures, especially those self-assembled during dynamical processes and under confined conditions. The first example is a dynamical process called order−order transitions (OOTs). Upon changing temperature or pressure or applying an external field, such as a shear flow or electric field, BCP nanostructures transform from one type of structure to another. The OOTs are examined by freezing the specimens in the middle of the OOT and then observing the boundary structures between the preexisting and newly formed nanostructures in three-dimensions. In an OOT between the bicontinuous double gyroid and hexagonally packed cylindrical structures, two different types of epitaxial phase transition paths are found. Interestingly, the paths depend on the direction of the OOT. The second example is BCP self-assemblies under confinement that have been examined by 3D-TEM. A variety of intriguing and very complicated 3D morphologies can be formed even from the BCPs that self-assemble into simple nanostructures, such as lamellar and cylindrical structures in the bulk (in free space). Although 3D-TEM is becoming more frequently used for detailed morphological investigations, it is generally used to study static nanostructures. Although OOTs are dynamical processes, the actual experiment is done in the static state, through a detailed morphological study of a snapshot taken during the OOT. Developing time-dependent nanoscale 3D imaging has become a hot topic. Here, the two main problems preventing the development of in situ electron tomography for polymer materials are addressed. First, the staining protocol often used to enhance contrast for electrons is replaced by a new contrast enhancement based on chemical differences between polymers. In this case, no staining is necessary. Second, a new 3D reconstruction algorithm allows us to obtain a high-contrast, quantitative 3D image from fewer projections than is required for the conventional algorithm to achieve similar contrast, reducing the number of projections and thus the electron beam dose. Combining these two new developments is expected to open new doors to 3D in situ real-time structural observation of polymer materials.

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“…Although ultrafast cameras89101112131415 are currently introduced to the field of low-angle STEM, our approach exhibits several advantages. As quantitative analyses of atomically resolved STEM intensities rely on Voronoi diagrams16, Gaussian mixture models1718 or probe integrated cross sections19, each atomic column must be sampled with a sufficient number of probe positions.…”

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confidence: 99%

Materials characterisation by angle-resolved scanning transmission electron microscopy

Müller‐Caspary

Oppermann

Grieb

et al. 2016

Sci Rep

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Solid-state properties such as strain or chemical composition often leave characteristic fingerprints in the angular dependence of electron scattering. Scanning transmission electron microscopy (STEM) is dedicated to probe scattered intensity with atomic resolution, but it drastically lacks angular resolution. Here we report both a setup to exploit the explicit angular dependence of scattered intensity and applications of angle-resolved STEM to semiconductor nanostructures. Our method is applied to measure nitrogen content and specimen thickness in a GaNxAs1−x layer independently at atomic resolution by evaluating two dedicated angular intervals. We demonstrate contrast formation due to strain and composition in a Si- based metal-oxide semiconductor field effect transistor (MOSFET) with GexSi1−x stressors as a function of the angles used for imaging. To shed light on the validity of current theoretical approaches this data is compared with theory, namely the Rutherford approach and contemporary multislice simulations. Inconsistency is found for the Rutherford model in the whole angular range of 16–255 mrad. Contrary, the multislice simulations are applicable for angles larger than 35 mrad whereas a significant mismatch is observed at lower angles. This limitation of established simulations is discussed particularly on the basis of inelastic scattering.

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Rapid low dose electron tomography using a direct electron detection camera

Cited by 76 publications

References 26 publications

In situ transmission electron microscopy of resistive switching in thin silicon oxide layers

In situ transmission electron microscopy of resistive switching in thin silicon oxide layers

Three-Dimensional Visualization and Characterization of Polymeric Self-Assemblies by Transmission Electron Microtomography

Materials characterisation by angle-resolved scanning transmission electron microscopy

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