High-resolution transmission electron microscopy: A structural and chemical probe of semiconductor systems

1987 ◽  
Vol 45 ◽  
pp. 332-333
Author(s):  
A. Ourmazd
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Structural Information ◽  
Image Interpretation ◽  
Lattice Image ◽  
Semiconductor Interfaces ◽  
Transmission Electron ◽  
Lattice Images ◽  
The Individual

High Resolution Transmission Electron Microscopy (HRTEM) is now a powerful probe for the structural analysis of semiconductor systems. Lattice images can be obtained in a number of orientations, in at least three of which the individual atomic columns can be resolved. However, there exits an important class of problems, whose resolution requires chemical as well as structural information. The identification of individual atomic columns in compound semiconductors, and the atomic configuration of semiconductor/semiconductor interfaces are two important examples.In general, most reflection used to form a lattice image are not particularly sensitive to chemical changes in the sample. The information content of a typical lattice image is therefore strongly dominated by structural details. On the other hand, reflections such as the (200), which are normally forbidden in the diamond structure, come about in the zinc-blende system because of the chemical differences between the occupants of the two sublattices, and are thus highly chemically sensitive. In the “kinematical” thickness region, where simple image interpretation is possible, such reflections are relatively weak and their contribution to the lattice image is dominated by the stronger and chemically insensitive, allowed reflections.

Quantitative Investigations of Interfaces and Grain Boundaries by Phase Contrast Electron Microscopy with Ultra High Resolution

2001 ◽  
Vol 7 (S2) ◽  
pp. 288-289
Author(s):  
C. Kisielowski ◽  
J.M. Plitzko ◽  
S. Lartigue ◽  
T. Radetic ◽  
U. Dahmen
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Phase Contrast ◽  
Recent Progress ◽  
Image Interpretation ◽  
Present Contribution ◽  
Crystalline Materials ◽  
Transmission Electron ◽  
Contrast Microscopy ◽  
Lattice Images

Recent progress in High Resolution Transmission Electron Microscopy makes it possible to investigate crystalline materials by phase contrast microscopy with a resolution close to the 80 pm information limit of a 300 kV field emission microscope'"". A reconstruction of the electron exit wave from a focal series of lattice images converts the recorded information into interpretable resolution. The present contribution illustrates some recent applications of this technique to interfaces.Fig. 1 shows a reconstructed electron exit wave of a heterophase interface between GaN and sapphire. The experiment takes advantage of three factors: First, we resolved the GaN lattice in projection, which requires at least 0.15 nm resolution. The projection eliminates the stacking fault contrast that usually obscures lattice images in the commonly recorded projection. Thus, image interpretation is drastically simplified. Second, all atom columns at the interface and in the sapphire are resolvable with a smallest projected aluminum - oxygen spacing of 85 pm in the sapphire.

Structural study of Cd(S,Se) doped glasses. High-resolution transmission electron microscopy (HRTEM) assisted by image processing

1990 ◽  
Vol 23 (5) ◽  
pp. 418-423 ◽  
Author(s):  
M. Allais ◽  
M. Gandais
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Bulk Material ◽  
Optical Filters ◽  
Characteristic Size ◽  
Transmission Electron ◽  
Doped Glasses ◽  
Lattice Images ◽  
Average Size

High-resolution transmission electron microscopy (HRTEM) was used for examining Cd(S,Se) nanocrystals grown in silicate glasses commercially available as optical filters. The lattice images of the nanocrystals were numerated and submitted to filtering through Fourier transformation in order to sweep off the background signal originating mainly from glass. Optical filters from several firms were examined. The nanocrystals have been identified with Cd(S,Se) compounds crystallized in the wurzite structure, as in bulk material. The lattice images indicate crystallites having the shape of hexagonal prisms a little elongated along the c axis. The distribution of grain size differs according to the filter: the smallest size being about 1.5 nm (threshold for detection), the largest size varies from 7 to 10 nm, the average size sa , from 3–4 to 5–6 nm and the characteristic size sc from 5–6 to 7–8 nm (sc is the size of grains occupying the main part of the crystallized volume).

scholarly journals Single-particle cryo-EM: alternative schemes to improve dose efficiency

2021 ◽  
Vol 28 (5) ◽  
pp. 1343-1356
Author(s):  
Yue Zhang ◽  
Peng-Han Lu ◽  
Enzo Rotunno ◽  
Filippo Troiani ◽  
J. Paul van Schayck ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Radiation Damage ◽  
Information Transfer ◽  
Structural Information ◽  
High Energy ◽  
Phase Plate ◽  
Transmission Electron ◽  
Dose Efficiency ◽  
The Individual

Imaging of biomolecules by ionizing radiation, such as electrons, causes radiation damage which introduces structural and compositional changes of the specimen. The total number of high-energy electrons per surface area that can be used for imaging in cryogenic electron microscopy (cryo-EM) is severely restricted due to radiation damage, resulting in low signal-to-noise ratios (SNR). High resolution details are dampened by the transfer function of the microscope and detector, and are the first to be lost as radiation damage alters the individual molecules which are presumed to be identical during averaging. As a consequence, radiation damage puts a limit on the particle size and sample heterogeneity with which electron microscopy (EM) can deal. Since a transmission EM (TEM) image is formed from the scattering process of the electron by the specimen interaction potential, radiation damage is inevitable. However, we can aim to maximize the information transfer for a given dose and increase the SNR by finding alternatives to the conventional phase-contrast cryo-EM techniques. Here some alternative transmission electron microscopy techniques are reviewed, including phase plate, multi-pass transmission electron microscopy, off-axis holography, ptychography and a quantum sorter. Their prospects for providing more or complementary structural information within the limited lifetime of the sample are discussed.

Preparation of vermiculites for HRTEM

Clay Minerals ◽  
1989 ◽  
Vol 24 (1) ◽  
pp. 23-32 ◽  
Author(s):  
CH. Marcks ◽  
H. Wachsmuth ◽  
H. Graf V. Reichenbach
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Computer Simulation ◽  
High Resolution ◽  
Alkyl Chains ◽  
Transmission Electron ◽  
Lattice Images ◽  
Silicate Layers

AbstractA technique for preparing vermiculites for examination by high-resolution transmission electron microscopy (HRTEM) has been developed. A TEM-stable expanded phase can be obtained by intercalating n-alkylammonium ions between the silicate layers of a parent biotite. The vermiculite particles were embedded in Spurr resin and centrifuged to improve orientation. Ultra-thin specimens were prepared using an ultramicrotome, the quality and thickness of the sections being monitored by TEM. Lattice images of biotite, Ba-vermiculite and octylammonium-vermiculite, the latter showing a perpendicular arrangement of the alkyl chains relative to the silicate layers, were obtained with a resolution ∼2 Å. The reliability of these images was confirmed by computer simulation.

scholarly journals Recent Advances in Electron Tomography: TEM and HAADF-STEM Tomography for Materials Science and Semiconductor Applications

2005 ◽  
Vol 11 (5) ◽  
pp. 378-400 ◽  
Author(s):  
Christian Kübel ◽  
Andreas Voigt ◽  
Remco Schoenmakers ◽  
Max Otten ◽  
David Su ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Structural Information ◽  
Electron Tomography ◽  
Semiconductor Devices ◽  
Three Dimensional ◽  
Crystalline Materials ◽  
Transmission Electron ◽  
Stem Tomography

Electron tomography is a well-established technique for three-dimensional structure determination of (almost) amorphous specimens in life sciences applications. With the recent advances in nanotechnology and the semiconductor industry, there is also an increasing need for high-resolution three-dimensional (3D) structural information in physical sciences. In this article, we evaluate the capabilities and limitations of transmission electron microscopy (TEM) and high-angle-annular-dark-field scanning transmission electron microscopy (HAADF-STEM) tomography for the 3D structural characterization of partially crystalline to highly crystalline materials. Our analysis of catalysts, a hydrogen storage material, and different semiconductor devices shows that features with a diameter as small as 1–2 nm can be resolved in three dimensions by electron tomography. For partially crystalline materials with small single crystalline domains, bright-field TEM tomography provides reliable 3D structural information. HAADF-STEM tomography is more versatile and can also be used for high-resolution 3D imaging of highly crystalline materials such as semiconductor devices.

Crystalline Particles in Thermally Grown Silicon Dioxide

1982 ◽  
Vol 14 ◽  
Author(s):  
F. A. Ponce ◽  
T. Yamashita
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Silicon Dioxide ◽  
Silicon Layer ◽  
Orientation Relationships ◽  
Transmission Electron ◽  
Lattice Images ◽  
Thermally Grown

ABSTRACTSmall crystalline particles in the vicinity of the Si/SiO2 interface have been directly observed by high resolution transmission electron microscopy. These crystallites have typical diameters between 20 and 120 Å. Based on the observed interplanar spacings and angles in lattice images, the structure of these particles has been found to match those of cristobalite. Some orientation relationships also appear to exist between these particles and the silicon layer.

Sign in / Sign up

Export Citation Format

Share Document