Initial stage of layer‐by‐layer sputtering of Si(111) surfaces studied by scanning reflection electron microscopy

1996 ◽  
Vol 68 (18) ◽  
pp. 2514-2516 ◽  
Author(s):  
Heiji Watanabe ◽  
Masakazu Ichikawa
Keyword(s):  
Electron Microscopy ◽  
Layer By Layer ◽  
Initial Stage ◽  
Reflection Electron Microscopy

Observation of oxide/Si(001)-interface during layer-by-layer oxidation by scanning reflection electron microscopy

1997 ◽  
Vol 71 (7) ◽  
pp. 885-887 ◽  
Author(s):  
S. Fujita ◽  
H. Watanabe ◽  
S. Maruno ◽  
M. Ichikawa ◽  
T. Kawamura
Keyword(s):  
Electron Microscopy ◽  
Layer By Layer ◽  
Reflection Electron Microscopy

Vacancy Diffusion Kinetics on Si(111) and (001) Surfaces Studied by Scanning Reflection Electron Microscopy

1996 ◽  
Vol 440 ◽  
Author(s):  
Heiji Watanabe ◽  
Masakazu Ichikawa
Keyword(s):  
Electron Microscopy ◽  
Activation Energy ◽  
Ion Irradiation ◽  
Layer By Layer ◽  
Vacancy Diffusion ◽  
Island Nucleation ◽  
Reflection Electron Microscopy ◽  
Ion Impact ◽  
Step Flow Growth ◽  
Step Edges

AbstractThe kinetics of vacancy diffusion on Si(111) and (001) surfaces are studied by using scanning reflection electron microscopy (SREM). Two types of layer-by-layer etching (reversal of step-flow growth and two-dimensional vacancy island nucleation) are observed during lowenergy Ar ion irradiation (500 eV) at elevated substrate temperatures. This means that vacancies created by low-energy ion impact diffuse on the surfaces, and are annihilated at the step edges. Although isotropic vacancy diffusion is observed on Si(111), anisotropic vacancy diffusion along the dimer rows and preferential vacancy annihilation at the SB steps are observed on Si(001). This anisotropic vacancy diffusion results in single-domain formation. The diffusion length of vacancies is estimated from the width of the denuded zones, which are formed on both sides of the atomic steps by thermal heating after the introduction of vacancies at room temperature. The activation energy of 3.0±0.2 eV obtained for Si(111) corresponds to the potential barrier both for surface adatom diffusion and for lateral binding energy to release adatoms from the step edges. For Si(001) surfaces, the activation energy obtained for vacancy diffusion along the dimer rows is 2.3±0.2 eV. The vacancy diffusion model mediated by dimer vacancy complexes, rather than by single-dimer vacancies, best accounts for our experimental results.

Reflection electron microscopy of surfaces

1986 ◽  
Vol 44 ◽  
pp. 376-379
Author(s):  
G. Lehmpfuhl ◽  
Y. Uchida
Keyword(s):  
Electron Microscopy ◽  
Surface Topography ◽  
Single Crystals ◽  
Surface Science ◽  
Surface Treatments ◽  
Surface Steps ◽  
Transmission Electron ◽  
Initial Stage ◽  
Bulk Single Crystals ◽  
Reflection Electron Microscopy

In surface science the direct imaging of the surface topography of single crystals is of great interest for the investigation of surface-changing processes. Imaging can be done in transmission electron microscopy (TEM) as well as in reflection electron microscopy (REM) using a diffracted beam with surface-sensitive intensity. Surface steps of atomic height can be imaged with both methods. The highest resolution is obtainable only in transmission; however, for the investigation of surface treatments, the reflection method from bulk single crystals is more suitable, even with a lack of resolution, since the thin TEM specimens are often not mechanically stable against surface treatments. With this technique the initial stage of epitaxy, the influence of surface reactions, corrosion etc. on the surface topography can be investigated. The application of REM requires that two important conditions be met, one concerning the specimen itself. Due to the small angle of observation the image is foreshortened.

Studies of Oxide Formation on Copper Thin Films by Electron Microscopy

1977 ◽  
Vol 35 ◽  
pp. 316-317
Author(s):  
G. G. Hembree ◽  
M. A. Otooni ◽  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Electron Diffraction ◽  
Single Crystal ◽  
Crystal Surface ◽  
Crystal Defects ◽  
Diffraction Reflection ◽  
Reaction Products ◽  
Intermediate Energies ◽  
Crystal Films ◽  
Reflection Electron Microscopy

The formation of oxide structures on single crystal films of metals has been investigated using the REMEDIE system (for Reflection Electron Microscopy and Electron Diffraction at Intermediate Energies) (1). Using this instrument scanning images can be obtained with a 5 to 15keV incident electron beam by collecting either secondary or diffracted electrons from the crystal surface (2). It is particularly suited to studies of the present sort where the surface reactions are strongly related to surface morphology and crystal defects and the growth of reaction products is inhomogeneous and not adequately described in terms of a single parameter. Observation of the samples has also been made by reflection electron diffraction, reflection electron microscopy and replication techniques in a JEM-100B electron microscope.A thin single crystal film of copper, epitaxially grown on NaCl of (100) orientation, was repositioned on a large copper single crystal of (111) orientation.

Zero-loss omega-filtered REM and RHEED on the new Zeiss 912

1991 ◽  
Vol 49 ◽  
pp. 616-617
Author(s):  
J.C.H. Spence ◽  
J. Mayer
Keyword(s):  
Electron Microscopy ◽  
Materials Science ◽  
Surface States ◽  
Ccd Camera ◽  
Dark Field ◽  
Ion Pump ◽  
Magnetic Imaging ◽  
Reflection Electron Microscopy ◽  
Diffraction Patterns ◽  
Large Background

The Zeiss 912 is a new fully digital, side-entry, 120 Kv TEM/STEM instrument for materials science, fitted with an omega magnetic imaging energy filter. Pumping is by turbopump and ion pump. The magnetic imaging filter allows energy-filtered images or diffraction patterns to be recorded without scanning using efficient parallel (area) detection. The energy loss intensity distribution may also be displayed on the screen, and recorded by scanning it over the PMT supplied. If a CCD camera is fitted and suitable new software developed, “parallel ELS” recording results. For large fields of view, filtered images can be recorded much more efficiently than by Scanning Reflection Electron Microscopy, and the large background of inelastic scattering removed. We have therefore evaluated the 912 for REM and RHEED applications. Causes of streaking and resonance in RHEED patterns are being studied, and a more quantitative analysis of CBRED patterns may be possible. Dark field band-gap REM imaging of surface states may also be possible.

The annealed (0001) α-alumina surface and its influence on thin-film growth

1995 ◽  
Vol 53 ◽  
pp. 336-337
Author(s):  
Michael W. Bench ◽  
Paul G. Kotula ◽  
C. Barry Carter
Keyword(s):  
Electron Microscopy ◽  
Surface Energy ◽  
Film Growth ◽  
Thin Film Growth ◽  
Energy Calculations ◽  
Transmission Electron ◽  
Reflection Electron Microscopy ◽  
Low Energy Electron ◽  
Surface Nature

The growth of semiconductors, superconductors, metals, and other insulators has been investigated using alumina substrates in a variety of orientations. The surface state of the alumina (for example surface reconstruction and step nature) can be expected to affect the growth nature and quality of the epilayers. As such, the surface nature has been studied using a number of techniques including low energy electron diffraction (LEED), reflection electron microscopy (REM), transmission electron microscopy (TEM), molecular dynamics computer simulations, and also by theoretical surface energy calculations. In the (0001) orientation, the bulk alumina lattice can be thought of as a layered structure with A1-A1-O stacking. This gives three possible terminations of the bulk alumina lattice, with theoretical surface energy calculations suggesting that termination should occur between the Al layers. Thus, the lattice often has been described as being made up of layers of (Al-O-Al) unit stacking sequences. There is a 180° rotation in the surface symmetry of successive layers and a total of six layers are required to form the alumina unit cell.

SREM observation of the interaction between the in-situ deposited Pd small particles and MgO cleavage surface

1986 ◽  
Vol 44 ◽  
pp. 382-383
Author(s):  
H.-J. Ou
Keyword(s):  
Electron Microscopy ◽  
Small Particle ◽  
Small Particles ◽  
Cleavage Surface ◽  
Metallic Particles ◽  
Microscopy Technique ◽  
Ceramic Surfaces ◽  
Reflection Electron Microscopy ◽  
New Perspective

The understanding of the interactions between the small metallic particles and ceramic surfaces has been studied by many catalyst scientists. We had developed Scanning Reflection Electron Microscopy technique to study surface structure of MgO hulk cleaved surface and the interaction with the small particle of metals. Resolutions of 10Å has shown the periodic array of surface atomic steps on MgO. The SREM observation of the interaction between the metallic particles and the surface may provide a new perspective on such processes.

Parabolas from Reconstructed Surfaces Observed in Convergent-Beam RHEED Patterns

1990 ◽  
Vol 48 (2) ◽  
pp. 398-399
Author(s):  
M. Gajdardziska-Josifovska
Keyword(s):  
Electron Microscopy ◽  
High Energy ◽  
Two Dimensional ◽  
High Energy Electron ◽  
Reflection And Transmission ◽  
Experimental Diffraction Pattern ◽  
Surface Resonance ◽  
Reconstructed Surfaces ◽  
Reflection Electron Microscopy ◽  
Convergent Beam

Parabolas have been observed in the reflection high-energy electron diffraction (RHEED) patterns from surfaces of single crystals since the early thirties. In the last decade there has been a revival of attempts to elucidate the origin of these surface parabolas. The renewed interest stems from the need to understand the connection between the parabolas and the surface resonance (channeling) condition, the latter being routinely used to obtain higher intensity in reflection electron microscopy (REM) images of surfaces. Several rather diverging descriptions have been proposed to explain the parabolas in the reflection and transmission Kikuchi patterns. Recently we have developed an unifying general treatment in which the parabolas are shown to be K-lines of two-dimensional lattices. Here we want to review the main features of this description and present an experimental diffraction pattern from a 30° MgO (111) surface which displays parabolas that can be attributed to the surface reconstruction.

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