Scanning Reflection Electron Microscopy of 2x1 Domain Structure of Si(111) Surface

Author(s):  
H.-J. Ou

Studies of the surface structure of silicon with good spatial resolution made recently by reflection electron microscopy, (REM) have complemented and greatly extended the earlier studies, made by LEED and other methods, of the formation of surface reconstruction superstructures such a the Si(111) 7x7. These studies have not included the 2x1 superstructure on (111) surfaces formed by cleaving Si crystals in ultra-high vacuum. We have now investigated the form of the domains of this 2x1 structure by use of a reconstructed REMEDIE system 2.3 (for Reflection Electron Microscopy and Electron Diffraction at Intermediate Energies, 1-20keV). This system has shown a spatial resolution of better than 100Å although resolutions of about 300Å may be more common in practise because of the limitations due to probe size, vibration and signal noise.

Author(s):  
G. G. Hembree ◽  
M. A. Otooni ◽  
J. M. Cowley

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.


Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove

The silicides CoSi2 and NiSi2 are both metallic with the fee flourite structure and lattice constants which are close to silicon (1.2% and 0.6% smaller at room temperature respectively) Consequently epitaxial cobalt and nickel disilicide can be grown on silicon. If these layers are formed by ultra high vacuum (UHV) deposition (also known as molecular beam epitaxy or MBE) their thickness can be controlled to within a few monolayers. Such ultrathin metal/silicon systems have many potential applications: for example electronic devices based on ballistic transport. They also provide a model system to study the properties of heterointerfaces. In this work we will discuss results obtained using in situ and ex situ transmission electron microscopy (TEM).In situ TEM is suited to the study of MBE growth for several reasons. It offers high spatial resolution and the ability to penetrate many monolayers of material. This is in contrast to the techniques which are usually employed for in situ measurements in MBE, for example low energy electron diffraction (LEED) and reflection high energy electron diffraction (RHEED), which are both sensitive to only a few monolayers at the surface.


2003 ◽  
Vol 36 (6) ◽  
pp. 1319-1323 ◽  
Author(s):  
A. Morawiec

A method that improves the accuracy of misorientations determined from Kikuchi patterns is described. It is based on the fact that some parameters of a misorientation calculated from two orientations are more accurate than other parameters. A procedure which eliminates inaccurate elements is devised. It requires at least two foil inclinations. The quality of the approach relies on the possibility to set large sample-to-detector distances and the availability of good spatial resolution of transmission electron microscopy. Achievable accuracy is one order of magnitude better than the accuracy of the standard procedure.


1992 ◽  
Vol 295 ◽  
Author(s):  
M. R. Scheinfein ◽  
J. S. Drucker ◽  
J. Liu ◽  
J. K. Weiss ◽  
G. G. Hembree ◽  
...  

AbstractThe secondary electron generation process is studied in an ultra-high vacuum scanning transmission electron microscope using electron coincidence spectroscopy. Production pathways for secondary electrons are determined by analyzing coincidences between secondary electrons and individual excitation events. The ultimate spatial resolution available in scanning electron microscopy is limited by the delocalization of the secondary electron generation process. This delocalization is studied using momentum resolved coincidence electron spectroscopy. The fraction of secondary electrons resulting from localized excitations can explain the high spatial resolution observed in secondary electron microscopy images.


1975 ◽  
Vol 46 (7) ◽  
pp. 826 ◽  
Author(s):  
J. M. Cowley ◽  
J. L. Albain ◽  
G. G. Hembree ◽  
P. E. Ho̸jlund-Nielsen ◽  
F. A. Koch ◽  
...  

1994 ◽  
Vol 357 ◽  
Author(s):  
T. Wagner ◽  
M. Ruhle

AbstractThe A1/MgO system has been used as a model system to study growth processes and structure at metal/ceramic interfaces. Aluminum films were grown on air-cleaved MgO (100) substrates in ultra high vacuum (UHV) by molecular beam epitaxy (MBE). The substrates and films were characterized by reflection high energy electron diffraction (RHEED), x-ray diffraction (XRD), conventional transmission electron microscopy (CTEM), and high resolution transmission electron microscopy (HREM). XRD measurements exhibited a pronounced {100} texture. Employing electron diffraction in the TEM on cross sectional samples, we observed the following orientation relationship between Al and MgO: (100)A1 II (100)MgO; [010]A1 II [010]MgO. The atomistic structure of the interface was investigated by HREM. Regions of structural defects can be identified clearly at the interface.


Author(s):  
Tung Hsu ◽  
Sumio Iijima

Reflection electron microscopy (REM) in ultra high vacuum environment with heating stage has been reported by Osakabe, et al. In this paper, we present our results in REM imaging of single steps and dislocations using commercial electron microscopes (JEM-100B and Philips-400T) under ordinary pressure (10-7 torr) and room temperature.


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