A Study of FeAl/AlAs/GaAs Interfaces Using Moiré-Fringe Contrast in a Transmission Electron Microscope

1990 ◽  
Vol 202 ◽  
Author(s):  
J. E. Angelo ◽  
J.N. Kuznia ◽  
A.M. Wowchak ◽  
P. I. Cohen ◽  
W. W. Gerberich
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Growth Temperature ◽  
Growth Mode ◽  
Misfit Dislocations ◽  
Layer By Layer ◽  
Plan View ◽  
Transmission Electron ◽  
Moire Fringe ◽  
Moiré Fringe

ABSTRACTThis paper describes the transmission electron microscope (TEM) investigations of the defect structure present at various FeAl/AlAs/GaAs interfaces. Although a systematic study has not yet been completed it is shown that by changing the growth temperature from 200°C to 300°C the growth morphology changes significantly. In-situ RHEED studies show the growth mode changes from layer-by-layer to island-like when the growth temperature is increased. TEM in both plan-view and cross-sectional modes is used to confirm these results. It is found that by increasing the growth temperature from 200°C to 300°C the growth mode switches from layer-by-layer (2D) with a continuous FeAl film, to island-like (3D) with significant numbers of “pin-holes”. A Moiré-fringe analysis is applied to determine the Burgers vector of the misfit dislocations. In both cases the interface between the FeAl and AlAs consists of a grid of misfit dislocations with [100] and [010] line directions whose Burgers vectors are [010] and [100] respectively.

scholarly journals Sequential plan-view imaging of sub-surface structures in the transmission electron microscope

Materialia ◽  
2020 ◽  
Vol 12 ◽  
pp. 100798
Author(s):  
F.C-P. Massabuau ◽  
H.P. Springbett ◽  
G. Divitini ◽  
P.H. Griffin ◽  
T. Zhu ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Surface Structures ◽  
Plan View ◽  
Sequential Plan ◽  
Transmission Electron

A Technique for Preparing Transmission Electron Microscope Specimens Using Cleavage

1987 ◽  
Vol 115 ◽  
Author(s):  
T. Boone ◽  
S. Nakahara
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Cross Sections ◽  
Specimen Preparation ◽  
Plan View ◽  
Transmission Electron ◽  
Thinning Operation ◽  
Thin Electron ◽  
Reflection Electron Microscopy ◽  
Transparent Region

ABSTRACTA technique for observing both plan view and cross sections of a specimen directly in a transmission electron microscope (TEM) without relying on a tedious thinning operation was developed. This technique involves cleaving a specimen perpendicular to the plane, so that the thin (electron transparent) section of the cleaved edge can be directly imaged by TEM. The only limitations of this technique are that a specimen must be readily criacked or cleaved and that, since the transparent region is often bounded by a 90° corner, the extent of electron transparent region is somewhat localized. Nevertheless, the technique has the advantages of the ease of specimen preparation, and the absence of contamination or damage introduced in other conventional thinning methods. The geometry of the cleaved specimen is also suitable for reflection electron microscopy.

Cathodoluminescence from Inx Ga1−x as Layers Grown on GaAs Using a Transmission Electron Microscope

1999 ◽  
Vol 588 ◽  
Author(s):  
N. Yamamoto ◽  
T. Mita ◽  
S. Heun ◽  
A. Franciosi ◽  
J.-M. Bonard
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Strong Line ◽  
Wavelength Shift ◽  
Misfit Dislocations ◽  
Ion Milling ◽  
Thin Sample ◽  
Dark Line ◽  
Linear Features ◽  
Transmission Electron

AbstractInxGa1−xAs epilayers grown on GaAs(100) were studied by cathodoluminescence (CL) spectroscopy and imaging technique with 0.8 nm spectral resolution, using a transmission electron microscope. Linear features appear in the monochromatic CL image taken by the emission from the InxGa1−x.As layers, and do not appear in those from the GaAs layers. There is no direct correlation between the dark-line contrast in the panchromatic CL image (due to misfit dislocations) and the strong line contrast in the monochromatic CL images of the InxGa1−xAs layers. A peak wavelength shift in the CL spectrum was observed as the electron probe was moved across the linear features. The linear features also appear in a thin sample where the misfit dislocations are removed by ion milling, which clearly reveals that the strong line contrast is not directly due to the misfit dislocation. From those results the linear features in the monochromatic CL image are considered to be due to compositional fluctuations of the In concentration in the InxGa1−xAs layer.

scholarly journals Edge-On Ion Irradiation of Electron Microscope Specimens

1992 ◽  
Vol 268 ◽  
Author(s):  
Mauro P. Otero ◽  
Charles W. Allen
Keyword(s):  
Electron Microscope ◽  
Cross Section ◽  
Transmission Electron Microscope ◽  
Ion Irradiation ◽  
Special Technique ◽  
Plan View ◽  
Depth Direction ◽  
Transmission Electron ◽  
Foil Specimen

ABSTRACTA special technique is described for in situ transmission electron microscope (TEM) experiments involving simultaneous ion irradiation, in which the resultant phenomena are observed as in a cross-section TEM specimen. That is, instead of ion-irradiating the film or foil specimen normal to the major surfaces and observing in plan view (i.e., in the same direction), the specimen is irradiated edge-on (i.e., parallel to the major surfaces) and is observed normal to the depth direction with respect to the irradiation. The results of amorphization of Si, irradiated in this orientation by 1 or 1.5 MeV Kr, are presented and briefly compared with the usual plan view observations. The limitations of the technique are discussed and several experiments which might profitably employ this technique are suggested.

In situ Transmission Electron Microscope observations of mesotaxial silicide formation in the CoSi2/Si system

1989 ◽  
Vol 47 ◽  
pp. 452-453
Author(s):  
R. Hull ◽  
A.E. White ◽  
K.T. Short ◽  
S.M. Yalisove ◽  
D. Loretto
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Ex Situ ◽  
Metal Silicide ◽  
Silicide Formation ◽  
Plan View ◽  
Silicide Layer ◽  
Transmission Electron ◽  
In Situ Experiments

A new technique for synthesis of buried epitaxial metal silicide layers in Si (“mesotaxy”) by high-dose implantation of Co and Ni into Si surfaces has been developed. Subsequent to implantation at energies in the few hundred keV range and doses in the 1017Cm−2 regime, thermal annealing at temperatures up to 1000°C results in the formation of well-defined and relatively high quality Si/metal disilicide/Si structures.The exact implantation and processing conditions are crucial in determining the structure and quality of the buried silicide layer. In this work, we describe transmission electron microscope experiments which illuminate the silicide formation process both by static studies of as-implanted and annealed structures, and dynamical in-situ experiments where as-implanted structures are annealed inside the microscope to mimic the ex-situ annealing conditions. The structure geometry in these materials turns out to be close to ideal for such in-situ experimentation: typical implantation conditions for formation of a contiguous silicide layer result in tlqe metal layers being of the order a few hundred to a thousand Å and buried about 600-1000 Å below the Si surface. In-situ annealing in the plan-view geometry inhibits surface diffusion across the interfaces, which would be expected in the cross-sectional geometry (5). The typical penetration depths attainable in Si with 200 keV electrons, say ~ 1 micron, allow a significant thickness, hsubthin of Si substrate below the metal layer, thickness hm, to be retained during the in-situ experiment such that hm ≪hsubthin. This is important, as it ensures that the film stress condition (which arises because of the difference in bulk lattice parameters between the Si and metal silicide layers) is reasonably representative of the stress conditions relevant for the case of annealing on the unthinned substrate.

An environmental cell Transmission Electron Microscope

1990 ◽  
Vol 48 (4) ◽  
pp. 552-553
Author(s):  
D.K. Dewald ◽  
T.C. Lee ◽  
J.A. Eades ◽  
I.M. Robertson ◽  
H.K. Bimbaum
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Objective Lens ◽  
Pole Piece ◽  
Noticeable Effect ◽  
Plan View ◽  
Handling System ◽  
Transmission Electron ◽  
Environmental Cell ◽  
Cell Transmission

The ability to observe directly and at high spatial resolution the interactions between environments and materials affords the material scientist new and unique opportunities. This capability is realized in the Environmental Cell Transmission Electron Microscope Facility which has been installed as part of the Center for Microanalysis of Materials at the Materials Research Laboratory of the University of Illinois at Urbana-Champaign.The Facility is based on a JEOL 4000EX equipped with a specially designed pole piece. An aperture limited, differentially pumped, environmental cell has been installed in this pole piece. The system is shown schematically in Figures 1 and 2. Figure 1 is a plan view of a section through the objective lens pole-piece, with the microscope axis perpendicular to the plane of the paper, showing the cell enclosing the sample rod, the gas handling system and the location of the magnetically levitated Turbo-Molecular pumps. Figure 2 shows a cross-sectional view of the environmental cell and the gas handling system. As shown in Figure 2 the electron beam passes through a series of five apertures which allow the column vacuum to be maintained while the cell pressure is increased. The actual cell apertures are located at the apex of cones to minimize the gas path length, allow maximum tilt and still permit high- angle diffraction data to be obtained. Differential pumping of the cell is achieved by the four turbo- molecular pumps, the location of which can be seen in the Figures. With this arrangement the environmental cell is capable of supporting 400 torr of N2 gas which has no noticeable effect on the microscope operation. This allows the microscope to be operated with a LaB6 filament. The gas handling system was designed to handle a variety of environments including corrosive ones.

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