Interfacial Structures in the Nb/MgO/Nb/Al2O3 Superlattice

1991 ◽  
Vol 49 ◽  
pp. 960-961
Author(s):  
D. X. Li ◽  
P. Pirouz ◽  
A. H. Heuer ◽  
S. Yadavalli ◽  
C. P. Flynn
Keyword(s):  
Ion Beam ◽  
Mechanical Grinding ◽  
Cross Sectional ◽  
Mbe Growth ◽  
Resolution Electron ◽  
Interfacial Structures ◽  
High Resolution Electron Microscope ◽  
Point To Point ◽  
Image Simulations ◽  
Standard Techniques

Nb/MgO/Nb/Al2O3 superlattices were prepared by MBE growth of Nb and MgO films on a (012)Al2O3 sapphire substrate. Cross sectional HREM specimens were prepared using standard techniques involving mechanical grinding to a thickness of 0.13 mm, dimpling to a thickness of 20 μm and ion beam milling at 6 kV. The samples were subsequently examined in a top-entry JEOL 4000EX high resolution electron microscope with a point-to-point resolution of ∼0.19 nm. Image simulations were performed using the SHRLI programs developed by O'Keefe.

Interfacial structure and interfacial reactions at the MgO/Al2O3 interface

1991 ◽  
Vol 49 ◽  
pp. 696-697
Author(s):  
D. X. Li ◽  
P. Pirouz ◽  
A. H. Heuer ◽  
S. Yadavalli ◽  
C. P. Flynn
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Molecular Beam ◽  
Interfacial Structure ◽  
Cross Sectional ◽  
Resolution Electron ◽  
High Resolution Electron Microscope ◽  
Electron Microscope Image ◽  
Image Simulations ◽  
Standard Techniques

MgO films were deposited on the (sample A), (0001)Al2O3 (sample B), and the (sample C) planes of sapphire by Molecular Beam Epitaxy (MBE). Cross-sectional UREM specimens were prepared using standard techniques and examined in a top-entry JEOL 4000FX high resolution electron microscope. Image simulations were performed using the SHRLI programs developed by O'Keefe.

Formation process of silicide at Pt-Si (111) interface

1988 ◽  
Vol 46 ◽  
pp. 484-485
Author(s):  
Y. yokota ◽  
H. Hashimoto
Keyword(s):  
Electron Microscope ◽  
Formation Process ◽  
Ion Beam ◽  
Cross Sectional ◽  
Platinum Silicide ◽  
Initial Stage ◽  
Resolution Electron ◽  
High Resolution Electron Microscope ◽  
Diamond Saw ◽  
Si Wafer

The initial stage of the reaction process forming the platinum silicide at Pt/Si (111) interfaces have been investigated by a high resolution electron microscope in both “flat-on” [1] and “cross-sectional” mode.First, platinum of 11 nm thickness was deposited on a Si (111) wafer. For observing the specimen in “flat-on” mode, the top surface and edge of the specimen were covered by paraffin and etched chemically using CP-4 reagent from backside. The specimen for observing in “cross-sectional” mode was prepared as follows. The Si wafer was cut into slips of 3mm width. After stacking 4 to 6 slips together with epoxy resin, the stacks were sliced to a thickness of 0.3-0.4mm by a diamond saw. The slices were mechanically polished to a thickness lower than 0.05mm and then thinned by Ar ion beam.The formation process of platinum silicide (PtSi) was observed in a cross-sectional specimen.

HREM of epitaxially grown Fe/TiO2 and Cu/TiO2 interfaces

1993 ◽  
Vol 51 ◽  
pp. 834-835
Author(s):  
P. Lu ◽  
F. Cosandey
Keyword(s):  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Select Area Diffraction ◽  
Ion Milling ◽  
Cross Sectional ◽  
Oxide Interfaces ◽  
Atomic Structures ◽  
Resolution Electron ◽  
High Resolution Electron Microscope ◽  
Standard Techniques

High-resolution electron microscopy (HREM) has been used to provide information on atomic structures of metal/oxide interfaces, which are of both scientific and technological interest. In this report, we present results of a study on Fe/TiO2 and Cu/TiO2 interfaces by HREM. The Fe/TiO2 and Cu/TiO2 interfaces were formed by vapor deposition of Fe and Cu on TiO2 (110) surface, respectively, in a UHV chamber with a base pressure of ∽1x10−10 torr. Cross sectional HREM specimens were prepared using standard techniques involving mechanical polishing, dimpling and ion-milling. The samples were examined in an Topcon-002B high-resolution electron microscope. HREM simulations were performed using the EMS program.Figs, 1a and 1b show a HREM micrograph and a select area diffraction pattern of Fe/TiO2 interface, respectively, taken along the TiO2 [001] direction. From Fig.la and Fig.1b, the following orientation relationship is obtained: [001]Fe//[001]TiO2 and (100)Fe//(110)TiO2. With this orientation, there is about 12.6% lattice misfitt along the TiO2 [10] direction.

Characterization of Rh/Si multilayer structure by HREM and HAADF

1992 ◽  
Vol 50 (1) ◽  
pp. 122-123
Author(s):  
Y. Cheng ◽  
J. Liu ◽  
M.B. Stearns ◽  
D.G. Steams
Keyword(s):  
Normal Incidence ◽  
High Resolution Electron Microscopy ◽  
X Rays ◽  
Beam Direction ◽  
Cross Sectional ◽  
Optical Elements ◽  
Resolution Electron ◽  
Point To Point ◽  
Better Than

The Rh/Si multilayer (ML) thin films are promising optical elements for soft x-rays since they have a calculated normal incidence reflectivity of ∼60% at a x-ray wavelength of ∼13 nm. However, a reflectivity of only 28% has been attained to date for ML fabricated by dc magnetron sputtering. In order to determine the cause of this degraded reflectivity the microstructure of this ML was examined on cross-sectional specimens with two high-resolution electron microscopy (HREM and HAADF) techniques.Cross-sectional specimens were made from an as-prepared ML sample and from the same ML annealed at 298 °C for 1 and 100 hours. The specimens were imaged using a JEM-4000EX TEM operating at 400 kV with a point-to-point resolution of better than 0.17 nm. The specimens were viewed along Si [110] projection of the substrate, with the (001) Si surface plane parallel to the beam direction.

Observation of the CdTe-GaAs Interface by High Resolution Electron Microscopy

1984 ◽  
Vol 37 ◽  
Author(s):  
N. Otsuka ◽  
L. A. Kolodziejski ◽  
R. L. Gunshor ◽  
S. Datta ◽  
R. N. Bicknell ◽  
...  
Keyword(s):  
High Resolution ◽  
Film Growth ◽  
Substrate Surface ◽  
High Resolution Electron Microscopy ◽  
Gaas Substrates ◽  
Resolution Electron ◽  
Interfacial Structures ◽  
Substrate Preheating ◽  
High Resolution Electron Microscope

AbstractCdTe films have been grown on GaAs substrates with two types of interfaces - one with the epitaxial relation (111)CdTe║ (100)GaAs and the other with (100)CdTe║ (100)GaAs,. High resolution electron microscope observation of the two types of interfaces was carried out in order to determine the role of the substrate surface microstructure in determining the epitaxy. The interface of the former type shows a direct contact between the CdTe and GaAs crystals, while the interface of the latter type has a very thin oxide layer (∼10 Å in thickness) between the two crystals. These observations suggest that details of the substrate preheating cycle prior to film growth is the principle factor in determining which epitaxial relation occurs in this system. The relation between interfacial structures and the origin of the two epitaxial relations is discussed.

Dynamic TEM Observation on Oxide Glass Materials

1990 ◽  
Vol 183 ◽  
Author(s):  
Sumio Iijima
Keyword(s):  
Electron Beam Irradiation ◽  
Amorphous Film ◽  
Oxide Glass ◽  
Model Structure ◽  
Resolution Electron ◽  
Atom Migration ◽  
Intense Electron Beam ◽  
High Resolution Electron Microscope ◽  
Intense Electron ◽  
Image Simulations

AbstractIntensity fluctuation in high resolution electron microscope (HREM) images of amorphous Tl-Ba-Ca-Cu-O oxide films is observed. The fluctuation with a frequency of few tens of Hertz and an amplitude of about 0.3nm, occurs under an intense electron beam irradiation. It is shown experimentally that atom migration in the films is responsible for the fluctuations. The result is also supported by computer image simulations on a model structure for amorphous film.

Atomic structure of CdTe dislocations studied by HREM

1989 ◽  
Vol 47 ◽  
pp. 576-577
Author(s):  
P. Lu ◽  
R.W. Glaisher ◽  
David J. Smith
Keyword(s):  
Electron Microscopy ◽  
Ion Beam ◽  
High Resolution Electron Microscopy ◽  
Resolution Limit ◽  
The Core ◽  
Partial Dislocations ◽  
Resolution Electron ◽  
Argon Ion ◽  
Image Simulations

The determination of the atomic core of dislocations in semiconductors is a challenging problem for high-resolution electron microscopy(HREM). In previous studies, various defects in elemental semiconductors, III-V and II-VI compound semiconductors have been reported. In particular, the core structure of the 30° partial dislocations in silicon, which are dissociated from a perfect 60° dislocation, have been deduced. present study, various CdTe dislocations have been imaged at 400keV. and their core structures have been analyzed with assistance from multi-slice image simulations. Sections of CdTe single crystal were cut normal to the [110] direction, followed by mechanically polishing to a thickness of ˜ 20 microns and finally argon ion-beam milling to perforation for electron microscopy. The crystals were examined with a JEM-4000EX. having a structure resolution limit of ˜ 1.7Å at 400keV.

The Direct Observation of Atomic Surface Structure and Inclined Planar Defects in Au(111) Films

1981 ◽  
Vol 10 ◽  
Author(s):  
William Krakow
Keyword(s):  
Single Atom ◽  
Bottom Surface ◽  
Stacking Sequence ◽  
Planar Defects ◽  
Resolution Electron ◽  
Atomic Surface ◽  
High Resolution Electron Microscope ◽  
Diffraction Effects ◽  
First Time ◽  
Image Simulations

With a high resolution electron microscope it is possible to image directly the atomic surface lattice of vapor-deposited Au(111) films. The contrast of the surface atoms can be either black or white relative to the background which is characteristic of close-packed planes of atoms in the stacking sequence ABCABC.... An analysis of these images was performed using multislice dynamical diffraction computations of 256 × 256 = 65 536 reciprocal space points and subsequent image simulations. The effects of top and bottom surface roughness, different termination layers and the contrast compared with single-atom imaging are considered.The identification of atomic structure detail at incoherent double-position boundaries in these (111) films was also achieved. Surface layer terminations, variations in the choice of every third matching plane and the possibility that twinning planes produce boundaries with jogs were investigated. Multislice computer programs were designed to calculate the diffraction effects from these inclined boundaries using two-dimensional fast Fourier transform and shift techniques of the projected potential. This is the first time that inclined planar defects have been analyzed in this manner.

A Selective Growth of GaAs Microcrystals Grown on Se-Terminated GaAlAs Surface for the Quantum well Box Structure

1992 ◽  
Vol 283 ◽  
Author(s):  
Toyohiro Chikyow ◽  
Nobuyuki Koguchi
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Quantum Well ◽  
Epitaxial Growth ◽  
Selective Growth ◽  
Layer Formation ◽  
Cross Sectional ◽  
Resolution Electron ◽  
Box Structure ◽  
High Resolution Electron Microscope

ABSTRACTA selective growth of GaAs microcrystals was demonstrated on a Se-terminated GaAlAs surface. Ga molecules were supplied to the Se-terminated GaAlAs surface at first. The surface consisted of Ga droplets and bared Se-terminated GaAlAs surface. After the following As molecule supply to the surface, a selective GaAs microcrystal growth from Ga droplets was observed. The cross sectional investigations by the high resolution electron microscope revealed epitaxial growth of GaAs microcrystals with (111) facets and a possibility of (GaAl)2Se3, layer formation at the GaAs/Se-terminated GaAlAs interface.

Interpretation of the Atomic Surface Structure of Ag2O on (111) Au thin films

1983 ◽  
Vol 31 ◽  
Author(s):  
William Krakow
Keyword(s):  
Surface Structure ◽  
Image Features ◽  
Electron Microscope Investigation ◽  
Resolution Electron ◽  
Atomic Surface ◽  
High Resolution Electron Microscope ◽  
Au Thin Films ◽  
Diffraction Patterns ◽  
Digital Frame ◽  
Image Simulations

ABSTRACTA high resolution electron microscope investigation of the residual oxidized silver of a few monolayers thickness on the surface of (111) Au films has shown that a reconstructed (2×1) surface structure occurs for (110) oriented Ag2O and can be observed at atomic resolution levels. Image enhancement via a digital frame store processor has revealed improved images which have then been compared to computer simulated diffraction patterns and images of the Ag2O surface. Several iterations of surface structure models and image simulations reveal that the (2×1) reconstruction is consistent with a missing row model. The atomic arrangements of these rows often undergo a translation along the direction of the row to produce cusp like image features. It has also been possible to observe the effect of contraction of the underlying layer which can produce diagonal contrast lines in the images. These features often vary rapidly over lateral distances of a few tens of angstroms and give an indication of the surface topography and the degree ordering of the surface.

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