scholarly journals Electron Gun Technologies for High Resolution Electron Microscopes

2012 ◽  
Vol 55 (2) ◽  
pp. 64-72 ◽  
Author(s):  
Shin FUJITA
Keyword(s):  
High Resolution ◽  
Electron Gun ◽  
Resolution Electron ◽  
Electron Microscopes

Atomic structure imaging of the Si/SiO2 interface with high-resolution electron microscopy

1986 ◽  
Vol 44 ◽  
pp. 390-391
Author(s):  
J.L. Batstone ◽  
J.M. Gibson ◽  
Alice.E. White ◽  
K.T. Short
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Atomic Structure ◽  
High Resolution Electron Microscopy ◽  
Medium Voltage ◽  
Voltage Electron ◽  
Resolution Electron ◽  
Structural Image ◽  
Electron Microscopes ◽  
Point To Point

High resolution electron microscopy (HREM) is a powerful tool for the determination of interface atomic structure. With the previous generation of HREM's of point-to-point resolution (rpp) >2.5Å, imaging of semiconductors in only <110> directions was possible. Useful imaging of other important zone axes became available with the advent of high voltage, high resolution microscopes with rpp <1.8Å, leading to a study of the NiSi2 interface. More recently, it was shown that images in <100>, <111> and <112> directions are easily obtainable from Si in the new medium voltage electron microscopes. We report here the examination of the important Si/Si02 interface with the use of a JEOL 4000EX HREM with rpp <1.8Å, in a <100> orientation. This represents a true structural image of this interface.

The Contribution of Intermediate-Voltage, High-Resolution Electron Microscopy In Materials Science: An Appraisal

1990 ◽  
Vol 48 (1) ◽  
pp. 478-479
Author(s):  
John L. Hutchison
Keyword(s):  
High Resolution ◽  
Materials Science ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
The Past ◽  
Resolution Electron ◽  
Extreme Sensitivity ◽  
Electron Microscopes ◽  
New Generation ◽  
Small Metal Particles

Over the past five years or so the development of a new generation of high resolution electron microscopes operating routinely in the 300-400 kilovolt range has produced a dramatic increase in resolution, to around 1.6 Å for “structure resolution” and approaching 1.2 Å for information limits. With a large number of such instruments now in operation it is timely to assess their impact in the various areas of materials science where they are now being used. Are they falling short of the early expectations? Generally, the manufacturers’ claims regarding resolution are being met, but one unexpected factor which has emerged is the extreme sensitivity of these instruments to both floor-borne and acoustic vibrations. Successful measures to counteract these disturbances may require the use of special anti-vibration blocks, or even simple oil-filled dampers together with springs, with heavy curtaining around the microscope room to reduce noise levels. In assessing performance levels, optical diffraction analysis is becoming the accepted method, with rotational averaging useful for obtaining a good measure of information limits. It is worth noting here that microscope alignment becomes very critical for the highest resolution.In attempting an appraisal of the contributions of intermediate voltage HREMs to materials science we will outline a few of the areas where they are most widely used. These include semiconductors, oxides, and small metal particles, in addition to metals and minerals.

A New ion Beam Based Etching/Coating System for Scanning Electron Microscopy (SEM) and Light Microscopy (LM)

1997 ◽  
Vol 3 (S2) ◽  
pp. 363-364
Author(s):  
R. Alani ◽  
R.J. Mitro ◽  
C.M. Tabatt ◽  
L. Malaszewski
Keyword(s):  
High Resolution ◽  
Ion Beam ◽  
Coating System ◽  
Etching Technique ◽  
Specimen Handling ◽  
Conductive Films ◽  
Resolution Electron ◽  
New Instrument ◽  
Electron Microscopes ◽  
And Performance

The design and performance of a new instrument, based on improved Penning ion guns [1] for etching and coating samples for SEM and LM in a single vacuum chamber, are described. The instrument is based on an existing high resolution ion beam coating system, which is capable of producing high quality ultra-thin and amorphous conductive films, required for present high resolution electron microscopes. [2]. The fact that in this system both etching and coating processes are combined in one chamber, the specimen handling and specimen contamination are minimized. Furthermore, the system eliminates the traditional multiple mounting /dismounting of samples to various holders for mechanical polishing, etching, coating and microscopy purposes. The specimen can stay with the same holder throughout the entire process, increasing the sample through-put. Moreover, the system offers an alternative method to the traditional “wet chemical etching,” technique with its well known problems.

Improved High Resolution Electron Gun for Television Cameras

1963 ◽  
Vol 72 (10) ◽  
pp. 792-794
Author(s):  
S. Gray ◽  
P. C. Murray ◽  
O. J. Ziemelis
Keyword(s):  
High Resolution ◽  
Electron Gun ◽  
Resolution Electron

Characterization of Grain Boundaries and Interfaces by High Resolution Transmission Electron Microscopy

1989 ◽  
Vol 153 ◽  
Author(s):  
William Krakow
Keyword(s):  
High Resolution ◽  
Grain Boundaries ◽  
Ohmic Contacts ◽  
Dielectric Material ◽  
Medium Voltage ◽  
Voltage Electron ◽  
Resolution Electron ◽  
Interfacial Structures ◽  
Tilt Boundaries ◽  
Electron Microscopes

AbstractSeveral examples will be given of high resolution electron microscope images of both grain boundaries and interfaces and the methods which have been applied to understanding their atomic structure. Specific expitaxial interfacial structures considered are: Pd2Si/Si used for ohmic contacts, Al on Si overlayers and CaF2/Si where the CaF2, is an attractive possibility as a dielectric material. For the case of grain boundaries specific examples of both twist and tilt boundaries in Au will be given to show the imaging capability with the new generation of medium voltage electron microscopes.

Interpretation of high-resolution TEM images of substitutional systems with a column structure

1983 ◽  
Vol 41 ◽  
pp. 236-237
Author(s):  
G. Van Tendeloo ◽  
D. Van Dyck ◽  
S. Amelinckx
Keyword(s):  
High Resolution ◽  
Structural Features ◽  
Crystal Thickness ◽  
Contrast Transfer Function ◽  
Resolution Electron ◽  
High Resolution Tem ◽  
Direct Interpretation ◽  
High Resolution Electron Microscope ◽  
Electron Microscopes ◽  
Almost All

Direct interpretation of high resolution electron microscope images in terms of the projected potential or projected charge density is only possible for very thin specimens and at a properly chosen defocus value. In most of the substitutional alloy systems such as those based on the fee basic lattice in which electron diffraction is strongly dynamical the useful crystal thickness is limited to the order of 1 nm which is rearly met in practice. Furthermore for almost all of the available electron microscopes the Scherzer plateau of the contrast transfer function is not large enough to contain even the first Bragg beams that carry information about the fee lattice. Nevertheless it has been shown in a number of papers on ordering in fcc-based Au-Mn alloys as well as in other heavy metal fee based alloys that under suitable conditions the images represent the structural features of these alloys in a directly interpretable manner. In particular the configuration of the minority atom columns can be imaged as bright dots. We shall indicate here semi-analytically why and under which conditions this conclusion is justified.

Surface studies in UHV: Applications of High-resolution electron microscopy

1991 ◽  
Vol 49 ◽  
pp. 444-445
Author(s):  
M. R. McCartney ◽  
David J. Smith
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Vacuum ◽  
High Resolution Electron Microscopy ◽  
Plan View ◽  
Voltage Electron ◽  
Resolution Electron ◽  
Video Systems ◽  
Electron Microscopes

The examination of surfaces requires not only that they be free of adsorbed layers but the environment of the sample must also be maintained at high vacuum so that the surfaces remain clean. The possibility of resolving surface structures with atomic resolution has provided the motivation for optimizing intermediate and high voltage electron microscopes for this particular application. Electron microscopy offers a variety of techniques which have the capability of achieving atomic level detail of surfaces including plan-view imaging, REM and profile imaging. Operation at higher voltages permits reasonable pole piece dimensions thereby providing space for in situ studies yet still compatible with high resolution. Moreover, video systems can be attached which permit observation and recording of dynamic phenomena without compromising microscope performance.

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