Dynamic Scanning Electron Microscopy of Compressed Sand Grains Showing Strain Related Charging Patterns

1974 ◽  
Vol 32 ◽  
pp. 564-565
Author(s):  
W.C. Nixon
Keyword(s):  
Ball Bearing ◽  
Beam Current ◽  
Lanthanum Hexaboride ◽  
Low Noise ◽  
Electron Gun ◽  
Video Tape ◽  
Mechanical Motion ◽  
Voltage Contrast ◽  
Scanning Electron

A special form of two lens scanning electron microscope has been optimised for scanning at television rates and used with a video tape recorder to observe a wide variety of dynamic specimen changes. The electron gun uses either thermionic tungsten or lanthanum hexaboride emitters giving low noise TV images with a beam current of 100 nA in an electron probe that can be as small as 300 A. Special stages may be used for dynamic microcircuit voltage contrast, mechanical motion such as ball bearing rotation, material testing in tension, compression and shear, and certain biological specimens such as human skin viewed directly in situ.

Dynamic Scanning Electron Microscopy of Small Particles

1975 ◽  
Vol 33 ◽  
pp. 280-281
Author(s):  
W. Krakow ◽  
W. C. Nixon
Keyword(s):  
Electron Microscopy ◽  
Low Noise ◽  
Time Sequence ◽  
Field Of View ◽  
Video Tape ◽  
Small Particles ◽  
Polystyrene Spheres ◽  
Field Distributions ◽  
Dynamic Scanning ◽  
Scanning Electron

The scanning electron microscope (SEM) can be run at television scanning rates and used with a video tape recorder to observe dynamic specimen changes. With a conventional tungsten source, a low noise TV image is obtained with a field of view sufficient to cover the area of the specimen to be recorded. Contrast and resolution considerations have been elucidated and many changing specimens have been studied at TV rates.To extend the work on measuring the magnitude of charge and field distributions of small particles in the SEM, we have investigated their motion and electrostatic interaction at TV rates. Fig. 1 shows a time sequence of polystyrene spheres on a conducting grating surface inclined to the microscope axis. In (la) there are four particles present in the field of view, while in (lb) a fifth particle has moved into view.

In Situ SEM Observations of Sintering of Gold Compacts

1976 ◽  
Vol 34 ◽  
pp. 440-441
Author(s):  
E. R. Levin ◽  
G. R. Auth ◽  
K. R. Bube
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Video Tape ◽  
High Magnification ◽  
Ceramic Substrates ◽  
Direct Observations ◽  
Ceramic Surfaces ◽  
Scanning Electron ◽  
Made In

As part of a study of metallization of preglazed ceramic surfaces for hybrid microcircuits, direct observations of the sintering of gold powders at temperatures in the 800-900°C range have been made in the scanning electron microscope. The changes occurring in the layers at the high temperatures were followed in detail at high magnification. Video tape recordings were made showing the sintering of the gold and the accompanying flow of the glass bonding medium.The specimens were specially prepared for the SEM studies on thin rectangular ceramic substrates 0.13mmx2mmx8mm. The unsintered gold powder, dispersed in an organic vehicle, was screen-printed in 1 mm-wide stripes along the length of substrate. Prior to sintering, the organic binder was removed by prefiring in air, typically at 400 °C for two minutes (Fig. 1). An intermediate layer of lead-borosilicate glass was used between the substrate and the metal compact to promote adhesion on sintering.

High Resolution Scanning Electron Microscope Using Lathanum Hexaboride Cathode Electron Gun

1968 ◽  
Vol 26 ◽  
pp. 372-373
Author(s):  
A. N. Broers
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Spherical Aberration ◽  
Lanthanum Hexaboride ◽  
Electron Gun ◽  
Maximum Brightness ◽  
Working Distance ◽  
Scanning Electron ◽  
Better Than

A new scanning electron microscope has been built which uses a lanthanum hexaboride cathode electron gun. The microscope has three magnetic lenses which are prealigned in the electron optical column to better than 20 micron. The final lens has a design spherical aberration of 1.8 cm for a 6 mm working distance. The pole-pieces of the final lens have been machined round within 0.25 micron and are aligned with respect to the axis of the lens to better than 10 micron. The electron gun which has been described previously uses a lanthanum hexaboride rod cathode. The cathode has approximately two orders of magnitude longer life than a 5 mil tungsten hairpin and is capable of producing an electron beam with a maximum brightness of 5.6 x 105 A/cm2 /ster at 12 KV. This brightness is approximately five times greater than that produced by a 5 mil tungsten hairpin under similar conditions.

An Electron Gun Scanning Microscope

1968 ◽  
Vol 26 ◽  
pp. 360-361
Author(s):  
A. V. Crewe ◽  
D. Johnson ◽  
M. Isaacson
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Beam Current ◽  
Angular Spread ◽  
Electron Gun ◽  
Emission Current ◽  
Scanning Microscope ◽  
Schematic Drawing ◽  
Scanning Electron

A simple scanning electron microscope has been built using a field emission electron gun. The gun is used alone, without the aid of auxiliary lenses, and is theoretically capable of producing a 100 Å probe with a beam current of 10-10 A. Such a beam current allows scan times of the order of a few seconds.A schematic drawing of the microscope is shown in Fig. 2. The field emission voltage is applied to the first anode which controls the emission current. An accelerating voltage is applied to the second anode, and the field between the anodes focuses the electrons to form an image of the tip at the specimen. The angular spread of the beam is limited by an aperture on the second anode.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

A computer-control program for TEM in situ fatigue experiments

1989 ◽  
Vol 47 ◽  
pp. 620-621
Author(s):  
Kenneth S. Vecchio ◽  
John A. Hunt
Keyword(s):  
Slow Crack Growth ◽  
Computer Control ◽  
Control Program ◽  
Video Tape ◽  
Computer Control System ◽  
Transmission Electron ◽  
In Situ Experiments ◽  
Tremendous Amount ◽  
And Control

In-situ experiments conducted within a transmission electron microscope provide the operator a unique opportunity to directly observe microstructural phenomena, such as phase transformations and dislocation-precipitate interactions, “as they happen”. However, in-situ experiments usually require a tremendous amount of experimental preparation beforehand, as well as, during the actual experiment. In most cases the researcher must operate and control several pieces of equipment simultaneously. For example, in in-situ deformation experiments, the researcher may have to not only operate the TEM, but also control the straining holder and possibly some recording system such as a video tape machine. When it comes to in-situ fatigue deformation, the experiments became even more complicated with having to control numerous loading cycles while following the slow crack growth. In this paper we will describe a new method for conducting in-situ fatigue experiments using a camputer-controlled tensile straining holder.The tensile straining holder used with computer-control system was manufactured by Philips for the Philips 300 series microscopes. It was necessary to modify the specimen stage area of this holder to work in the Philips 400 series microscopes because the distance between the optic axis and holder airlock is different than in the Philips 300 series microscopes. However, the program and interfacing can easily be modified to work with any goniometer type straining holder which uses a penrmanent magnet motor.

Charging microscopy and cathodoluminescence imaging of semi-insulating gallium arsenide

1986 ◽  
Vol 44 ◽  
pp. 816-817
Author(s):  
T.C. Sheu ◽  
S. Myhajlenko ◽  
D. Davito ◽  
J.L. Edwards ◽  
R. Roedel ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Secondary Electron ◽  
Crystal Defects ◽  
Device Performance ◽  
Gaas Wafer ◽  
Surface Charging ◽  
Gaas Substrates ◽  
Voltage Contrast ◽  
Cathodoluminescence Imaging ◽  
Scanning Electron

Liquid encapsulated Czochralski (LEC) semi-insulating (SI) GaAs has applications in integrated optics and integrated circuits. Yield and device performance is dependent on the homogeniety of the wafers. Therefore, it is important to characterise the uniformity of the GaAs substrates. In this respect, cathodoluminescence (CL) has been used to detect the presence of crystal defects and growth striations. However, when SI GaAs is examined in a scanning electron microscope (SEM), there will be a tendency for the surface to charge up. The surface charging affects the backscattered and secondary electron (SE) yield. Local variations in the surface charge will give rise to contrast (effectively voltage contrast) in the SE image. This may be associated with non-uniformities in the spatial distribution of resistivity. Wakefield et al have made use of “charging microscopy” to reveal resistivity variations across a SI GaAs wafer. In this work we report on CL imaging, the conditions used to obtain “charged” SE images and some aspects of the contrast behaviour.

Imaging of polymer single crystals in low-voltage, high-resolution scanning electron microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 1106-1107
Author(s):  
W.W. Adams ◽  
G. Price ◽  
A. Krause
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Single Crystals ◽  
Low Voltage ◽  
Polymer Surface ◽  
Beam Current ◽  
Image Features ◽  
First Results ◽  
Scanning Electron

It has been shown that there are numerous advantages in imaging both coated and uncoated polymers in scanning electron microscopy (SEM) at low voltages (LV) from 0.5 to 2.0 keV compared to imaging at conventional voltages of 10 to 20 keV. The disadvantages of LVSEM of degraded resolution and decreased beam current have been overcome with the new generation of field emission gun SEMs. In imaging metal coated polymers in LVSEM beam damage is reduced, contrast is improved, and charging from irregularly shaped features (which may be unevenly coated) is reduced or eliminated. Imaging uncoated polymers in LVSEM allows direct observation of the surface with little or no charging and with no alterations of surface features from the metal coating process required for higher voltage imaging. This is particularly important for high resolution (HR) studies of polymers where it is desired to image features 1 to 10 nm in size. Metal sputter coating techniques produce a 10 - 20 nm film that has its own texture which can obscure topographical features of the original polymer surface. In examining thin, uncoated insulating samples on a conducting substrate at low voltages the effect of sample-beam interactions on image formation and resolution will differ significantly from the effect at higher accelerating voltages. We discuss here sample-beam interactions in single crystals on conducting substrates at low voltages and also present the first results on HRSEM of single crystal morphologies which show some of these effects.

High-Resolution Resistance Mapping in SEM

2018 ◽  
Author(s):  
Grigore Moldovan ◽  
Wolfgang Joachimi ◽  
Guillaume Boetsch ◽  
Jörg Jatzkowski ◽  
Frank Altman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Reference Structure ◽  
Total Resistance ◽  
Embedded Electronics ◽  
Improved Performance ◽  
Mapping Techniques ◽  
Scanning Electron

Abstract This work presents advanced resistance mapping techniques based on Scanning Electron Microscopy (SEM) with nanoprobing systems and the related embedded electronics. Focus is placed on recent advances to reduce noise and increase speed, such as integration of dedicated in situ electronics into the nanoprobing platform, as well as an important transition from current-sensitive to voltagesensitive amplification. We show that it is now possible to record resistance maps with a resistance sensitivity in the 10W range, even when the total resistance of the mapped structures is in the range of 100W. A reference structure is used to illustrate the improved performance, and a lowresistance failure case is presented as an example of analysis made possible by these developments.

Solving the Voltage Contrast on Floating Substrate with Standard FA Toolset

2016 ◽  
Author(s):  
Julien Goxe ◽  
Béatrice Vanhuffel ◽  
Marie Castignolles ◽  
Thomas Zirilli
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Sample Preparation ◽  
Failure Analysis ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Silicon On Insulator ◽  
Mixed Signal ◽  
Voltage Contrast ◽  
Scanning Electron

Abstract Passive Voltage Contrast (PVC) in a Scanning Electron Microscope (SEM) or a Focused Ion Beam (FIB) is a key Failure Analysis (FA) technique to highlight a leaky gate. The introduction of Silicon On Insulator (SOI) substrate in our recent automotive analog mixed-signal technology highlighted a new challenge: the Bottom Oxide (BOX) layer, by isolating the Silicon Active Area from the bulk made PVC technique less effective in finding leaky MOSFET gates. A solution involving sample preparation performed with standard FA toolset is proposed to enhance PVC on SOI substrate.

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