Inelastic Scattering Components in the Si(111)-(7×7) RHEED Pattern by the Energy Filtering Method

1998 ◽  
Vol 05 (03n04) ◽  
pp. 755-760
Author(s):  
Y. Horio ◽  
Y. Urakami ◽  
Y. Hashimoto
Keyword(s):  
Electron Beam ◽  
Energy Loss ◽  
Surface Plasmon ◽  
Rheed Pattern ◽  
Kikuchi Line ◽  
Energy Filtering ◽  
Distinct Structure ◽  
Bulk Plasmon ◽  
Glancing Angle ◽  
Takeoff Angle

Energy loss spectra for several parts of the Si(111)-(7 × 7) RHEED pattern, the (0 0) specular spot, the (3/7 3/7) superspot in the zeroth Laue zone, the (0 1) fundamental spot in the first Laue zone, and the Kikuchi line and background have been measured by the recently developed retarding type energy filter in the condition of the [Formula: see text] azimuth with a 10 kV incident electron beam. It was found that there are some differences in their spectra. Energy loss spectra of the (0 0) and (3/7 3/7) spots show surface plasmon loss peaks of silicon dominantly, and the spectrum of the (0 1) spot shows the same but includes weak bulk plasmon peaks. The spectrum of the Kikuchi line mainly shows bulk plasmon peaks and that of the background has no distinct structure in the profile. Glancing angle dependences of their profiles were also measured and discussed. The experimental data show that there is a relation between the quasielastic component of the diffraction beam and the pass length of the electron beam in a vacuum region near the surface where the electron interacts with the surface plasmon. The quasielastic component of the diffraction beam decreases as the incident glancing angle and/or takeoff angle become grazing.

THERMO-INDUCED SHIFT OF PLASMON ENERGY IN ELECTRON LOSS SPECTRA FOR THE ORDERING Pt80Co20(111) ALLOY SURFACE

2009 ◽  
Vol 16 (02) ◽  
pp. 249-258 ◽  
Author(s):  
V. A. TINKOV ◽  
M. A. VASYLYEV
Keyword(s):  
Energy Loss ◽  
Surface Plasmon ◽  
Energy Shift ◽  
Primary Electron ◽  
Thin Layers ◽  
Plasmon Energy ◽  
Concentration Depth Profile ◽  
Bulk Plasmon ◽  
Electron Energy Loss ◽  
The Relationship

Electron energy loss spectroscopy has been used for the investigation of the surface and bulk plasmon excitations depending on the heating in the ultra-thin layers of ordering Pt 80 Co 20(111) alloy from the primary electron beam energies E0 ranging from 200 to 650 eV. Thermo-induced shift of plasmon energy and damping of intensity line of the surface plasmon relative to the bulk plasmon were observed. With an increase in alloy heating, the energy of surface and bulk plasmons is shifted with lowering energy in the whole range E0 and the higher the temperature the higher the shifts of plasmon energy. The physical processes that can influence on the energy shift of plasmon oscillations in the energy loss spectra at heating are considered. The relationship between the damping of oscillating concentration depth profile and the surface plasmon damping at heating was established.

Microanalysis with high Spatial Resolution

1983 ◽  
Vol 31 ◽  
Author(s):  
P. E. Batson ◽  
C. R. M. Grovenor ◽  
D. A. Smith ◽  
C. Wong
Keyword(s):  
Electron Beam ◽  
Energy Loss ◽  
Inelastic Scattering ◽  
Electron Energy ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
X Rays ◽  
Elemental Microanalysis ◽  
Bulk Plasmon ◽  
Electron Energy Loss

ABSTRACTElemental microanalysis, using x-rays and electron energy loss scattering, has been shown to be possible with electron beam probe sizes down to 0.5nm. This paper will discuss some practical problems, such as specimen drift, signal magnitude, and probe-specimen interaction when the probe is made very small. These problems have arisen in two studies: 1) an investigation of as segregation in poly-crystalline Si and 2) imaging of metal spheres with surface and bulk plasmon inelastic scattering.

A very rapid in situ Kikuchi technique to determine relative crystal misorientation

1988 ◽  
Vol 46 ◽  
pp. 830-831
Author(s):  
J. I. Bennetch
Keyword(s):  
Electron Beam ◽  
Analytical Techniques ◽  
Superplastic Forming ◽  
The Other ◽  
Kikuchi Pattern ◽  
Kikuchi Line ◽  
Line Analysis

In a recent study of the superplastic forming (SPF) behavior of certain Al-Li-X alloys, the relative misorientation between adjacent (sub)grains proved to be an important parameter. It is well established that the most accurate way to determine misorientation across boundaries is by Kikuchi line analysis. However, the SPF study required the characterization of a large number of (sub)grains in each sample to be statistically meaningful, a very time-consuming task even for comparatively rapid Kikuchi analytical techniques.In order to circumvent this problem, an alternate, even more rapid in-situ Kikuchi technique was devised, eliminating the need for the developing of negatives and any subsequent measurements on photographic plates. All that is required is a double tilt low backlash goniometer capable of tilting ± 45° in one axis and ± 30° in the other axis. The procedure is as follows. While viewing the microscope screen, one merely tilts the specimen until a standard recognizable reference Kikuchi pattern is centered, making sure, at the same time, that the focused electron beam remains on the (sub)grain in question.

Probing the Chemistry and Spectroscopy of Radiation-Sensitive Polymers by Parallel-Detection EELS

1990 ◽  
Vol 48 (2) ◽  
pp. 34-35
Author(s):  
E. G. Rightor ◽  
G. P. Young
Keyword(s):  
Electron Beam ◽  
Bisphenol A ◽  
Energy Loss ◽  
Parallel Detection ◽  
Commercial Grade ◽  
Incident Electron Beam ◽  
Ptfe Sample ◽  
Spectroscopic Information ◽  
Edge Features ◽  
Electron Energy Loss

Investigation of neat polymers by TEM is often thwarted by their sensitivity to the incident electron beam, which also limits the usefulness of chemical and spectroscopic information available by electron energy loss spectroscopy (EELS) for these materials. However, parallel-detection EELS systems allow reduced radiation damage, due to their far greater efficiency, thereby promoting their use to obtain this information for polymers. This is evident in qualitative identification of beam sensitive components in polymer blends and detailed investigations of near-edge features of homopolymers.Spectra were obtained for a poly(bisphenol-A carbonate) (BPAC) blend containing poly(tetrafluoroethylene) (PTFE) using a parallel-EELS and a serial-EELS (Gatan 666, 607) for comparison. A series of homopolymers was also examined using parallel-EELS on a JEOL 2000FX TEM employing a LaB6 filament at 100 kV. Pure homopolymers were obtained from Scientific Polymer Products. The PTFE sample was commercial grade. Polymers were microtomed on a Reichert-Jung Ultracut E and placed on holey carbon grids.

The use of an energy-filtering electron microscope to reduce chromatic aberration in images of thick biological specimens

1986 ◽  
Vol 44 ◽  
pp. 88-91
Author(s):  
L. D. Peachey ◽  
J. P. Heath ◽  
G. Lamprecht
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Cross Section ◽  
Electron Scattering ◽  
Chromatic Aberration ◽  
Image Resolution ◽  
Incident Electron Energy ◽  
Energy Filtering ◽  
Transmission Electron

Biological specimens of cells and tissues generally are considerably thicker than ideal for high resolution transmission electron microscopy. Actual image resolution achieved is limited by chromatic aberration in the image forming electron lenses combined with significant energy loss in the electron beam due to inelastic scattering in the specimen. Increased accelerating voltages (HVEM, IVEM) have been used to reduce the adverse effects of chromatic aberration by decreasing the electron scattering cross-section of the elements in the specimen and by increasing the incident electron energy.

Electron beam induced current study of thin silicon layers on insulator substrate

1990 ◽  
Vol 48 (4) ◽  
pp. 618-619
Author(s):  
A. Buczkowski ◽  
Z. J. Radzimski ◽  
J. C. Russ ◽  
G. A. Rozgonyi
Keyword(s):  
Electron Beam ◽  
Energy Loss ◽  
Beam Energy ◽  
Collection Efficiency ◽  
Silicon Layer ◽  
Depletion Layer ◽  
Incident Electron Energy ◽  
Induced Current ◽  
Electron Hole ◽  
Electron Beam Induced Current

If a thickness of a semiconductor is smaller than the penetration depth of the electron beam, e.g. in silicon on insulator (SOI) structures, only a small portion of incident electrons energy , which is lost in a superficial silicon layer separated by the oxide from the substrate, contributes to the electron beam induced current (EBIC). Because the energy loss distribution of primary beam is not uniform and varies with beam energy, it is not straightforward to predict the optimum conditions for using this technique. Moreover, the energy losses in an ohmic or Schottky contact complicate this prediction. None of the existing theories, which are based on an assumption of a point-like region of electron beam generation, can be used satisfactorily on SOI structures. We have used a Monte Carlo technique which provide a simulation of the electron beam interactions with thin multilayer structures. The EBIC current was calculated using a simple one dimensional geometry, i.e. depletion layer separating electron- hole pairs spreads out to infinity in x- and y-direction. A point-type generation function with location being an actual location of an incident electron energy loss event has been assumed. A collection efficiency of electron-hole pairs was assumed to be 100% for carriers generated within the depletion layer, and inversely proportional to the exponential function of depth with the effective diffusion length as a parameter outside this layer. A series of simulations were performed for various thicknesses of superficial silicon layer. The geometries used for simulations were chosen to match the "real" samples used in the experimental part of this work. The theoretical data presented in Fig. 1 show how significandy the gain decreases with a decrease in superficial layer thickness in comparison with bulk material. Moreover, there is an optimum beam energy at which the gain reaches its maximum value for particular silicon thickness.

3d Reconstruction of Sub-Nm Beam Profiles in STEM

2001 ◽  
Vol 7 (S2) ◽  
pp. 344-345
Author(s):  
G. Möbus ◽  
R.E. Dunin-Borkowski ◽  
C.J.D. Hethėrington ◽  
J.L. Hutchison
Keyword(s):  
Electron Beam ◽  
Chemical Analysis ◽  
Energy Loss ◽  
Intensity Distribution ◽  
Dark Field ◽  
Beam Forming ◽  
Dark Field Imaging ◽  
Annular Dark Field ◽  
Electron Energy Loss ◽  
Field Imaging

Introduction:Atomically resolved chemical analysis using techniques such as electron energy loss spectroscopy and annular dark field imaging relies on the ability to form a well-characterised sub-nm electron beam in a FEGTEM/STEM [1-2]. to understand EELS+EDX-signal formation upon propagation of a sub-nm beam through materials we first have to assess precisely the beam intensity distribution in vacuum and find conditions for the best obtainable resolution.Experimental Details:Modern TEM/STEM instruments combine features of both imaging and scanning technology. The beam forming capability approaches closely that for dedicated STEMs, while CCD recording devices allow us to measure the beam profile by direct imaging at magnifications up to 1.5 M. The recording of a “z-section” series through the 3D intensity distribution of the cross-over can therefore be realised by recording of a “condenser focal series”.

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