Development of Aberration-Corrected Electron Microscopy

2008 ◽  
Vol 14 (1) ◽  
pp. 2-15 ◽  
Author(s):  
David J. Smith
Keyword(s):  
Electron Microscopy ◽  
Spherical Aberration ◽  
Materials Characterization ◽  
Electron Holography ◽  
Aberration Correction ◽  
Future Prospects ◽  
Microscopy Image ◽  
Recent Developments ◽  
Fixed Beam ◽  
Aberration Corrected

The successful correction of spherical aberration is an exciting and revolutionary development for the whole field of electron microscopy. Image interpretability can be extended out to sub-Ångstrom levels, thereby creating many novel opportunities for materials characterization. Correction of lens aberrations involves either direct (online) hardware attachments in fixed-beam or scanning TEM or indirect (off-line) software processing using either off-axis electron holography or focal-series reconstruction. This review traces some of the important steps along the path to realizing aberration correction, including early attempts with hardware correctors, the development of online microscope control, and methods for accurate measurement of aberrations. Recent developments and some initial applications of aberration-corrected electron microscopy using these different approaches are surveyed. Finally, future prospects and problems are briefly discussed.

Recent Developments in TEM Applications for the IC Industry

2008 ◽  
Author(s):  
L. F. Fu ◽  
Y. C. Wang ◽  
B. Jiang ◽  
F. Shen ◽  
M. Strauss ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gate Oxide ◽  
Transmission Electron Microscopy Image ◽  
New Developments ◽  
Electron Microscopy Image ◽  
Transmission Electron ◽  
Microscopy Image ◽  
Recent Developments ◽  
Aberration Corrected

Abstract Recent developments in aberration-corrected transmission electron microscopy have drawn much attention from the semiconductor characterization community. Two new developments in transmission electron microscopy, image aberration correctors and probe aberration correctors, are discussed in term of their applications in characterizing gate oxide dielectrics for the IC industry.

scholarly journals Introduction: Materials Research in an Aberration-Free Environment

2008 ◽  
Vol 14 (1) ◽  
pp. 1-1 ◽  
Author(s):  
David J. Smith
Keyword(s):  
Electron Microscopy ◽  
Spherical Aberration ◽  
Image Interpretation ◽  
Special Issue ◽  
Materials Research ◽  
Free Environment ◽  
Beam Currents ◽  
Novel Applications ◽  
Fixed Beam ◽  
Aberration Corrected

The last decade has witnessed a revolution in electron microscopy as online correction of spherical aberration has become a reality in both fixed-beam and scanning instruments. The combination of improved resolution and higher beam currents coupled with the prospect of simpler image interpretation has stimulated great interest and excitement across the entire field of microscopy. The Microscopy Society of America has an active Focused Interest Group on the topic of “Materials Research in an Aberration-Free Environment,” and its goal is to provide a forum for discussion and dissemination of the latest advances in instrumentation and novel applications of aberration-corrected electron microscopy. This special issue of Microscopy and Microanalysis contains contributions from the Pre-Meeting Congress on this topic held in Chicago, Illinois, in late July 2006, immediately preceding Microscopy & Microanalysis 2006.

The Otto Scherzer Memorial Symposium on Aberration-Corrected Electron Microscopy

2009 ◽  
Vol 17 (5) ◽  
pp. 10-13
Author(s):  
David J. Smith ◽  
Uli Dahmen
Keyword(s):  
Electron Microscopy ◽  
Historical Context ◽  
Aberration Correction ◽  
Short Account ◽  
Memorial Symposium ◽  
Rotationally Symmetric ◽  
Chromatic Aberrations ◽  
Poster Presentations ◽  
Fixed Beam ◽  
Aberration Corrected

The year 2009 marks the centenary of the birth of Otto Scherzer, one of the early pioneers of electron microscopy. Scherzer, shown in Figure 1, was the originator of the famous microscopy theorem that the spherical and chromatic aberrations of rotationally symmetric electron lenses were unavoidable [1]. In honor of this centennial occasion, we organized a special memorial symposium during the Microscopy & Microanalysis 2009 meeting, which was held in Richmond, Virginia, in late July. The introductory talks of the symposium presented a fascinating mix of firsthand accounts about working with Scherzer in Darmstadt and descriptions of the correction concepts and the early corrector prototypes that emerged from his group. Placed in this historical context, the latest advances in aberration correction for scanning and fixed-beam instruments that were presented in this symposium were all the more impressive and conveyed a vivid sense of history in the making. Representative applications of aberration correction to a broad range of materials were also highlighted in platform and poster presentations. Here we give a short account of the emergence of aberration-corrected electron microscopy (ACEM) and very briefly summarize some of the prospects and challenges for this burgeoning field. Further information about these developments, including details of applications, will be found in selected papers from the symposium, which will be published in a forthcoming issue of the journal Microscopy and Microanalysis due to appear in mid-2010.

Electron Holography Improving Transmission Electron Microscopy

1990 ◽  
Vol 48 (1) ◽  
pp. 208-209
Author(s):  
Hannes Lichte
Keyword(s):  
Electron Microscopy ◽  
Transfer Functions ◽  
Imaging System ◽  
Spherical Aberration ◽  
Image Plane ◽  
Chromatic Aberration ◽  
Object Wave ◽  
Objective Lens ◽  
Electron Holography ◽  
Wave Aberration

Generally, the electron object wave o(r) is modulated both in amplitude and phase. In the image plane of an ideal imaging system we would expect to find an image wave b(r) that is modulated in exactly the same way, i. e. b(r) =o(r). If, however, there are aberrations, the image wave instead reads as b(r) =o(r) * FT(WTF) i. e. the convolution of the object wave with the Fourier transform of the wave transfer function WTF . Taking into account chromatic aberration, illumination divergence and the wave aberration of the objective lens, one finds WTF(R) = Echrom(R)Ediv(R).exp(iX(R)) . The envelope functions Echrom(R) and Ediv(R) damp the image wave, whereas the effect of the wave aberration X(R) is to disorder amplitude and phase according to real and imaginary part of exp(iX(R)) , as is schematically sketched in fig. 1.Since in ordinary electron microscopy only the amplitude of the image wave can be recorded by the intensity of the image, the wave aberration has to be chosen such that the object component of interest (phase or amplitude) is directed into the image amplitude. Using an aberration free objective lens, for X=0 one sees the object amplitude, for X= π/2 (“Zernike phase contrast”) the object phase. For a real objective lens, however, the wave aberration is given by X(R) = 2π (.25 Csλ3R4 + 0.5ΔzλR2), Cs meaning the coefficient of spherical aberration and Δz defocusing. Consequently, the transfer functions sin X(R) and cos(X(R)) strongly depend on R such that amplitude and phase of the image wave represent only fragments of the object which, fortunately, supplement each other. However, recording only the amplitude gives rise to the fundamental problems, restricting resolution and interpretability of ordinary electron images:

scholarly journals Direct imaging of lithium atoms in LiV2O4 by spherical aberration-corrected electron microscopy

Microscopy ◽  
2010 ◽  
Vol 59 (6) ◽  
pp. 457-461 ◽  
Author(s):  
Yoshifumi Oshima ◽  
Hidetaka Sawada ◽  
Fumio Hosokawa ◽  
Eiji Okunishi ◽  
Toshikatsu Kaneyama ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Spherical Aberration ◽  
Direct Imaging ◽  
Aberration Corrected

From Nanoparticles to Process: An Aberration-Corrected TEM Study of Fischer-Tropsch Catalysts at Various Steps of the Process

2011 ◽  
Vol 324 ◽  
pp. 197-200 ◽  
Author(s):  
Nadi Braidy ◽  
Carmen Andrei ◽  
Jasmin Blanchard ◽  
Nicolas Abatzoglou
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Amorphous Carbon ◽  
Spherical Aberration ◽  
Fischer Tropsch ◽  
Ft Synthesis ◽  
Transmission Electron ◽  
Treatment Step ◽  
Aberration Corrected

χThe nanostructure of Fischer-Tropsch (FT) Fe carbides are investigated using aberration-corrected high-resolution transmission electron microscopy (TEM). The plasma-generated Fe carbides are analyzed just after synthesis, following reduction via a H2 treatment step and once used as FT catalyst and deactivated. The as-produced nanoparticles (NPs) are seen to be abundantly covered with graphitic and amorphous carbon. Using the extended information limit from the spherical aberration-corrected TEM, the NPs could be indexed as a mixture of NPs in the θ-Fe3C and χ–Fe5C2 phases. The reduction treatment exposed the NPs by removing most of the carbonaceous speSubscript textcies while retaining the χ–Fe5C2. Fe-carbides NPs submitted to conditions typical to FT synthesis develop a Fe3O4 shell which eventually consumes the NPs up to a point where 3-4 nm residual carbide is left at the center of the particle. Subscript textVarious mechanisms explaining the formation of such a microstructure are discussed.

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