Dr. Probe: A software for high-resolution STEM image simulation

In a STEM an electron beam is focused into a small probe on the specimen. This probe is raster scanned across the specimen to form an image from the electrons transmitted through the specimen. The objective lens is positioned before the specimen instead of after the specimen as in a CTEM. Because the probe is focused and scanned before the specimen, accurate annular dark field (ADF) STEM image simulation is more difficult than CTEM simulation. Instead of an incident uniform plane wave, ADF-STEM simulation starts with a probe wavefunction focused at a specified position on the specimen. The wavefunction is then propagated through the specimen one atomic layer (or slice) at a time with Fresnel diffraction between slices using the multislice method. After passing through the specimen the wavefunction is diffracted onto the detector. The ADF signal for one position of the probe is formed by integrating all electrons scattered outside of an inner angle large compared with the objective aperture.

Download Full-text

Computers and diffraction analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100152197 ◽

1989 ◽

Vol 47 ◽

pp. 44-45

Author(s):

J. A. Eades

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Electron Diffraction ◽

Diffraction Analysis ◽

Electron Diffraction Analysis ◽

Image Simulation ◽

Correct Interpretation ◽

High Profile ◽

High Resolution Images ◽

Image Simulations

For well over two decades computers have played an important role in electron microscopy; they now pervade the whole field - as indeed they do in so many other aspects of our lives. The initial use of computers was mainly for large (as it seemed then) off-line calculations for image simulations; for example, of dislocation images.Image simulation has continued to be one of the most notable uses of computers particularly since it is essential to the correct interpretation of high resolution images. In microanalysis, too, the computer has had a rather high profile. In this case because it has been a necessary part of the equipment delivered by manufacturers. By contrast the use of computers for electron diffraction analysis has been slow to prominence. This is not to say that there has been no activity, quite the contrary; however it has not had such a great impact on the field.

Download Full-text

High-resolution z-contrast imaging of semiconductor interfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100154317 ◽

1989 ◽

Vol 47 ◽

pp. 468-469

Author(s):

S. J. Pennycook

Keyword(s):

High Resolution ◽

Phase Contrast ◽

Contrast Imaging ◽

Compositional Modulation ◽

Semiconductor Interfaces ◽

Complex Figure ◽

Thin Region ◽

Stem Image ◽

Annular Detector ◽

Z Contrast

Using a high-angle annular detector on a high-resolution STEM it is possible to form incoherent images of a crystal lattice characterized by strong atomic number or Z contrast. Figure 1 shows an epitaxial Ge film on Si(100) grown by oxidation of Ge-implanted Si. The image was obtained using a VG Microscopes' HB501 STEM equipped with an ultrahigh resolution polepiece (Cs ∽1.2 mm, demonstrated probe FWHM intensity ∽0.22 nm). In both crystals the lattice is resolved but that of Ge shows much brighter allowing the interface to be located exactly and interface steps to be resolved (arrowed). The interface was indistinguishable in the phase-contrast STEM image from the same region, and even at higher resolution the location of the interface is complex. Figure 2 shows a thin region of an MBE-grown ultrathin super-lattice (Si8Ge2)100. The expected compositional modulation would show as one bright row of dots from the 2 Ge monolayers separated by 4 rows of lighter Si columns. The image shows clearly that strain-induced interdiffusion has occurred on the monolayer scale.

Download Full-text

Automatic Registering and Stitching of TEM/STEM Image Mosaics

ISTFA 2013: Conference Proceedings from the 39th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2013p0152 ◽

2013 ◽

Author(s):

Chung-Ching Lin ◽

Franco Stellari ◽

Lynne Gignac ◽

Peilin Song ◽

John Bruley

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Vlsi Circuit ◽

Significant Progress ◽

Research Areas ◽

Automated Method ◽

Transmission Electron ◽

Stem Image ◽

High Resolution Images ◽

Global Optimal

Abstract Transmission Electron Microscopy (TEM) and scanning TEM (STEM) is widely used to acquire ultra high resolution images in different research areas. For some applications, a single TEM/STEM image does not provide enough information for analysis. One example in VLSI circuit failure analysis is the tracking of long interconnection. The capability of creating a large map of high resolution images may enable significant progress in some tasks. However, stitching TEM/STEM images in semiconductor applications is difficult and existing tools are unable to provide usable stitching results for analysis. In this paper, a novel fully automated method for stitching TEM/STEM image mosaics is proposed. The proposed method allows one to reach a global optimal configuration of each image tile so that both missing and false-positive correspondences can be tolerated. The experiment results presented in this paper show that the proposed method is robust and performs well in very challenging situations.

Download Full-text

Including Thermal Vibrations and Bonding in HAADF-STEM Image Simulation

Microscopy and Microanalysis ◽

10.1017/s1431927614002499 ◽

2014 ◽

Vol 20 (S3) ◽

pp. 154-155 ◽

Cited By ~ 1

Author(s):

Michael Odlyzko ◽

K. Andre Mkhoyan

Keyword(s):

Image Simulation ◽

Stem Image ◽

Thermal Vibrations

Download Full-text

Combined Experimentaland Theoretical Determination of the Atomic Structure of the (310) Twin in NB

MRS Proceedings ◽

10.1557/proc-238-163 ◽

1991 ◽

Vol 238 ◽

Cited By ~ 3

Author(s):

Geoffrey H. Campbells ◽

Wayne E. King ◽

Stephen M. Foiles ◽

Peter Gumbsch ◽

Manfred Rühle

Keyword(s):

High Resolution ◽

Theoretical Models ◽

High Resolution Electron Microscopy ◽

Interatomic Potentials ◽

Image Simulation ◽

Theoretical Determination ◽

Atomic Structures ◽

Resolution Electron ◽

High Resolution Images

ABSTRACTA (310) twin boundary in Nb has been fabricated by diffusion bonding oriented single crystals and characterized using high resolution electron microscopy. Atomic structures for the boundary have been predicted using different interatomic potentials. Comparison of the theoretical models to the high resolution images has been performed through image simulation. On the basis of this comparison, one of the low energy structures predicted by theory can be ruled out.

Download Full-text