ELUCIDATION OF DISLOCATION CORE STRUCTURES IN SILICON BY HIGH RESOLUTION ELECTRON MICROSCOPY

1983 ◽  
Vol 44 (C4) ◽  
pp. C4-3-C4-13 ◽  
Author(s):  
G. L. Hutchison
2006 ◽  
Vol 203 (9) ◽  
pp. 2156-2160 ◽  
Author(s):  
J. Kioseoglou ◽  
G. P. Dimitrakopulos ◽  
Ph. Komninou ◽  
Th. Kehagias ◽  
Th. Karakostas

2005 ◽  
Vol 482 ◽  
pp. 39-44 ◽  
Author(s):  
Martin J. Hÿtch ◽  
Jean-Luc Putaux ◽  
Jean-Michel Pénisson

The geometric phase technique (GPA) for measuring the distortion of crystalline lattices from high-resolution electron microscopy (HRTEM) images will be described. The method is based on the calculation of the “local” Fourier components of the HRTEM image by filtering in Fourier space. The method will be illustrated with a study of an edge dislocation in silicon where displacements have been measured to an accuracy of 3 pm at nanometre resolution as compared with anisotropic elastic theory calculations. The different components of the strain tensor will be mapped out in the vicinity of the dislocation core and compared with theory. The accuracy is of the order of 0.5% for strain and 0.1° for rigid-body rotations. Using bulk elastic constants for silicon, the stress field is determined to 0.5 GPa at nanometre spatial resolution. Accuracy and the spatial resolution of the technique will be discussed.


Author(s):  
D.J.H. Cockayne ◽  
G.R. Anstis

The interpretation of high resolution (0.5nm) image detail to study dislocation cores relies upon image calculations for its justification. The scattering equations used to calculate these images make use of various approximations, and their validity at this level of resolution has been in doubt. Because of this, a detailed study has been made of the various methods of image calculation, and the reliability of image interpretation for a number of experimental situations has been determined.Images of dislocations of arbitrary resolution can be calculated by an extension of the approach considered by Howie and Basinski. Given an expansion of the potential V(r) = Σgvg(r) exp (2Πig.r) and wavefunctionsthen, for a given incident wavefunction, the wavefunction ψ(r) = Σgϕg(r) exp (2Πig.r) is the unique solution to the form of Schroedinger's equation in which backscattering is neglected, irrespective of the extent of lattice distortion.


1982 ◽  
Vol 14 ◽  
Author(s):  
J. M. Gibson ◽  
R. T. Tung ◽  
J. M. Poate

ABSTRACTWe have studied interface atomic structure in epitaxial cobalt and nickel disilicides on silicon using high-resolution transmission electron microscopy. By employing UHV techniques during deposition and reaction we have grown truly single-crystalline NiSi2 and CoSi2 films on (111) Si and in the former case on (100) Si. These films are shown to be continuous to below 10Å thickness. By close control over preparation conditions, afforded by UHV, we can greatly influence the nucleation and growth of these films to the extent, for example with NiSi2 on (111)Si, of yielding continuous single-crystal films with either of two orientations as desired. Whilst in the (111) NiSi2 on Si system the interfacial structure invariably appears to well-fit a model in which metal atoms nearest to the interface are 7-fold co-ordinated, for (111) CoSi2 on Si agreement is generally better with a model involving 5-fold co-ordination of these atoms. A misfit dislocation core is also imaged. Results are discussed in the light of silicide nucleation and growth. The structure and stability of the (100) NiSi2 on Si interface is also considered.


1988 ◽  
Vol 133 ◽  
Author(s):  
Martin A. Crimp ◽  
P. M. Hazzledine

ABSTRACTHigh resolution electron microscopy has been used to study the core structure of a/2[101] and a/3<112> dislocations in Ni3Al deformed in the range of increasing strength with temperature. a/3<112> coupled SISFs were found to lie on (111) and their structure agreed well with theoretical predictions. a/2[101] superpartials were always dissociated on (111) or (111) planes while the APB plane was found to be (010). Computer simulation of dislocation core structures were found to agree well with the observed dissociations. The APB width was found to increase significantly with increasing deformation temperature near the peak yield strength temperature.


Author(s):  
W. H. Wu ◽  
R. M. Glaeser

Spirillum serpens possesses a surface layer protein which exhibits a regular hexagonal packing of the morphological subunits. A morphological model of the structure of the protein has been proposed at a resolution of about 25 Å, in which the morphological unit might be described as having the appearance of a flared-out, hollow cylinder with six ÅspokesÅ at the flared end. In order to understand the detailed association of the macromolecules, it is necessary to do a high resolution structural analysis. Large, single layered arrays of the surface layer protein have been obtained for this purpose by means of extensive heating in high CaCl2, a procedure derived from that of Buckmire and Murray. Low dose, low temperature electron microscopy has been applied to the large arrays.As a first step, the samples were negatively stained with neutralized phosphotungstic acid, and the specimens were imaged at 40,000 magnification by use of a high resolution cold stage on a JE0L 100B. Low dose images were recorded with exposures of 7-9 electrons/Å2. The micrographs obtained (Fig. 1) were examined by use of optical diffraction (Fig. 2) to tell what areas were especially well ordered.


Author(s):  
Robert A. Grant ◽  
Laura L. Degn ◽  
Wah Chiu ◽  
John Robinson

Proteolytic digestion of the immunoglobulin IgG with papain cleaves the molecule into an antigen binding fragment, Fab, and a compliment binding fragment, Fc. Structures of intact immunoglobulin, Fab and Fc from various sources have been solved by X-ray crystallography. Rabbit Fc can be crystallized as thin platelets suitable for high resolution electron microscopy. The structure of rabbit Fc can be expected to be similar to the known structure of human Fc, making it an ideal specimen for comparing the X-ray and electron crystallographic techniques and for the application of the molecular replacement technique to electron crystallography. Thin protein crystals embedded in ice diffract to high resolution. A low resolution image of a frozen, hydrated crystal can be expected to have a better contrast than a glucose embedded crystal due to the larger density difference between protein and ice compared to protein and glucose. For these reasons we are using an ice embedding technique to prepare the rabbit Fc crystals for molecular structure analysis by electron microscopy.


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