Characterization of Contacting Boundaries between Nanoparticles with LACBED

2003 ◽  
Vol 9 (3) ◽  
pp. 237-244 ◽  
Author(s):  
Yiming Yao ◽  
Anders R. Thölén
Keyword(s):  
Nanocrystalline Materials ◽  
Large Angle ◽  
Convergent Beam Electron Diffraction ◽  
Average Accuracy ◽  
Accuracy Of Measurements ◽  
Wide Range ◽  
Grain Orientations ◽  
Rotation Parameters ◽  
Convergent Beam

The boundary parameters between contacting spherical bcc-Fe particles have been characterized with the Large Angle Convergent Beam Electron Diffraction (LACBED) technique. The average accuracy of measurements can reach 0.07°. The rotation parameters are interpreted using matrix algebra and evaluated according to the CSL model. The deviation between the experimental results and the reference misorientations given in the CSL model is determined. It is possible to reveal preferential misorientations between irregularly shaped particles with a size less than 100 nm. The method can be applied to nanoparticles and nanocrystalline materials with a wide range of grain orientations, and it is possible to modify it into an automatic method for TEM measurements.

Characterization of Threading Screw Dislocations of Burgers Vectors with A-Components in 4H-SiC

2016 ◽  
Vol 858 ◽  
pp. 401-404 ◽  
Author(s):  
Shoichi Onda ◽  
Takeshi Okamoto ◽  
Hideyuki Uehigashi ◽  
Hiroyuki Kondo ◽  
Hiroyasu Saka
Keyword(s):  
Dislocation Line ◽  
Large Angle ◽  
Convergent Beam Electron Diffraction ◽  
Device Performance ◽  
Screw Dislocations ◽  
Burgers Vector ◽  
New Type ◽  
Convergent Beam ◽  
Good Agreement

We characterized threading screw dislocations to investigate the influence on device performance. The Burgers vectors of the threading screw dislocations (a total of 28dislocations) in 4H-SiC were determined by large-angle convergent-beam electron diffraction. A new type of TSD, b=c+2a dislocation was identified. And all of the four types of TSD predicted were identified. The frequency of their occurrence observed experimentally is in good agreement with theoretical prediction. In addition, we investigated relations of Burgers vector and the dislocation line direction.　 It has been confirmed that the Burgers vector of TSD does not necessarily coincide with the direction of dislocation lines. Looking ahead,　we need to investigate how the angle between Burgers vector and dislocation line influence device performance.

Applications of C-AFM and CBED Techniques to the Characterization of Substrate Dislocations Causing SRAM Soft Single-Column Failure Contained in a Wafer with (001) Plane/[100] Notch

2008 ◽  
Author(s):  
Hung-Sung Lin ◽  
Tung-Hung Chen ◽  
Wen-Cheng Shu
Keyword(s):  
Electron Diffraction ◽  
Process Development ◽  
Large Angle ◽  
Convergent Beam Electron Diffraction ◽  
Fault Isolation ◽  
Beam Electron ◽  
Atomic Force ◽  
Single Column ◽  
Convergent Beam

Abstract SRAM memory is an ideal vehicle for defect monitoring and yield improvement during process development because of its highly structured architecture. However, the success rate of defect detection, especially for soft single-column failures, is decreasing when traditional physical failure analysis (PFA) with only the bitmap is available for guidance. This is due to a variety of invisible or undetectable defects that cause leakage in the device. In order to understand the leakage behavior in advanced high voltage (HV) processes, a Conductive Atomic Force Microscope (C-AFM) [1-4] is introduced to perform junction-level fault isolation prior to attempting PFA. According to J. P. Morniroli [5], crystalline defects affect convergent-beam electron diffraction (CBED) and large angle convergent-beam electron diffraction (LACBED) patterns, so CBED and LACBED techniques were also applied to the specimens containing dislocations to allow further characterization of these defects. In this study quantified data extracted using the C-AFM is also used to establish a connection between the failure mechanism discovered and the soft single column failure mode.

Strain measurement by means of bend contour microscopy

1989 ◽  
Vol 47 ◽  
pp. 210-211
Author(s):  
Philip D. Hren
Keyword(s):  
Strain Measurement ◽  
Large Angle ◽  
Single Crystal Silicon ◽  
Convergent Beam Electron Diffraction ◽  
Zone Axis ◽  
Silicon Membrane ◽  
Crystal Silicon ◽  
Contour Pattern ◽  
Convergent Beam ◽  
Low Symmetry

The pattern of bend contours which appear in the TEM image of a bent or curled sample indicates the shape into which the specimen is bent. Several authors have characterized the shape of their bent foils by this method, most recently I. Bolotov, as well as G. Möllenstedt and O. Rang in the early 1950’s. However, the samples they considered were viewed at orientations away from a zone axis, or at zone axes of low symmetry, so that dynamical interactions between the bend contours did not occur. Their calculations were thus based on purely geometric arguments. In this paper bend contours are used to measure deflections of a single-crystal silicon membrane at the (111) zone axis, where there are strong dynamical effects. Features in the bend contour pattern are identified and associated with a particular angle of bending of the membrane by reference to large-angle convergent-beam electron diffraction (LACBED) patterns.

Large-angle convergent-beam electron-diffraction study of coherent precipitates and decorated dislocations

1996 ◽  
Vol 54 ◽  
pp. 1002-1004
Author(s):  
J.M.K. Wiezorek ◽  
H.L. Fraser
Keyword(s):  
Electron Diffraction ◽  
Angular Resolution ◽  
Large Angle ◽  
Electron Diffraction Study ◽  
Convergent Beam Electron Diffraction ◽  
Crystal Defects ◽  
High Angular Resolution ◽  
Beam Electron ◽  
Diffraction Plane ◽  
Convergent Beam

Conventional methods of convergent beam electron diffraction (CBED) use a fully converged probe focused on the specimen in the object plane resulting in the formation of a CBED pattern in the diffraction plane. Large angle CBED (LACBED) uses a converged but defocused probe resulting in the formation of ‘shadow images’ of the illuminated sample area in the diffraction plane. Hence, low-spatial resolution image information and high-angular resolution diffraction information are superimposed in LACBED patterns which enables the simultaneous observation of crystal defects and their effect on the diffraction pattern. In recent years LACBED has been used successfully for the investigation of a variety of crystal defects, such as stacking faults, interfaces and dislocations. In this paper the contrast from coherent precipitates and decorated dislocations in LACBED patterns has been investigated. Computer simulated LACBED contrast from decorated dislocations and coherent precipitates is compared with experimental observations.

A study of twinning in YBa2Cu3O7−x by large-angle convergent-beam electron diffraction

1990 ◽  
Vol 48 (4) ◽  
pp. 20-21
Author(s):  
P.A. Midgley ◽  
R. Vincent ◽  
D. Cherns
Keyword(s):  
Electron Diffraction ◽  
Oxygen Atom ◽  
Strain Field ◽  
Large Angle ◽  
Convergent Beam Electron Diffraction ◽  
Orthorhombic Distortion ◽  
Beam Electron ◽  
Resultant Powder ◽  
Convergent Beam ◽  
Mesh Grid

The oxygenation of YBa2Cu3O7−x (YBCO) leads to an orthorhombic distortion of the unit cell to accommodate the extra oxygen atom. This makes the formation of twins energetically favourable with CuO4 planar unit chains running alternately along the a and b axes of the parent tetragonal structure. The geometry of this twinning is such that four possible twin variants may co-exist with the twin boundaries lying in the (110) or (110) planes of the deformed structure. The traces of these planes are not mutually perpendicular and thus the crystal is strained to allow for the mismatch. It is to the nature of this strain field that this work has been addressed.Sintered samples were prepared by crushing and dispersing the resultant powder onto a very fine Cu mesh grid. Single crystals were chemically thinned to perforation. No discernible artefacts were seen and similar results were obtained with either method.

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