Analysis of dislocation loops by means of large-angle convergent beam electron diffraction

Jäger, C.; Spiecker, Erdmann; Morniroli, J. P.; Jäger, W.

doi:10.1088/0953-8984/14/48/316

Cited by 8 publications

(7 citation statements)

References 10 publications

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“…If g•b is positive, the line bends toward the s > 0 direction (Cherns & Preston, 1989;Jäger et al, 2002). The positive bending direction is indicated in all LACBED patterns.…”

Section: Methodsmentioning

confidence: 92%

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Burgers Vector Analysis of Vertical Dislocations in Ge Crystals by Large-Angle Convergent Beam Electron Diffraction

et al. 2015

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By transmission electron microscopy with extended Burgers vector analyses, we demonstrate the edge and screw character of vertical dislocations (VDs) in novel SiGe heterostructures. The investigated pillar-shaped Ge epilayers on prepatterned Si(001) substrates are an attempt to avoid the high defect densities of lattice mismatched heteroepitaxy. The Ge pillars are almost completely strain-relaxed and essentially defect-free, except for the rather unexpected VDs. We investigated both pillar-shaped and unstructured Ge epilayers grown either by molecular beam epitaxy or by chemical vapor deposition to derive a general picture of the underlying dislocation mechanisms. For the Burgers vector analysis we used a combination of dark field imaging and large-angle convergent beam electron diffraction (LACBED). With LACBED simulations we identify ideally suited zeroth and second order Laue zone Bragg lines for an unambiguous determination of the three-dimensional Burgers vectors. By analyzing dislocation reactions we confirm the origin of the observed types of VDs, which can be efficiently distinguished by LACBED. The screw type VDs are formed by a reaction of perfect 60° dislocations, whereas the edge types are sessile dislocations that can be formed by cross-slips and climbing processes. The understanding of these origins allows us to suggest strategies to avoid VDs.

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“…If g•b is positive, the line bends toward the s > 0 direction (Cherns & Preston, 1989;Jäger et al, 2002). The positive bending direction is indicated in all LACBED patterns.…”

Section: Methodsmentioning

confidence: 92%

“…The sign of n describes the bending direction of the splitting and is linked to the sign of the deviation parameter s . If g • b is positive, the line bends toward the s>0 direction (Cherns & Preston, 1989; Jäger et al, 2002). The positive bending direction is indicated in all LACBED patterns.…”

Section: Methodsmentioning

confidence: 99%

Burgers Vector Analysis of Vertical Dislocations in Ge Crystals by Large-Angle Convergent Beam Electron Diffraction

et al. 2015

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“…For the analysis of large and isolated loops, there are no difficulties and the behaviour is the same as for perfect or partial dislocations (Jäger et al ., 2002). With small loops (with a size smaller than 100 nm) two main difficulties are encountered.…”

Section: Analysis Of Defectsmentioning

confidence: 99%

CBED and LACBED characterization of crystal defects

Morniroli

2006

Journal of Microscopy

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Summary Convergent‐beam electron diffraction (CBED) obtained with a focused incident beam is well known for the identification of the point and space groups but it can also be used for the analysis of stacking faults and antiphase boundaries. Large‐angle convergent‐beam electron diffraction (LACBED) is performed with a large defocused incident beam and is well adapted to the characterization of most types of crystal defects: point defects, perfect and partial dislocations, stacking faults, antiphase boundaries and grain boundaries. Among the advantages of these methods with respect to the conventional transmission electron microscopy methods, are that one or few patterns are required for a full analysis and the interpretations are easy and unambiguous. The LACBED technique is particularly useful for the analysis of dislocations present in anisotropic and beam‐sensitive materials.

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“…So far, the method has been successfully applied to relatively large and isolated dislocation loops present in semiconductors (Tanaka et al ., 1988; Jäger et al ., 2002). However, experimental difficulty is encountered with the analysis of small dislocation loops.…”

Section: Introductionmentioning

confidence: 99%

New developments in the characterization of dislocation loops from LACBED patterns

Morniroli

Marceau

Ringer

2006

Journal of Microscopy

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Summary The characterization of the Burgers vector of dislocations from large‐angle convergent‐beam electron diffraction (LACBED) patterns is now a well‐established method. The method has already been applied to relatively large and isolated dislocation loops in semiconductors. Nevertheless, some severe experimental difficulties are encountered with small dislocation loops. By using a 2 µm selected‐area aperture and a carbon contamination point to mark the loop of interest, we were able to characterize both the plane and the Burgers vector of dislocation loops of a few tens of nanometres in size present in Al‐Cu‐Mg alloys.

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Analysis of dislocation loops by means of large-angle convergent beam electron diffraction

Cited by 8 publications

References 10 publications

Burgers Vector Analysis of Vertical Dislocations in Ge Crystals by Large-Angle Convergent Beam Electron Diffraction

Burgers Vector Analysis of Vertical Dislocations in Ge Crystals by Large-Angle Convergent Beam Electron Diffraction

CBED and LACBED characterization of crystal defects

New developments in the characterization of dislocation loops from LACBED patterns

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