Atomic Structures of Oxygen-associated Defects in Sintered Aluminum Nitride Ceramics

Convergent-beam electron diffraction and Z-contrast imaging are used to study oxygen-associated defects, flat inversion domain boundaries, dislocations, and interfaces in sintered AlN ceramics. The structures of these defects are directly derived from atomic-resolution Z-contrast images. The flat inversion domain boundaries contain a single Al-O octahedral layer and have a stacking sequence of . . .bAaB-bAc-CaAc. . , where -cAb- indicates the single octahedral layer. The expansion at the flat inversion domain boundaries is measured to be 0.06 (±0.02) nm. The interfaces between 2H- and polytypoid-AlN are found to be also inversion domain boundaries but their stacking sequence differs from that of the flat inversion domain boundaries.

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Inversion Domain Boundaries in GaN Grown on Sapphire

MRS Proceedings ◽

10.1557/proc-449-423 ◽

1996 ◽

Vol 449 ◽

Cited By ~ 7

Author(s):

L. T. Romano ◽

J.E. Northrup

Keyword(s):

Dark Field ◽

Hydride Vapor Phase Epitaxy ◽

Dark Field Imaging ◽

Inversion Domain ◽

Transmission Electron ◽

Domain Boundaries ◽

Convergent Beam ◽

Inversion Domain Boundaries ◽

Field Imaging ◽

Beam Diffraction

ABSTRACTInversion domain boundaries (IDBs) in GaN grown on sapphire (0001) were studied by a combination of high resolution transmission electron microscopy, multiple dark field imaging, and convergent beam diffraction. Films grown by molecular beam epitaxy (MBE), metalorganic vapor deposition (MOCVD), and hydride vapor phase epitaxy (HVPE) were investigated and all found to contain IDBs. Inversion domains (IDs) that extended from the surface to the interface were found to be columnar with facets on the {10–10} and {11–20} planes. Other domains ended within the film that formed IDBs on the (0001) and {1–102} planes. The domains were found to grow in clusters and connect at points along the boundary.

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Planar and Curved Defects in Aluminum Nitride: Their Microstructure and Microchemistry

MRS Proceedings ◽

10.1557/proc-167-265 ◽

1989 ◽

Vol 167 ◽

Cited By ~ 1

Author(s):

Alistair D. Westwood ◽

Michael R. Notis

Keyword(s):

Electron Microscopy ◽

Aluminum Nitride ◽

Analytical Electron Microscopy ◽

Microchemical Analysis ◽

Inversion Domain ◽

Transmission Electron ◽

Proposed Model ◽

Domain Boundaries ◽

Convergent Beam ◽

Inversion Domain Boundaries

AbstractThe microstructure and microchemistry of planar and curved defects in Aluminum Nitride (AIN) has been investigated using Conventional Transmission Electron Microscopy (CTEM), Convergent Beam Electron Diffraction (CBED), and Analytical Electron Microscopy (AEM) techniques. Both defect morphologies were identified as Inversion Domain Boundaries (IDB). Microchemical analysis revealed oxygen segregation to the planar faults; when present on the curved defects, oxygen was at a lower concentration than in the planar defect case. Annealing experiments on defect containing AIN support our microchemical analysis of oxygen segregation. A proposed model for the formation of these two types of boundaries is presented.

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Atomic Structures of Inversion Domain Boundaries and Dislocations in Sintered ALN

Microscopy and Microanalysis ◽

10.1017/s1431927600024065 ◽

1998 ◽

Vol 4 (S2) ◽

pp. 788-789

Author(s):

Yanfa Yan ◽

M. F. Chisholm ◽

S. J. Pennycook

Keyword(s):

Direct Determination ◽

Data Interpretation ◽

Scanning Transmission Electron Microscope ◽

Extended Defects ◽

Contrast Imaging ◽

Fringe Contrast ◽

Inversion Domain ◽

Domain Boundaries ◽

Scanning Transmission ◽

Inversion Domain Boundaries

A1N is an attractive material because of its mechanical, thermal and electronic properties. However, these properties are often adversely altered by extended defects such as inversion domain boundaries (IDBs), and through impurities associated with the defects, especially oxygen. Thus to improve the properties of the material it is important to understand the structures of the defects. A number of studies have been carried out to characterize these defects using fringe contrast, weak-beam, convergent-beam electron diffraction and conventional high-resolution phase contrast imaging. These techniques all require the use of model structures for data interpretation. In this paper, we report a direct determination of the structures of IDBs and dislocation cores in A1N by highresolution Z-contrast imaging using a 300 kV VG HB603U scanning transmission electron microscope, with a probe size of 1.3 Å.

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Glide Dislocations Dissociation in Inversion Domain Boundaries of Plastically Deformed Aluminium Nitride

Journal de Physique III ◽

10.1051/jp3:1996184 ◽

1996 ◽

Vol 6 (9) ◽

pp. 1261-1269 ◽

Cited By ~ 3

Author(s):

Virginia Feregotto ◽

Jean-Pierre Michel

Keyword(s):

Aluminium Nitride ◽

Inversion Domain ◽

Domain Boundaries ◽

Inversion Domain Boundaries

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Inversion domain boundaries in wurtzite GaN

Physical Review B ◽

10.1103/physrevb.103.165305 ◽

2021 ◽

Vol 103 (16) ◽

Author(s):

M. M. F. Umar ◽

Jorge O. Sofo

Keyword(s):

Inversion Domain ◽

Domain Boundaries ◽

Inversion Domain Boundaries

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Interaction Between Basal Stacking Faults and Prismatic Inversion Domain Boundaries in GaN

MRS Proceedings ◽

10.1557/proc-639-g3.44 ◽

2000 ◽

Vol 639 ◽

Cited By ~ 1

Author(s):

Philomela Komninou ◽

Joseph Kioseoglou ◽

Eirini Sarigiannidou ◽

George P. Dimitrakopulos ◽

Thomas Kehagias ◽

...

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Stacking Faults ◽

High Resolution Electron Microscopy ◽

High Energy ◽

Low Energy ◽

Inversion Domain ◽

Resolution Electron ◽

Domain Boundaries ◽

Inversion Domain Boundaries

ABSTRACTThe interaction of growth intrinsic stacking faults with inversion domain boundaries in GaN epitaxial layers is studied by high resolution electron microscopy. It is observed that stacking faults may mediate a structural transformation of inversion domain boundaries, from the low energy types, known as IDB boundaries, to the high energy ones, known as Holt-type boundaries. Such interactions may be attributed to the different growth rates of adjacent domains of inverse polarity.

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Junction lines of inversion domain boundaries with stacking faults in GaN

Physical Review B ◽

10.1103/physrevb.70.115331 ◽

2004 ◽

Vol 70 (11) ◽

Cited By ~ 10

Author(s):

J. Kioseoglou ◽

G. P. Dimitrakopulos ◽

Ph. Komninou ◽

H. M. Polatoglou ◽

A. Serra ◽

...

Keyword(s):

Stacking Faults ◽

Inversion Domain ◽

Domain Boundaries ◽

Inversion Domain Boundaries

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Incoherent High-Resolution Z-Contrast Imaging of Silicon and Gallium Arsenide Using HAADF-STEM

MRS Proceedings ◽

10.1557/proc-589-185 ◽

1999 ◽

Vol 589 ◽

Author(s):

Y Kotaka ◽

T. Yamazaki ◽

Y Kikuchi ◽

K. Watanabe

Keyword(s):

Scanning Transmission Electron Microscope ◽

Dark Field ◽

Contrast Imaging ◽

High Spatial Resolution Image ◽

Transmission Electron ◽

Eigen Value ◽

Scanning Transmission ◽

Annular Dark Field ◽

Convergent Beam ◽

Z Contrast

AbstractThe high-angle annular dark-field (HAADF) technique in a dedicated scanning transmission electron microscope (STEM) provides strong compositional sensitivity dependent on atomic number (Z-contrast image). Furthermore, a high spatial resolution image is comparable to that of conventional coherent imaging (HRTEM). However, it is difficult to obtain a clear atomic structure HAADF image using a hybrid TEM/STEM. In this work, HAADF images were obtained with a JEOL JEM-2010F (with a thermal-Schottky field-emission) gun in probe-forming mode at 200 kV. We performed experiments using Si and GaAs in the [110] orientation. The electron-optical conditions were optimized. As a result, the dumbbell structure was observed in an image of [110] Si. Intensity profiles for GaAs along [001] showed differences for the two atomic sites. The experimental images were analyzed and compared with the calculated atomic positions and intensities obtained from Bethe's eigen-value method, which was modified to simulate HAADF-STEM based on Allen and Rossouw's method for convergent-beam electron diffraction (CBED). The experimental results showed a good agreement with the simulation results.

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Microstructral Investigations on GaN Films Grown by Laser Induced Molecular Beam Epitaxy

MRS Proceedings ◽

10.1557/proc-595-f99w3.58 ◽

1999 ◽

Vol 595 ◽

Cited By ~ 1

Author(s):

H. Zhou ◽

F. Phillipp ◽

M. Gross ◽

H. Schröder

Keyword(s):

Molecular Beam Epitaxy ◽

Molecular Beam ◽

Threading Dislocations ◽

Planar Defects ◽

Sapphire Substrates ◽

Inversion Domain ◽

Transmission Electron ◽

Domain Boundaries ◽

Line Defects ◽

Inversion Domain Boundaries

AbstractMicrostructural investigations on GaN films grown on SiC and sapphire substrates by laser induced molecular beam epitaxy have been performed. Threading dislocations with Burgers vectors of 1/3<1120>, 1/3<1123> and [0001] are typical line defects, predominantly the first type of dislocations. Their densities are typically 1.5×1010 cm−2 and 4×109 cm−2 on SiC and sapphire, respectively. Additionally, planar defects characterized as inversion domain boundaries lying on {1100} planes have been observed in GaN/sapphire samples with an inversion domain density of 4×109 cm−2. The inversion domains are of Ga-polarity with respect to the N-polarity of the adjacent matrix. However, GaN layers grown on SiC show Ga-polarity. Possible reasons for the different morphologies and structures of the films grown on different substrates are discussed. Based on an analysis of displacement fringes of inversion domains, an atomic model of the IDB-II with Ga-N bonds across the boundary was deduced. High resolution transmission electron microscopy (HRTEM) observations and the corresponding simulations confirmed the IDB-II structure determined by the analysis of displacement fringes.

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