scholarly journals Рентгеноструктурный анализ эпитаксиальных слоев со свойствами дислокационного фильтра

2018 ◽  
Vol 44 (13) ◽  
pp. 19
Author(s):  
И.Д. Лошкарев ◽  
А.П. Василенко ◽  
Е.М. Труханов ◽  
А.В. Колесников ◽  
М.О. Петрушков ◽  
...  
Keyword(s):  
Sharp Decrease ◽  
Epitaxial Films ◽  
Threading Dislocation ◽  
Threading Dislocations ◽  
Gaas Film ◽  
Reciprocal Space Mapping ◽  
X Ray ◽  
Threading Dislocation Density ◽  
Small Angle Boundary ◽  
Low Temperature Gaas

AbstractAn approach to instant testing of epitaxial films with a sharp decrease in the threading dislocation density is proposed. High-resolution X-ray diffractometry, including reciprocal space mapping, has been used. The structure of GaAs/Si(001) heterosystems with low-temperature GaAs layers has been analyzed. A decrease in the density of threading dislocations in the GaAs film with the formation of a small-angle boundary has been detected.

X-Ray Topography Characterization of Large Diameter AlN Single Crystal Substrates

2020 ◽  
Vol 1004 ◽  
pp. 63-68
Author(s):  
Rafael Dalmau ◽  
Jeffrey Britt ◽  
Hao Yang Fang ◽  
Balaji Raghothamachar ◽  
Michael Dudley ◽  
...  
Keyword(s):  
Single Crystal ◽  
Large Diameter ◽  
Grazing Incidence ◽  
Threading Dislocation ◽  
Threading Dislocations ◽  
X Ray ◽  
Dislocation Densities ◽  
Transmission Geometry ◽  
Threading Dislocation Density

Large diameter aluminum nitride (AlN) substrates, up to 50 mm, were manufactured from single crystal boules grown by physical vapor transport (PVT). Synchrotron-based x-ray topography (XRT) was used to characterize the density, distribution, and type of dislocations. White beam topography images acquired in transmission geometry were used to analyze basal plane dislocations (BPDs) and low angle grain boundaries (LAGBs), while monochromatic beam, grazing incidence images were used to analyze threading dislocations. Boule diameter expansion, without the introduction of LAGBs around the periphery, was shown. A 48 mm substrate with a uniform threading dislocation density below 7.0 x 102 cm-2 and a BPD of 0 cm-2, the lowest dislocation densities reported to date for an AlN single crystal this size, was demonstrated.

Threading dislocations in domain-matching epitaxial films of ZnO

2007 ◽  
Vol 40 (5) ◽  
pp. 924-930 ◽  
Author(s):  
W.-R. Liu ◽  
W. F. Hsieh ◽  
C.-H. Hsu ◽  
Keng S. Liang ◽  
F. S.-S. Chien
Keyword(s):  
Gas Flow ◽  
Epitaxial Films ◽  
Zno Films ◽  
Threading Dislocation ◽  
Threading Dislocations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Atomic Force ◽  
Transmission Electron ◽  
Edge Dislocations

The structures of high-quality ZnO epitaxial films grown by pulsed-laser deposition on sapphire (0001) without an oxygen gas flow were investigated by X-ray diffraction and transmission electron microscopy. The great disparity of X-ray diffraction line widths between the normal and in-plane reflections reveals the specific threading dislocation geometry of ZnO. Most threading dislocations are pure edge dislocations. From a combination of scattering and microscopic results, it is found that threading dislocations are not uniformly distributed in the ZnO films, but the films consist of columnar epitaxial cores surrounded by annular regions of edge threading dislocations in large density. The local surface morphology and capacitance signal obtained from atomic force and scanning capacitance microscopes indicate that the aggregation of threading dislocations leads to high interface traps at the annular regions.

Defect Reduction in Cd1-xZnxTe Epilayers on GaAs Substrates

1994 ◽  
Vol 299 ◽  
Author(s):  
Saket Chadda ◽  
Kevin Malloy ◽  
John Reno
Keyword(s):  
Threading Dislocation ◽  
Full Width ◽  
X Ray Diffraction ◽  
Defect Reduction ◽  
X Ray ◽  
Gaas Substrates ◽  
Transmission Electron ◽  
Threading Dislocation Density ◽  
Optimum Period ◽  
Bulk Alloys

AbstractCd0.91Zn0.09Te/CdTe multilayers of various period thicknesses were inserted into Cd0.955Zn0.045Te bulk alloys grown on (001) GaAs. The net strain of the multilayer on the underlying Cd0.955Zn0.045Te was designed to be zero. X-ray diffraction full width at half maximum (FWHM) was used as a means to optimize the period thickness of the multilayer. Transmission electron microscopy of the optimum period thickness samples demonstrated four orders of magnitude decrease in the threading dislocation density. Mechanism of bending by equi-strained multilayers is discussed.

Evaluation of threading dislocation density of strained Ge epitaxial layer by high resolution x-ray diffraction

2017 ◽  
Vol 26 (12) ◽  
pp. 127309 ◽  
Author(s):  
Yuan-Hao Miao ◽  
Hui-Yong Hu ◽  
Xin Li ◽  
Jian-Jun Song ◽  
Rong-Xi Xuan ◽  
...  
Keyword(s):  
High Resolution ◽  
Dislocation Density ◽  
Epitaxial Layer ◽  
Threading Dislocation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Threading Dislocation Density

Reduction of Threading Dislocation Density in AlGaN by Indium Incorporation

2003 ◽  
Vol 798 ◽  
Author(s):  
H. Kang ◽  
Z. C. Feng ◽  
I. Ferguson ◽  
S. P. Guo ◽  
M. Pophristic
Keyword(s):  
Dislocation Density ◽  
Structural Properties ◽  
Coherence Length ◽  
Chemical Vapor ◽  
Columnar Structure ◽  
Organic Chemical ◽  
Threading Dislocation ◽  
Reciprocal Space Mapping ◽  
Threading Dislocation Density ◽  
Metal Organic

ABSTRACTThe addition of indium, even to small concentrations, to AlGaN has resulted in improved optical and doping properties for these materials. This paper is the first report of improved structural properties for indium containing AlGaN layers. A systematic series of the AlGaN layers with nominal concentration of 20% aluminum were grown by metal-organic chemical vapor deposition with traces amounts of indium incorporated into the layers (up to 0.15% indium). X-ray diffraction analysis of the layers was completed using Williamson Hall plots and reciprocal space mapping to investigate any change in the columnar structure of the initial AlGaN layers. It was found that the threading dislocation densities and lateral coherence length showed a systematic variation with indium incorporation. The threading dislocation density is lowered as indium composition increased with a corresponding increase in lateral coherence length. This indicates that even the incorporation of trace amounts of indium improves the structural properties of these epilayers.

Improved Structural Quality and Carrier Decay Times in GaN Epitaxy on SiN and TiN Porous Network Templates

2006 ◽  
Vol 527-529 ◽  
pp. 1505-1508
Author(s):  
Ümit Özgür ◽  
Y. Fu ◽  
Cole W. Litton ◽  
Y.T. Moon ◽  
F. Yun ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Structural Quality ◽  
Threading Dislocation ◽  
X Ray Diffraction ◽  
Porous Network ◽  
X Ray ◽  
Radiative Efficiency ◽  
Decay Times ◽  
Threading Dislocation Density

Improved structural quality and radiative efficiency were observed in GaN thin films grown by metalorganic chemical vapor deposition on in situ-formed SiN and TiN porous network templates. The room temperature carrier decay time of 1.86 ns measured for a TiN network sample is slightly longer than that for a 200 μm-thick high quality freestanding GaN (1.73 ns). The linewidth of the asymmetric X-Ray diffraction (XRD) (1012) peak decreases considerably with the use of SiN and TiN layers, indicating the reduction in threading dislocation density. However, no direct correlation is yet found between the decay times and the XRD linewidths, suggesting that point defect and impurity related nonradiative centers are the main parameters affecting the lifetime.

Nucleation of misfit and threading dislocations in GaSb/GaAs(001) heterostructure

1996 ◽  
Vol 54 ◽  
pp. 946-947
Author(s):  
W. Qian ◽  
M. Skowronski ◽  
R. Kaspi ◽  
M. De Graef
Keyword(s):  
Lattice Mismatch ◽  
Strain Relaxation ◽  
Threading Dislocation ◽  
Threading Dislocations ◽  
Misfit Dislocations ◽  
Extended Defects ◽  
Large Lattice ◽  
Threading Dislocation Density ◽  
Small Lattice ◽  
Large Lattice Mismatch

GaSb thin film grown on GaAs is a promising substrate for fabrication of electronic and optical devices such as infrared photodetectors. However, these two materials exhibit a 7.8% lattice constant mismatch which raises concerns about the amount of extended defects introduced during strain relaxation. It was found that, unlike small lattice mismatched systems such as InxGa1-xAs/GaAs or GexSi1-x/Si(100), the GaSb/GaAs interface consists of a quasi-periodic array of 90° misfit dislocations, and the threading dislocation density is low despite its large lattice mismatch. This paper reports on the initial stages of GaSb growth on GaAs(001) substrates by molecular beam epitaxy (MBE). In particular, we discuss the possible formation mechanism of misfit dislocations at the GaSb/GaAs(001) interface and the origin of threading dislocations in the GaSb epilayer.GaSb thin films with nominal thicknesses of 5 to 100 nm were grown on GaAs(001) by MBE at a growth rate of about 0.8 monolayers per second.

scholarly journals Effect of screw threading dislocations and inverse domain boundaries in GaN on the shape of reciprocal-space maps

2017 ◽  
Vol 50 (2) ◽  
pp. 555-560 ◽  
Author(s):  
Mykhailo Barchuk ◽  
Mykhaylo Motylenko ◽  
Gleb Lukin ◽  
Olf Pätzold ◽  
David Rafaja
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Reciprocal Space ◽  
Threading Dislocations ◽  
X Ray Diffraction ◽  
Reciprocal Space Mapping ◽  
Vapour Phase Epitaxy ◽  
X Ray ◽  
Transmission Electron ◽  
Domain Boundaries

The microstructure of polar GaN layers, grown by upgraded high-temperature vapour phase epitaxy on [001]-oriented sapphire substrates, was studied by means of high-resolution X-ray diffraction and transmission electron microscopy. Systematic differences between reciprocal-space maps measured by X-ray diffraction and those which were simulated for different densities of threading dislocations revealed that threading dislocations are not the only microstructure defect in these GaN layers. Conventional dark-field transmission electron microscopy and convergent-beam electron diffraction detected vertical inversion domains as an additional microstructure feature. On a series of polar GaN layers with different proportions of threading dislocations and inversion domain boundaries, this contribution illustrates the capability and limitations of coplanar reciprocal-space mapping by X-ray diffraction to distinguish between these microstructure features.

Sign in / Sign up

Export Citation Format

Share Document