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.

Grazing Incidence X-ray Topographic Studies of Threading Dislocations in Hydrothermal Grown ZnO Single Crystal Substrates

2013 ◽  
Vol 1494 ◽  
pp. 121-126 ◽  
Author(s):  
Tianyi Zhou ◽  
Balaji Raghothamachar ◽  
Fangzhen Wu ◽  
Michael Dudley
Keyword(s):  
Single Crystal ◽  
Grazing Incidence ◽  
Threading Dislocation ◽  
Threading Dislocations ◽  
Screw Dislocations ◽  
X Ray ◽  
Dislocation Defects ◽  
Image Position ◽  
Threading Defects ◽  
Zno Single Crystal

ABSTRACTZnO single crystal substrates grown by the hydrothermal method have been characterized by grazing incidence X-ray topography using both monochromaticand whitesynchrotron X ray beams.11$\bar 2$4 reflection wasrecorded from the (0001) wafers and the different contrast patterns produced by different threading defects were noted. To uniquely identify the Burgers vectors of these threading dislocation defects, we use raytracingsimulation to compare with observed defect contrast. Our studies showed that threading screw dislocations are not commonly observed.Most threading edge dislocationshavetheBurgers vector of1⁄3[2$\bar 1$$\bar 1$0] or1⁄3[12$\bar 2$10]and a density of 2.88×104/cm2.

Growth of Improved GaAs/Si: Suppression of Volmer-Weber Nucleation for Reduced Threading Dislocation Density

1998 ◽  
Vol 535 ◽  
Author(s):  
P. J. Taylor ◽  
W.A. Jesser ◽  
G. Simonis ◽  
W. Chang ◽  
M. Lara-Taysing ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Single Crystal ◽  
Threading Dislocation ◽  
Full Width ◽  
Half Maximum ◽  
Growth Technique ◽  
X Ray ◽  
Threading Dislocation Density ◽  
Island Coalescence ◽  
Initial Deposition

AbstractThe growth of reduced dislocation density GaAs/Si is performed by a novel two-step technique where the first epitaxy step takes place at 75° C and the second is performed at 580° C. The initial deposition is single crystal, continuous, and planar such that there is no contribution to the dislocation density from Volmer-Weber island coalescence and no trapping of dislocations in pinholes. Using this new growth technique, a reduced dislocation density the order of 106/cm2 was obtained. The improved crystallinity is indicated by the more narrow x-ray full-width-at-half-maximum (FWHM) value of 110 arcseconds. GaAs p-i-n diodes were grown on the reduced dislocation density GaAs/Si and it was found that the resistivity of the intrinsic region for the heteroepitaxial diodes was similar to homoepitaxial ones for small mesa sizes.

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.

TEM characterization of dislocation reduction processes in GaAs/Si

1989 ◽  
Vol 47 ◽  
pp. 590-591
Author(s):  
R.A. Herring ◽  
P.N. Uppal ◽  
S.P. Svensson ◽  
J.S. Ahearn
Keyword(s):  
Lattice Mismatch ◽  
Threading Dislocation ◽  
Threading Dislocations ◽  
Growth Interface ◽  
Dislocation Reduction ◽  
Dislocation Densities ◽  
Threading Dislocation Density ◽  
Interfacial Dislocations ◽  
Strained Layer Superlattices

A high density of interfacial dislocations are needed at the GaAs/Si interface to alleviate the 4% lattice mismatch between GaAs and Si. Some remnant dislocations thread through the epilayer and follow the growth interface. Current growth methods are not able to obtain acceptable threading dislocation densities (104 – 105) for devices. Many methods can be used to reduce the number of threading dislocations which include misorienting the substrate to enhance the slip of dislocations on specific [110]{111} planes, annealing during and after growth, and adding strained layer superlattices (SLS's) to block dislocations. Conventional TEM (CTEM), performed using a JEM 100c, has been used to characterize threading dislocations in the epilayer of a GaAs/Si material where in situ thermal annealing and SLS's force dislocation reactions and thereby reduce the threading dislocation density. Using TEM we have viewed dislocations under many two-beam diffraction conditions and with the help of a stereogram have determined their Burgers vectors (b), line directions (u) and habit planes (R).

Dislocation Distributions in Cd1-xHgxTe/CdTe and Cd1-xHgxTe/Cd1-yZnyTe Grown by Liquid Phase Epitaxy

1994 ◽  
Vol 356 ◽  
Author(s):  
C. C. R. Watson ◽  
K. Durose ◽  
E. O’Keefe ◽  
J. M. Hudson ◽  
B. K. Tanner
Keyword(s):  
Liquid Phase ◽  
Dislocation Density ◽  
Liquid Phase Epitaxy ◽  
Threading Dislocation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dislocation Densities ◽  
Threading Dislocation Density ◽  
O 24

Epilayers of LPE Cdo.24Hgo.76Te grown on (111)B CdTe and Cdi-xZnxTe substrates have been examined by defect etching and triple axis x-ray diffraction. Defect etching of bevelled layers has shown the threading dislocation density to fall with increasing distance from the heterointerface, for distances <6μm. In thicker regions however a constant ‘background’ dislocation density is observed. Background dislocation densities of ∼ 3 x 105cm-2 and 9 x 104cm-2 have been measured for layers grown on CdTe and Cdo.96Zn0.04Te respectively, this is compared with a substrate dislocation density of ∼ 3 x 104cm-2 measured in both types of substrates. The increase in the dislocation density within the epilayers compared with the corresponding substrate is discussed. An explanation is also given for the displacement of the peak dislocation density, from the interface to within the layer, observed in the Cd0.76Hg0.24Te / Cd0.96Zn0.04Te system.

High-Speed Growth of 4H-SiC Single Crystal Using Si-Cr Based Melt

2013 ◽  
Vol 740-742 ◽  
pp. 73-76 ◽  
Author(s):  
Motohisa Kado ◽  
Hironori Daikoku ◽  
Hidemitsu Sakamoto ◽  
Hiroshi Suzuki ◽  
Takeshi Bessho ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Single Crystal ◽  
High Speed ◽  
High Rate ◽  
Threading Dislocation ◽  
High Quality ◽  
X Ray ◽  
Interface Kinetics ◽  
Threading Dislocation Density ◽  
Rate Limiting

In this study, we have investigated the rate-limiting process of 4H-SiC solution growth using Si-Cr based melt, and have tried high-speed growth. It is revealed that the rate-limiting process of SiC growth under our experimental condition is interface kinetics, which can be controlled by such factors as temperature and supersaturation of carbon. By enhancing the interface kinetics, SiC crystal has been grown at a high rate of 2 mm/h. The FWHM values of X-ray rocking curves and threading dislocation density of the grown crystals are almost the same as those of seed crystal. Possibility of high-speed and high-quality growth of 4H-SiC has been indicated.

scholarly journals Specular reflection intensity modulated by grazing-incidence diffraction in a wide angular range

2018 ◽  
Vol 74 (5) ◽  
pp. 545-552
Author(s):  
K. V. Nikolaev ◽  
I. A. Makhotkin ◽  
S. N. Yakunin ◽  
R. W. E. van de Kruijs ◽  
M. A. Chuev ◽  
...  
Keyword(s):  
Single Crystal ◽  
Specular Reflection ◽  
Subsurface Layer ◽  
Grazing Incidence ◽  
Matrix Formalism ◽  
Angular Range ◽  
Subsurface Structure ◽  
X Ray ◽  
Reflection Intensity

Grazing-incidence X-ray diffraction (GID) is a well known technique for the characterization of crystal surfaces. A theoretical study has been performed of the sensitivity of GID to the structure of a crystal surface and distorted nanometre-thin surface layers. To simulate GID from crystals that have a complex subsurface structure, a matrix formalism of the dynamical diffraction theory has been applied. It has been found that the azimuthal rocking curves of a crystal that has a distorted subsurface, measured over a wide angular range, show asymmetric thickness oscillations with two distinguishable sets of frequencies: one corresponding to the diffraction in the single-crystal subsurface layer and the second corresponding to the diffraction in the single-crystal substrate. Therefore, azimuthal rocking curves allow characterization of the subsurface structure of a single crystal. Furthermore, thickness oscillations induced by evanescent diffraction modulate the specular reflection intensity, showing high-intensity modulations. This will potentially allow implementation of subsurface crystal characterization using, for instance, a laboratory-scale X-ray diffractometer.

Reference-free, depth-dependent characterization of nanolayers and gradient systems with advanced grazing incidence X-ray fluorescence analysis

2015 ◽  
Vol 212 (3) ◽  
pp. 523-528 ◽  
Author(s):  
Philipp Hönicke ◽  
Blanka Detlefs ◽  
Matthias Müller ◽  
Erik Darlatt ◽  
Emmanuel Nolot ◽  
...  
Keyword(s):  
Fluorescence Analysis ◽  
Grazing Incidence ◽  
X Ray ◽  
Gradient Systems

Defect-Engineered Graded GexSi1-x Buffers on Si (001) with Extreme Low Threading Dislocation Density

1995 ◽  
Vol 378 ◽  
Author(s):  
G. Kissinger ◽  
T. Morgenstern ◽  
G. Morgenstern ◽  
H. B. Erzgräber ◽  
H. Richter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Dislocation Density ◽  
Threading Dislocation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Threading Dislocation Density

AbstractStepwise equilibrated graded GexSii-x (x≤0.2) buffers with threading dislocation densities between 102 and 103 cm−2 on the whole area of 4 inch silicon wafers were grown and studied by transmission electron microscopy, defect etching, atomic force microscopy and photoluminescence spectroscopy.

Sign in / Sign up

Export Citation Format

Share Document