X-ray characterization of defect structure in LEC GaAs crystals

1991 ◽  
Vol 108 (3-4) ◽  
pp. 744-750 ◽  
Author(s):  
G. Kowalski ◽  
E. Zielinska-Rohozinska ◽  
T. Czekalski
Keyword(s):  
Defect Structure ◽  
X Ray ◽  
Lec Gaas

SEM Characterization of Silicon Layers Grown on Carbon Foil

2009 ◽  
Vol 156-158 ◽  
pp. 473-476 ◽  
Author(s):  
Sergei K. Brantov ◽  
A.V. Eltzov ◽  
Olga V. Feklisova ◽  
Eugene B. Yakimov
Keyword(s):  
Dislocation Density ◽  
Defect Structure ◽  
Growth Direction ◽  
Carbon Foil ◽  
Twin Boundaries ◽  
X Ray ◽  
Electron Backscattering Diffraction ◽  
Silicon Ribbon ◽  
Selective Chemical

Characterization of defect structure in silicon ribbon grown on carbon foil has been carried out. The structure of grown Si layers and a dislocation density in these layers have been studied using selective chemical etching and the Electron Backscattering Diffraction. It is observed that the layers consist of rather large grains, the majority of which is elongated along the growth direction with a similar surface orientation and with a misorientation angle between neighboring grains of 60º. This means that such grains are separated by the (111) twin boundaries. The dislocation density in different grains is found to vary from 102 to 107cm-2. The energy dispersive X-Ray microanalysis has shown that some twin boundaries are enriched with carbon.

Structural Characterization of the Growth Front of 4H-SiC Boules Grown Using the Physical Vapor Transport Growth Method

2018 ◽  
Vol 924 ◽  
pp. 15-18
Author(s):  
Masashi Sonoda ◽  
Kentaro Shioura ◽  
Takahiro Nakano ◽  
Noboru Ohtani ◽  
Masakazu Katsuno ◽  
...  
Keyword(s):  
High Resolution ◽  
Surface Morphology ◽  
Defect Structure ◽  
Growth Front ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
X Ray Diffraction ◽  
X Ray ◽  
Growth Method

The defect structure at the growth front of 4H-SiC boules grown using the physical vapor transport (PVT) method has been investigated using high resolution x-ray diffraction and x-ray topography. The crystal parameters such as the c-lattice constant exhibited characteristic variations across the growth front, which appeared to be caused by variation in surface morphology of the as-grown surface of the boules rather than the defect structure underneath the surface. X-ray topography also revealed that basal plane dislocations are hardly nucleated at the growth front during PVT growth of 4H-SiC crystals.

GROWTH AND SPECTROSCOPIC CHARACTERIZATION OF Mg:Ce:Cu:LiNbO3 CRYSTALS

2008 ◽  
Vol 22 (15) ◽  
pp. 1487-1495 ◽  
Author(s):  
YEXIA FAN ◽  
HONGTAO LI ◽  
LIANCHENG ZHAO
Keyword(s):  
Mass Spectrometry ◽  
Defect Structure ◽  
Inductively Coupled Plasma ◽  
Optical Emission ◽  
Spectroscopic Characterization ◽  
Threshold Concentration ◽  
Ir Absorption ◽  
X Ray ◽  
Inductively Coupled

Congruent Ce (0.1 wt %): Cu (0.05 wt %): LiNbO 3 single crystals doped with 0, 1, 3, 4, 5, 6 mol% MgO respectively were grown by the Czochrolski method in air along the C direction. The inductively coupled plasma optical emission/mass spectrometry (ICP-OE/MS), the X-ray powder diffraction (XRD), the differential thermal analysis (DTA), the ultraviolet-visible (UV-Vis) absorption spectra and the infrared (IR) absorption spectrum were measured and discussed in terms of the spectroscopic characterization and the defect structure of the Mg:Ce:Cu:LiNbO 3 crystals. The results indicated that the Mg:Ce:Cu:LiNbO 3 crystal grown from the congruent composition melt showed large [ Li ]/[ Nb ] ratios, which was closer to stoichiometry, an increase in the Curie temperature and a non-linear shift in the absorption edge with MgO concentration increasing. The threshold concentration of MgO in Mg:Ce:Cu:LiNbO 3 of nearly 5.52 mol% was estimated.

Microstructural Characterization of GaAs Substrates

1986 ◽  
Vol 69 ◽  
Author(s):  
T. M. Moore ◽  
S. Matteso ◽  
W. M. Duncan ◽  
R. J. Matyi
Keyword(s):  
Defect Structure ◽  
Microstructural Characterization ◽  
Acoustic Microscopy ◽  
Double Crystal ◽  
X Ray ◽  
Major Transitions ◽  
Gaas Substrates ◽  
Defect Microstructures ◽  
Electron Acoustic

AbstractThe defect microstructures of GaAs substrates have been investigated in a multi-technique approach including integral cathodoluminescence (CL), scanning electron acoustic microscopy (SEAM), double crystal x-ray topography (XRT), and defect delineation etch. The XRT, CL, and SEAM studies are of identical areas on <100> SI GaAs(Cr) grown by the liquid encapsulated Czochralski (LEC) method and by the horizontal Bridgman (HB) method. Correlation was made to the defect structure revealed by defect delineation etching. The samples were also characterized by Fourier transform photoluminescence (FTPL) to qualitatively identify the major transitions contributing to the CL images. The CL, SEAM, XRT, and defect delineation etch images of each material are compared and their different perspectives are discussed.

An expert system for the structural characterization of kaolinites

Clay Minerals ◽  
1990 ◽  
Vol 25 (3) ◽  
pp. 249-260 ◽  
Author(s):  
A. Plançon ◽  
C. Zacharie
Keyword(s):  
Expert System ◽  
Defect Structure ◽  
Defect Structures ◽  
X Ray Diffraction ◽  
Diffraction Profile ◽  
X Ray ◽  
Diffraction Patterns ◽  
Xrd Patterns

AbstractUntil recently, the determination of the defect structures (previously referred to incorrectly as “crystallinity”) of kaolinites has been obtained in one of two ways: (1) measurement of the Hinckley index, or (2) by comparing calculated X-ray diffraction patterns based on a model of the defect structure (including types of defects and abundances) with experimental diffraction profiles. The Hinckley method is simple and easy to perform but contains no real information about the defect structure. Calculated XRD patterns are based on real defects but these calculations are time consuming and require some skill in application. Another approach is proposed: an expert system which will accurately describe the defect structure of kaolinites based on a few measurements taken from a normal powder diffraction profile. This system has been verified for nine kaolinite samples for which the defect structure was previously determined by comparison of calculated and observed diffraction profiles. The expert system reproduced the correct defect structure for each of the samples.

Investigation of the Homogeneity and Defect Structure in Semi-Insulating Lec GaAs Single Crystals by Synchrotron Radiation Double Crystal X-Ray Topography.

1984 ◽  
Vol 41 ◽  
Author(s):  
S J Barnett ◽  
B K Tanner ◽  
G. T. Brown
Keyword(s):  
Synchrotron Radiation ◽  
Single Crystals ◽  
Defect Structure ◽  
Deep Level ◽  
Lattice Parameter ◽  
Double Crystal ◽  
X Ray ◽  
Lec Gaas ◽  
Order Of Magnitude ◽  
Small Lattice

AbstractThe high intensity and large beam size of a synchrotron radiation source have been exploited in order to obtain double crystal X-ray topographs of whole 2in. and 3in. slices of semi-insulating LEC GaAs single crystals. Exposure times, typically 30 minutes for high resolution topographs, are at least one order of magnitude down on those required when using a conventional source. Variations in relative lattice parameter and lattice tilt have been measured as a function of position on the slice. The defect structure has been imaged and dislocations are seen in cellular configurations, slip bands and linear arrays (lineage), the latter of which are shown to be associated with small lattice tilts, typically 30”. The defect structure revealed on the topographs has been correlated with 1μm infrared absorption micrographs which are believed to represent the concentration of the dominant deep level EL2.

X-ray Characterization of Defect Structure in LEC Annealed GaAs Crystals

1992 ◽  
Vol 27 (7) ◽  
pp. 947-951
Author(s):  
T. Czekalski ◽  
E. Zielińska-Rohozińska
Keyword(s):  
Defect Structure ◽  
X Ray

TEM characterization of CMR thin film on [001] SrTiO3 substrate

1996 ◽  
Vol 54 ◽  
pp. 630-631
Author(s):  
Y.Y. Wang ◽  
A. Gupta ◽  
V.P. Dravid
Keyword(s):  
Thin Film ◽  
Defect Structure ◽  
Bulk Material ◽  
X Ray Diffraction ◽  
Magnetic Device ◽  
X Ray ◽  
Jahn Teller ◽  
Cubic Structure ◽  
Base Structure

Due to its potential magnetic device application, giant/colossal magnetoresistant (GMR or CMR) material, (bulk material as well as thin film), have been under intense investigation in recent years. In the bulk material, the changes of the resistivity under 4T magnetic field is about 80% at the metal-insulate transition temperature for La0.7Ca0.3MnO3 (LCMO). In 1994, S. Jin et al reported thousandfold change in resistivity in magnetoresistive La-Ca-Mn-0 films on a LaAlO3 substrate. It is suspected that such a large magnetoresistivity change in the thin film is due to the defect structure in the epitaxially grown thin film.The base structure of LCMO is an MnO6 octahedral perovskite cubic structure. Because of its strong static Jahn-Teller (JT) distortion, the compound is metrically orthorhombic, with a∼b∼√2 ap and c∼2ap where ap is the lattice constant for the base cubic structure. X-ray diffraction study on this compound shows that it belongs to Pnma space group.

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