Bulk Growth of SiC

2008 ◽  
Vol 1069 ◽  
Author(s):  
Peter Wellmann ◽  
Ralf P. Müller ◽  
Sakwe A. Sakwe ◽  
Ulrike Künecke ◽  
Philip Hens ◽  
...  
Keyword(s):  
Dislocation Density ◽  
X Rays ◽  
Dislocation Generation ◽  
Thermally Induced ◽  
Bulk Crystal Growth ◽  
Bulk Growth ◽  
Single Defect ◽  
Process Visualization ◽  
Continuous Feeding

ABSTRACTThe paper reviews the basics of SiC bulk growth by the physical vapor transport (PVT) method and discuss current and possible future concepts to improve crystalline quality. In-situ process visualization using x-rays, numerical modeling and advanced doping techniques will be briefly presented which support growth process optimization. The “pure” PVT technique will be compared with related developments like the so called Modified-PVT, Continuous-Feeding-PVT, High-Temperature-CVD and Halide-CVD concepts. Special emphasis will be put on dislocation generation and annihilation and concepts to reduce dislocation density during SiC bulk crystal growth. The dislocation study is based on a statistical approach. Rather than following the evolu-tion of a single defect, statistic data which reflect a more global dislocation density evolution are interpreted. In this context a new approach will be presented which relates thermally induced strain during growth and dislocation patterning in networks.

Observation of Lattice Plane Bending during SiC PVT Bulk Growth Using In Situ High Energy X-Ray Diffraction

2010 ◽  
Vol 645-648 ◽  
pp. 29-32 ◽  
Author(s):  
Rainer Hock ◽  
Katja Konias ◽  
L. Perdicaro ◽  
Andreas Magerl ◽  
Philip Hens ◽  
...  
Keyword(s):  
Growth Process ◽  
Growth Front ◽  
High Energy ◽  
Lattice Plane ◽  
X Ray Diffraction ◽  
Thermally Induced ◽  
X Ray ◽  
Bulk Growth ◽  
Plane Bending

We have investigated thermally induced strain in the SiC crystal lattice during physical vapor transport bulk growth. Using high energy x-ray diffraction lattice plane bending was observed in-situ during growth. With increasing growth rate increasing lattice plane bending and, hence, strain was observed. A comparison with numerical modeling of the growth process shows that the latter is related to the heat of crystallization which needs to be dissipated from the crystal growth front. The related temperature gradient as driving force for the dissipation of the heat of crystallization causes lattice plane bending. Optimization of the growth process needs to consider such effects.

DIFFRACTION ANALYSIS OF DEFORMED METALS: Theory, Methods, Programs

2019 ◽  
Author(s):  
Faina Satdarova
Keyword(s):  
Experimental Design ◽  
Dislocation Density ◽  
Mathematical Models ◽  
Diffraction Analysis ◽  
Experimental Research ◽  
Russian Federation ◽  
Statistical Estimation ◽  
X Rays ◽  
National University ◽  
The Russian Federation

General analysis of the distribution of crystals orientation and dislocation density in the polycrystalline system is presented. Recovered information in diffraction of X-rays adopting is new to structure states of polycrystal. Shear phase transformations in metals — at the macroscopic and microscopic levels — become a clear process. Visualizing the advances is produced by program included in package delivered. Mathematical models developing, experimental design, optimal statistical estimation, simulation the system under study and evolution process on loading serves as instrumentation. To reduce advanced methods to research and studies problem-oriented software will promote when installed. Automation programs passed a testing in the National University of Science and Technology “MISIS” (The Russian Federation, Moscow). You score an advantage in theoretical and experimental research in the field of physics of metals.

scholarly journals Thermally-induced hyperbranching of bromine-containing polyesters by insertion of in situ generated chain-end carbenes

2021 ◽  
Author(s):  
Panos Bexis ◽  
Craig Bell ◽  
Maria Chiara Arno ◽  
Anthony Thomas ◽  
Andrew P Dove
Keyword(s):  
Thermally Induced ◽  
End Group

Hyperbranched, biodegradable PCL-based polymers are obtained through a random but invasive migration of an in-situ generated carbene end group which is unmasked via the thermolysis of its precursor diazirine moiety....

In Situ Testing and X Rays Radiation Effects of Pt/Bi3.15Nd0.85Ti3O12/Pt Ferroelectric Capacitors

2013 ◽  
Vol 712-715 ◽  
pp. 293-297
Author(s):  
Li Li
Keyword(s):  
Radiation Effects ◽  
Hysteresis Loops ◽  
Electrical Performance ◽  
Hysteresis Curve ◽  
X Rays ◽  
Shanghai Synchrotron Radiation Facility ◽  
X Ray ◽  
In The Beginning ◽  
Ferroelectric Capacitors

Pt/Bi3.15Nd0.85Ti3O12(BNT)/Pt ferroelectric capacitors were monitored using in situ X-ray irradiation with 10 keV at BL14B1 beamline (Shanghai Synchrotron Radiation Facility). BL14B1 combined with a ferroelectric analyzer enabled measurements in situ of electrical performance. The hysteresis curve (PE) of distortion depended on the polarization during irradiation, but the diffracted intensities of the (117) peak did not change in the beginning. ThePEcurve had a negligible change from 2.09×109Gy to 4.45×109Gy. Finally, bothPrandPr+very rapidly increased, but the intensities of (117) decreased. The hysteresis loops were remarkably deformed at the maximum total dose of 4.87×109Gy.

Applications of High-Resolution Powder X-Ray Diffraction

2007 ◽  
Vol 130 ◽  
pp. 7-14 ◽  
Author(s):  
Andrew N. Fitch
Keyword(s):  
High Resolution ◽  
Synchrotron Radiation ◽  
Powder Diffraction ◽  
X Rays ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Structural Characterisation ◽  
Pdf Analysis

The highly-collimated, intense X-rays produced by a synchrotron radiation source can be harnessed to build high-resolution powder diffraction instruments with a wide variety of applications. The general advantages of using synchrotron radiation for powder diffraction are discussed and illustrated with reference to the structural characterisation of crystalline materials, atomic PDF analysis, in-situ and high-throughput studies where the structure is evolving between successive scans, and the measurement of residual strain in engineering components.

Paleopathological study of the Egyptian mummies collected in Italy: the Anubis project

1970 ◽  
Vol 80 (1) ◽  
Author(s):  
Rosalba Ciranni ◽  
Donata Pangoli ◽  
Valentina Giuffra ◽  
DAvide Caramella ◽  
Edda Bresciani ◽  
...  
Keyword(s):  
X Rays ◽  
Axial Tomography ◽  
Technical Problems ◽  
Histological Studies ◽  
Computed Axial Tomography ◽  
The University ◽  
First Time

Eighty-five Egyptian mummies belonging to different dynastic periods and collected in a number of Italian museums, have been censed and submitted for paleopathological research. In most cases the presence of bandages required the application of X- rays and computed axial tomography (CAT). Fifty-two mummies have been studied in situ with Xrays; twelve with CAT scanning. Technical problems kept us from investigating eleven of the censed mummies. In a few cases it was possible to perform autopsies, endoscopy, or histological studies. The mummies submitted for X- rays were divided into two groups: The first group thirty-six mummies studied by the team of Paleopathology-Egyptology of the University of Pisa were studied for the first time. The second group was composed of twenty-six mummies studied elsewhere in Italy. Those results also have been included in the Anubi Project database.

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