Effect of C and Ge Concentration On The Thermal Stability of RTCVD Grown Si1-x-yGexCy Alloys

1997 ◽  
Vol 470 ◽  
Author(s):  
Patricia Warren ◽  
Stephane Retzmanick ◽  
Martin Gotza ◽  
Marc Begems
Keyword(s):  
Lattice Constant ◽  
Strain Relaxation ◽  
Mechanical Strain ◽  
Chemical Vapor ◽  
Misfit Dislocations ◽  
X Ray Diffraction ◽  
Cubic Silicon Carbide ◽  
Kinetics Of ◽  
Good Agreement

ABSTRACTSi / Si1-x-yGexCy / Si heterostructures containing up to 17 at.% Ge and 1.9 at.% C were grown on (001) silicon by low pressure Rapid Thermal Chemical Vapor Deposition, using a mixture of silane, germane and methylsilane, diluted in hydrogen. The samples were then annealed in a Rapid Thermal Processing furnace, under an atmospheric pressure of nitrogen, at temperatures ranging from 900 to 1130 °C.The samples were characterized using infrared spectroscopy and x-ray diffraction. SIMS profiling and TEM observation were performed on some of the samples.Substitutional C gradually disappeared, either precipitating out to form cubic silicon carbide (β-SiC), or simply vanishing into interstitial positions. In any case, the in-plane lattice constant remained constant after annealing, indicating that there was no mechanical strain relaxation by formation of misfit dislocations. The perpendicular lattice constant increased due to the decrease in substitutional C concentration, as well as it decreased due to the germanium out-diffusion. This variation of the strain during annealing was modeled, and allowed the determination of the kinetics of the substitutional carbon disappearance. The same behavior was observed for all samples. Indeed, the Cs disappearance rate was always increased for samples with higher initial Ge and C concentrations. The kinetics of this precipitation was found in very good agreement with previous published results.

Low Pressure MOCVD Growth and Characterization of GaAs and InP on Silicon Substrates

1988 ◽  
Vol 126 ◽  
Author(s):  
M. Razeghi ◽  
M. Defour ◽  
F. Omnes ◽  
J. Nagle ◽  
P. Maurel ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Low Pressure ◽  
Buffer Layers ◽  
Silicon Substrates ◽  
Misfit Dislocations ◽  
X Ray Diffraction ◽  
High Quality ◽  
Mocvd Growth ◽  
Vapor Deposition Technique ◽  
Low Pressure Mocvd

ABSTRACTHigh quality GaAs and InP have been grown on silicon substrates, using low pressure metalorganic chemical vapor deposition technique. The growth temperature is 550°C and the growth rate 100 A/min.Photoluminescence, X-ray diffraction and electrochemical profiling verified the high quality of these layers. The use of superlattices as buffer layers, (GaAs/GaInP) in the case of GaAs/Si and (GaInAsP/InP) in the case of InP/Si, decreased the amount of misfit dislocations in the epitaxial layer. Carrier concentrations as low as 5.1015 cm−3 have been measured by electrochemical profiling.

scholarly journals Single-sided NMR for the measurement of the degree of cross-linking and curing

2018 ◽  
Vol 7 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Norbert Halmen ◽  
Christoph Kugler ◽  
Eduard Kraus ◽  
Benjamin Baudrit ◽  
Thomas Hochrein ◽  
...  
Keyword(s):  
Relaxation Times ◽  
Curing Kinetics ◽  
Cross Linking ◽  
Scanning Calorimetry ◽  
First Results ◽  
Non Destructive ◽  
Kinetics Of ◽  
Good Agreement

Abstract. The degree of cross-linking and curing is one of the most important values concerning the quality of cross-linked polyethylene (PE-X) and the functionality of adhesives and resin-based components. Up to now, the measurement of this property has mostly been time-consuming and usually destructive. Within the shown work the feasibility of single-sided nuclear magnetic resonance (NMR) for the non-destructive determination of the degree of cross-linking and curing as process monitoring was investigated. First results indicate the possibility of distinguishing between PE-X samples with different degrees of cross-linking. The homogeneity of the samples and the curing kinetics of adhesives can also be monitored. The measurements show good agreement with reference tests (wet chemical analysis, differential scanning calorimetry, dielectric analysis). Furthermore, the influence of sample temperature on the characteristic relaxation times can be observed.

scholarly journals Analysis of oscillatory rocking curve by dynamical diffraction in protein crystals

2018 ◽  
Vol 115 (14) ◽  
pp. 3634-3639 ◽  
Author(s):  
Ryo Suzuki ◽  
Haruhiko Koizumi ◽  
Keiichi Hirano ◽  
Takashi Kumasaka ◽  
Kenichi Kojima ◽  
...  
Keyword(s):  
Glucose Isomerase ◽  
Dynamical Theory ◽  
Protein Crystals ◽  
X Ray Diffraction ◽  
High Quality ◽  
Rocking Curve ◽  
Dynamical Diffraction ◽  
High Quality Protein ◽  
Good Agreement

High-quality protein crystals meant for structural analysis by X-ray diffraction have been grown by various methods. The observation of dynamical diffraction in protein crystals is an interesting topic because dynamical diffraction generally occurs in perfect crystals such as Si crystals. However, to our knowledge, there is no report yet on protein crystals showing clear dynamical diffraction. We wonder whether the perfection of protein crystals might still be low compared with that of high-quality Si crystals. Here, we present observations of the oscillatory profile of rocking curves for protein crystals such as glucose isomerase crystals. The oscillatory profiles are in good agreement with those predicted by the dynamical theory of diffraction. We demonstrate that dynamical diffraction occurs even in protein crystals. This suggests the possibility of the use of dynamical diffraction for the determination of the structure and charge density of proteins.

Glancing Angle X-Ray Study of Crystallization of Amorphous Ge at the Ge-A1 Interface

1990 ◽  
Vol 202 ◽  
Author(s):  
S. M. Heald ◽  
J. K. D. Jayanetti ◽  
R. C. Budhani
Keyword(s):  
Initial Period ◽  
Time Characteristic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffusion Limited ◽  
Glancing Angle ◽  
Lower Temperature ◽  
Kinetics Of ◽  
Diffusion Limited Reaction ◽  
Good Agreement

ABSTRACTThe amorphous to crystalline transformation of Ge in Al/Ge thin film couples has been studied using glancing angle EXAFS, x-ray reflectivity and diffraction. It was found that crystallization occurs at a much lower temperature (118-150 °C) than for bulk Ge, and initiates at the Al/Ge interface. X-ray diffraction studies were made at 152 °C to study the kinetics of the reaction. After an initial period we find good agreement with a square root dependence of the time, characteristic of a diffusion limited reaction.

Growth of Cubic Silicon Carbide on Silicon Using Hot Filament CVD

2017 ◽  
Vol 897 ◽  
pp. 91-94
Author(s):  
Philip Hens ◽  
Ryan Brow ◽  
Hannah Robinson ◽  
Michael Cromar ◽  
Bart van Zeghbroeck
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Degrees Of Freedom ◽  
Thick Layer ◽  
Chemical Vapor ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Hot Filament ◽  
Cubic Silicon Carbide ◽  
First Time

In this paper, we report, for the first time, growth of high-quality single-crystalline 3C-SiC on silicon substrates using Hot Filament Chemical Vapor Deposition (HF-CVD). Rocking curve X-Ray diffraction (XRD) measurements revealed a full-width at half maximum (FWHM) as low as 333 arcsec for a 15 μm thick layer. Low tensile strain, below 0.1%, was measured using Raman spectroscopy. This quality was achieved with a carefully optimized process making use of the additional degrees of freedom the hot filaments create. For example, the hot filaments allow for precursor pre-cracking. Additionally, they allow a tuning of the vertical thermal gradient which creates an improved thermal field compared to classic Chemical Vapor Deposition techniques used for the deposition of this material today.

The Roles of Stress, Geometry and Orientation on Misfit Dislocations Kinetics and Energetics in Epitaxial Strained Layers.

1991 ◽  
Vol 239 ◽  
Author(s):  
R. Hull ◽  
J. C. Bean ◽  
F. Ross ◽  
D. Bahnck ◽  
L. J. Pencolas
Keyword(s):  
Misfit Dislocation ◽  
Lattice Mismatch ◽  
Strain Relaxation ◽  
Misfit Dislocations ◽  
Slip Systems ◽  
Strained Layers ◽  
Burgers Vector ◽  
Partial Dislocations ◽  
Strain Stress ◽  
Kinetics Of

ABSTRACTThe geometries, microstructures, energetics and kinetics of misfit dislocations as functions of surface orientation and the magnitude of strain/stress are investigated experimentally and theoretically. Examples are drawn from (100), (110) and (111) surfaces and from the GexSi1–x/Si and InxGa1–x/GaAs systems. It is shown that the misfit dislocation geometries and microstructures at lattice mismatch stresses < - 1GPa may in general be predicted by operation of the minimum magnitude Burgers vector slipping on the widest spaced planes. At stresses of the order several GPa, however, new dislocation systems may become operative with either modified Burgers vectors or slip systems. Dissociation of totál misfit dislocations into partial dislocations is found to play a crucial role in strain relaxation, on surfaces other than (100) under compressive stress.

Kinetics of Phosphorus Segregation in the Grain Boundaries of VVER-1000 Pressure Vessel Steels

2017 ◽  
Vol 375 ◽  
pp. 125-133 ◽  
Author(s):  
Boris Bokstein ◽  
Anatole N. Khodan ◽  
Mikhail V. Sorokin ◽  
Alexey O. Rodin ◽  
Evgeny A. Syutkin ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Auger Analysis ◽  
Phosphorus Segregation ◽  
Quantitative Measurements ◽  
Brittle Fractures ◽  
Fast Transport ◽  
Grain Bulk ◽  
Kinetics Of ◽  
Good Agreement

Methods of AES quantitative analysis were developed and applied for the determination of element concentrations at the surfaces of brittle fractures along grain boundaries. An attempt was made to take into account the presence of carbide precipitates and cleavage areas in the zone of the Auger analysis of their impact on the results of quantitative measurements. Obtained data were used for evaluation of the phosphorous segregation kinetics. The obtained results are consistent with thermodynamic modeling with CALPHAD method.Kinetics of segregation is analyzed with three models: (1) Langmuir - McLean theory; (2) model akin to kinetics of first order chemical reactions in solids; and (3) the model, which takes into account contribution of fast transport within subgrain networks and slow diffusion through the grain bulk. The two later models are in a good agreement with the experimental results.

Thermodynamics and Kinetics of Crystallization of Amorphous Si and Ge Produced by Ion Implantation

1983 ◽  
Vol 27 ◽  
Author(s):  
E.P. Donovan ◽  
F. Spaepen ◽  
D. Turnbull ◽  
J.M. Poate ◽  
D.C. Jacobson
Keyword(s):  
Noble Gas ◽  
Amorphous State ◽  
Heat Evolution ◽  
Precise Determination ◽  
Total Enthalpy ◽  
Kinetics Of Crystallization ◽  
Amorphous Si ◽  
Kinetics Of ◽  
Good Agreement

ABSTRACTAmorphous Si and Ge layers, produced by noble gas (Ar or Xe) implantation of single crystal substrates, have been crystallized in a differential scanning calorimeter (DSC). This technique allows determination of the growth velocity (which is proportional to the rate of heat evolution, ΔHac), and the total enthalpy of crystallization ΔHacAmorphous Ge was found to relax continuously to an amorphous state of lower free energy, with a total enthalpy of relaxation of 6.0 kJ.mole−1 before crystallization started. The regrowth velocity on (100) substrates,measured to be 4.2×1017 exp (−2.17eV/kT)Å/sec, is compared to other determinations. The value of ΔHac was found to be 11.66± 0.7 kJ.mole, in good agreement with ΔHac for amorphous Ge produced by other methods. For Si, ΔHac was determined to be 11.95± 0.7 kJ.mole without any evidence of heat release due to relaxation. The kinetics of crystallization measured by DSC are compared with those determined by other techniques. The effects of the implant profile on the regrowth velocity could also be observed directly in the DSC signal. The more accurate value of ΔHac allowed a more precise determination of the melting temperature of amorphous Si: Taℓ= 1420K.

Study of a chemical-vapor-deposited diamond thin film on a molybdenum substrate by glancing incidence X-ray diffraction

2007 ◽  
Vol 22 (4) ◽  
pp. 319-323 ◽  
Author(s):  
Jianfeng Fang ◽  
Jing Huo ◽  
Jinyuan Zhang ◽  
Yi Zheng
Keyword(s):  
Thin Film ◽  
Diffraction Analysis ◽  
Transition Layer ◽  
Chemical Vapor ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diamond Thin Film ◽  
Chemical Vapor Deposited

The structure of a chemical-vapor-deposited (CVD) diamond thin film on a Mo substrate was studied using quasi-parallel X-ray and glancing incidence techniques. Conventional X-ray diffraction analysis revealed that the sample consists of a diamond thin film, a Mo2C transition layer, and Mo substrate. The Mo2C transition layer was formed by a chemical reaction between the diamond film and the Mo substrate during the CVD process. A method for layer-thickness determination of the thin film and the transition layer was developed. This method was based on a relationship between X-ray diffraction intensities from the transition layer or its substrate and a function of grazing incidence angles. Results of glancing incidence X-ray diffraction analysis showed that thicknesses of the diamond thin film and the Mo2C transition layer were determined successfully with high precision.

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