Strain in Epitaxial GaAs on CaF2/Si(111)

1989 ◽  
Vol 160 ◽  
Author(s):  
L.J. Schowalter ◽  
J.E. Ayers ◽  
S.K. Ghandhi ◽  
Shin Hashimoto ◽  
W.M. Gibson ◽  
...  
Keyword(s):  
Layer Structure ◽  
High Energy ◽  
Buffer Layers ◽  
Epitaxial Layers ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
Ion Channeling ◽  
Gaas Films ◽  
Mev Protons ◽  
Good Agreement

AbstractEpitaxial layers of (111) GaAs of approximately 1 µm thickness were grown on epitaxial CaF2 buffer layers which were either 140 or 380 nm thick on Si(111) substrates. The best nucleation temperature for the GaAs on CaF2/Si(111) we have observed was 620 °C. This resulted in high quality GaAs films which exhibited channeling minimum yields of 4%. The density of threading dislocations in the GaAs layers was observed by TEM to be ~108 cm-2. Double-crystal x-ray diffraction measurements showed that the strain (ε┴.) was less than 2.2×10-4 in both sets of GaAs samples. Ion channeling, however, revealed a large tetragonal strain of 3.5×10-3 (ε┴ = 1.7×10-3) in the thinner (140 nm) CaF2 buffer layers. By doing ion channeling with high energy (2.5 MeV) protons, it was possible to determine strain more accurately. Using this technique, we were able to set an upper limit for the tetragonal strain of 2.5×10-4 in both the GaAs (which implies ε┴ < 8×10-5 and CaF2 (ε┴ < 1.5×10-4) layers for the thicker (380 nm) CaF2 buffer layer structure. These results are in good agreement with the strain predicted from previous strain measurements of CaF2 epitaxial layers on Si.

Low-Temperature Growth and Structural Characterization of GaAs Using Ionized Source Beam Epitaxy

1995 ◽  
Vol 399 ◽  
Author(s):  
D.-W. Roh ◽  
K. Kim
Keyword(s):  
Low Temperature ◽  
Film Growth ◽  
Growth Parameters ◽  
High Energy ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
Transmission Electron ◽  
Gaas Films ◽  
Substrate Temperatures ◽  
Low Temperature Grown Gaas

ABSTRACTSingle-crystal GaAs films were grown on SI (100) GaAs at substrate temperatures below 200 °C by using ionized source beam epitaxy. The correlation between the properties of the films and the growth parameters, in particular, the substrate temperature, the amount of As-source beam ionization, and the acceleration voltage of the As beam was investigated to elucidate the possible benefits of source beam ionization and acceleration on low-temperature thin film growth. The use of ionized and accelerated As-source beam greatly improved the quality of the low-temperature grown GaAs film. The surface morphology, crystallinity, and micro structure of the low temperature grown GaAs films were evaluated using in situ reflection high energy electron diffraction, double crystal X-ray diffraction, and cross section transmission electron microscopy.

Improved MOCVD Growth of GaAs on Si

1987 ◽  
Vol 91 ◽  
Author(s):  
R.M. Lum ◽  
J.K. Klingert ◽  
B.A. Davidson ◽  
M.G. Lamont
Keyword(s):  
Buffer Layer ◽  
Rutherford Backscattering Spectrometry ◽  
Growth Parameters ◽  
Buffer Layers ◽  
Double Crystal ◽  
Gaas On Si ◽  
Mocvd Growth ◽  
Gaas Films ◽  
Gaas Buffer Layer ◽  
Direct Growth

ABSTRACTIn the direct growth of GaAs on Si by MOCVD the overall quality of the heteroepitaxial film is controlled to a large extent by the growth parameters of the initial GaAs buffer layer. We have investigated the structural properties of this layer using Rutherford Backscattering Spectrometry (RBS) and X-ray double crystal diffractometry. The crystallinity of the buffer layer was observed to improve with increasing layer thickness in the range 10–100nm, and then to rapidly degrade for thicker layers. High temperature (750°C) annealing of the buffer layers resulted in considerable reordering of all but the thicker (>200 nm) layers. Alteration of the usual GaAs/Si growth sequence to include an in-situ anneal of the buffer layer after growth interruption yielded GaAs films with improved structural, optical and electrical properties.

Novel Cubic ZnxMg1−xO Epitaxial Heterostructures on Si (100) Substrates

2000 ◽  
Vol 639 ◽  
Author(s):  
A. Kvit ◽  
J. Narayan ◽  
A.K. Sharma ◽  
C. Jin ◽  
J.F. Muth ◽  
...  
Keyword(s):  
System Integration ◽  
Buffer Layers ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Lattice Matching ◽  
Lattice Constants ◽  
Ion Channeling ◽  
Microelectronic Devices ◽  
Transmission Electron ◽  
Ultraviolet Range

ABSTRACTWe have synthesized new cubic phase of ZnxMg1−xO alloy, which can be grown epitaxially on MgO (100) by lattice-matching epitaxy, and on Si (100) substrate by our domainmatching epitaxy for integration with silicon microelectronic devices. Cubic ZnxMg1−xO films on MgO (100) and Si (100) substrates were grown using a rotating target in a single chamber “insitu” pulsed-laser deposition system. Integration of ZnxMg1−xO films with silicon was accomplished via titanium nitride (TiN) buffer layers where four lattice constants of TiN match with three of the silicon during epitaxial growth via domain epitaxy. Rutherford backscattering/ion channeling techniques were used to determine chemical composition and crystalline quality of the films for x = 0.0-0.18. Detailed X-ray diffraction and transmission electron microscopy studies confirmed the epitaxial nature of ZnMgO/MgO (100) and ZnMgO/TiN/Si (100) heterostructures, and showed the formation of the Mg2−xZnxTiO4 spinel at the interface with TiN. Using optical transmission measurements, the band gap of cubic Zn0.18Mg0.82O film was estimated to be approximately 6.7 eV. The potential use of these alloys for optical devices in the ultraviolet range is discussed.

A Study of Amorphous Erbium-Based Alloys Formed by Near-Isothermal Cold-Rolling of Elemental Composites

1985 ◽  
Vol 58 ◽  
Author(s):  
Michael Atzmon ◽  
Karl M. Unruh ◽  
Constantin Politis ◽  
William L. Johnson ◽  
W. M. Keck
Keyword(s):  
Cold Rolling ◽  
Single Phase ◽  
Enthalpy Of Mixing ◽  
High Energy ◽  
Distribution Functions ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Energy Ball ◽  
Constituent Elements ◽  
Good Agreement

ABSTRACTWe report the formation of single-phase amorphous Cu-Er and Ni-Er alloys in bulk form by cold-rolling of composites prepared from elemental foils. As for previously reported cases of metallic glass formation by solid-state reaction, the driving force for the reaction is the negative enthalpy of mixing of the constituent elements. It occurs during deformation close to room temperature. Amorphous Cu7 2 Er2 8 was also produced by high-energy ball-milling of the elemental powders as well as by sputtering and liquid quenching. The alloys obtained were characterized by means of differential scanning calorimetry and x-ray diffraction. The crystallization behavior observed and the radial distribution functions obtained showed good agreement between the alloys prepared by different methods.

scholarly journals Гетероструктуры одночастотных и двухчастотных квантово-каскадных лазеров

2018 ◽  
Vol 52 (6) ◽  
pp. 597
Author(s):  
А.В. Бабичев ◽  
А.С. Курочкин ◽  
Е.С. Колодезный ◽  
А.В. Филимонов ◽  
А.А. Усикова ◽  
...  
Keyword(s):  
Quantum Cascade Laser ◽  
Quantum Cascade Lasers ◽  
Basic Structure ◽  
Epitaxial Layers ◽  
Dual Frequency ◽  
X Ray Diffraction ◽  
Quantum Cascade ◽  
High Uniformity ◽  
Cascade Lasers ◽  
Good Agreement

AbstractThe results of development of the basic structure and technological conditions of growing heterostructures for single- and dual-frequency quantum-cascade lasers are reported. The heterostructure for a dual-frequency quantum-cascade laser includes cascades emitting at wavelengths of 9.6 and 7.6 μm. On the basis of the suggested heterostructure, it is possible to develop a quantum-cascade laser operating at a difference frequency of 8 THz. The heterostructures for the quantum-cascade laser are grown using molecularbeam epitaxy. The methods of X-ray diffraction and emission electron microscopy are used to study the structural properties of the fabricated heterostructures. Good agreement between the specified and realized thicknesses of the epitaxial layers and a high uniformity of the chemical composition and thicknesses of the epitaxial layers over the area of the heterostructure is demonstrated. A stripe-structured quantum-cascade laser is fabricated; its generation at a wavelength of 9.6 μm is demonstrated.

X-Ray DCD and EPMA Measurements of Al Concentration in Epitaxial AlxGa1-xAs/GaAs Layers

1992 ◽  
Vol 36 ◽  
pp. 221-229
Author(s):  
D.A. Macquistan ◽  
I.C. Bassignana ◽  
A.J. SpringThorpe ◽  
R. Packwood ◽  
V. Moore
Keyword(s):  
Epitaxial Layers ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
X Ray ◽  
Al Content ◽  
The Relationship ◽  
Composition Measurements

AbstractDouble Crystal X-Ray Diffraction (DCD) is often used to determine the Al content of AlxGa1-xAs/GaAs epitaxial layers. Assessing composition from a measurement of mismatch is problematic because it invokes a number of assumptions. This study bypasses these difficulties by comparing the measurement of mismatch directly with Al composition measurements made by electronprobe microanalysis. A study of coherent epitaxial AlxGa1-xAs layers showed that mismatch varies linearly with composition. The equation Al (x) = |ΔΘ| / 368 summarizes the relationship over the coherent range, where |ΔΘ| is measured in arc seconds.

X-Ray Characterisation of Boron Delta Layers in Si and SiGe

1991 ◽  
Vol 220 ◽  
Author(s):  
A. R. Powell ◽  
R. A. Kubiak ◽  
T. E. Whall ◽  
E. H. C. Parker ◽  
D. K. Bowen
Keyword(s):  
High Temperature ◽  
Epitaxial Layers ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
X Ray ◽  
Carrier Confinement ◽  
Delta Layer ◽  
Non Destructive ◽  
Sheet Density

ABSTRACTWe demonstrate the growth, by MBE, of high sheet density B delta layers in both Si and SiGe epitaxial layers. Double Crystal X-Ray Diffraction is shown to be a non-destructive method of characterising the width of very narrow (0.3 nm) delta layers and the sheet density of the activated B. The ability of delta layers to withstand high temperature anneals is considered and it is found that a 750 °C anneal for 1 hour broadens the delta layer to beyond the width required for carrier confinement.

High-energy double-crystal X-ray diffraction

1988 ◽  
Vol 21 (5) ◽  
pp. 516-520 ◽  
Author(s):  
V. Holý ◽  
S. Cummings ◽  
M. Hart
Keyword(s):  
High Energy ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
X Ray

Grain Rotation during Twin-Detwin Deformation of Mg AZ31 Alloy Using In Situ XRD and EBSD

2019 ◽  
Vol 793 ◽  
pp. 17-22
Author(s):  
Hong Jia Zhang ◽  
Enrico Salvati ◽  
Chrysanthi Papadaki ◽  
Kai Soon Fong ◽  
Xu Song ◽  
...  
Keyword(s):  
Electron Backscatter Diffraction ◽  
Az31 Alloy ◽  
High Energy ◽  
Intensity Change ◽  
X Ray Diffraction ◽  
Grain Rotation ◽  
Backscatter Diffraction ◽  
Tension Loading ◽  
Good Agreement

To investigate grain rotation caused by twinning-detwinning during plastic deformation, experiments using synchrotron high energy X-ray Diffraction (XRD) and Electron Backscatter Diffraction (EBSD) are carried out under in situ compression-tension loading. Comparison between the XRD and EBSD data confirms that the intensity change of diffraction rings in XRD experiment is caused by twining and detwinning. A good agreement of twin fraction values obtained from XRD and EBSD is achieved. This demonstrates that the grains and texture are homogeneously distributed along the normal direction of the sample. In the meantime, it is observed that detwinning can only be activated in a large quantity when the loading reverses into tension from compression in the first loading stage.

scholarly journals Structures and Spectroscopy Studies of Two M(II)-Phosphonate Coordination Polymers Based on Alkaline Earth Metals (M = Ba, Mg)

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Kui-Rong Ma ◽  
Chun-Li Wei ◽  
Yu Zhang ◽  
Yu-He Kan ◽  
Ming-Hui Cong ◽  
...  
Keyword(s):  
Coordination Polymers ◽  
Alkaline Earth ◽  
Layer Structure ◽  
High Energy ◽  
Triangular Prism ◽  
X Ray Diffraction ◽  
Coordination Effect ◽  
Ft Ir ◽  
Energy Emissions ◽  
Spectroscopy Studies

The two examples of alkaline-earth M(II)-phosphonate coordination polymers, [Ba2(L)(H2O)9]·3H2O (1) and [Mg1.5(H2O)9]·(L-H2)1.5·6H2O (2) (H4L = H2O3PCH2N(C4H8)NCH2PO3H2),N,N′-piperazinebis(methylenephosphonic acid), (L-H2= O3PH2CHN(C4H8)NHCH2PO3) have been hydrothermally synthesized and characterized by elemental analysis, FT-IR, PXRD, TG-DSC, and single-crystal X-ray diffraction. Compound1possesses a 2D inorganic-organic alternate arrangement layer structure built from 1D inorganic chains through the piperazine bridge, in which the ligand L−4shows two types of coordination modes reported rarely at the same time. In1, both crystallographic distinct Ba(1) and Ba(2) ions adopt 8-coordination two caps and 9-coordination three caps triangular prism geometry structures, respectively. Compound2possesses a zero-dimensional mononuclear structure with two crystallographic distinct Mg(II) ions. Free metal cations  [MgO6]n2+and uncoordinated anions(L-H2)n2-are joined together by static electric force. Results of photoluminescent measurement indicate three main emission bands centered at 300 nm, 378.5 nm, and 433 nm for1and 302 nm, 378 nm, and 434.5 nm for2(λex=235 nm), respectively. The high energy emissions could be derived from the intraligandπ∗-ntransition stations ofH4L(310 nm and 382 nm,λex=235 nm), while the low energy emission (>400 nm) of1-2may be due to the coordination effect with metal(II) ions.

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