Strain Measurements in Si/Si0.5Ge0.5 Superlattices by He Ion Channeling

1987 ◽  
Vol 91 ◽  
Author(s):  
S. Mantl ◽  
E. Kasper ◽  
H. J. Jorke
Keyword(s):  
Buffer Layer ◽  
Elastic Energy ◽  
Molecular Beam ◽  
Stable Structure ◽  
Strain Fields ◽  
Strain Measurements ◽  
Ion Channeling

ABSTRACTHe ion channeling experiments have been performed on molecular beam grown Si/SiGe superlattices to determine the strain fields. Angular yield scans provide directly the tetragonal strains in the layers. In Si/Si0.5Ge0.5 superlattices grown on (100) Si only the SiGe layers are strained. Almost equal but opposite strains in the Si and SiGe layers have been found in a Si/Si0.5Ge0.5 superlattice deposited on a 230 nm thick SiO.71Ge0.29 buffer layer. Strain symmetrization yields the minimum elastic energy and thus to the most stable structure.

Strain Measurements of Sigec Heteroepitaxial Layers On Si(100) Using Ion Beam Analysis

1994 ◽  
Vol 354 ◽  
Author(s):  
S. Sego ◽  
R. J. Culbertson ◽  
P. Ye ◽  
S. Hearne ◽  
J. Xiang ◽  
...  
Keyword(s):  
Molecular Beam ◽  
Rutherford Backscattering Spectrometry ◽  
Ion Beam ◽  
Chemical Vapor ◽  
Major Axis ◽  
Ion Scattering ◽  
Strain Measurements ◽  
Ion Channeling ◽  
Beam Analysis ◽  
Heteroepitaxial Layers

AbstractThe strain in SiGeC heteroepitaxial films grown on Si(100) substrates has been quantified using ion channeling. The films were grown both by combined ion beam and molecular beam epitaxy (CIMD) and chemical vapor deposition (CVD). Rutherford backscattering spectrometry (RBS) was used to quantify the Ge concentration as well as the film thickness, nuclear resonance elastic ion scattering was used to quantify the carbon concentration, and ion channeling was utilized to measure film quality. Channeling angular scans across an off normal major axis were used to quantify the strain. Part of the film was removed by using a solution of HF, HN03 and CH3COOH in order to obtain a reliable scan in the substrate. The results indicate that C may be compensating for the strain introduced by Ge.

Strain in Epitaxial GaAs on Si and CaF2/Si

1987 ◽  
Vol 102 ◽  
Author(s):  
L. J. Schowalter ◽  
Shin Hashimoto ◽  
G. A. Smith ◽  
W. M. Gibson ◽  
N. Lewis ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Gaas Layer ◽  
Buffer Layers ◽  
Threading Dislocations ◽  
Si Substrate ◽  
High Quality ◽  
Strain Measurements ◽  
Epitaxial Gaas ◽  
Ion Channeling ◽  
Gaas On Si

ABSTRACTIn this paper, ion channeling techniques are used to show that epitaxial GaAs layers grown on vicinal Si(001) wafers do not have their [001] axis precisely aligned with that of the Si substrate. Instead, the [001] axis of the GaAs layer is found to be tilted toward the surface normal of the Si substrate. This tilt was found to be ∼0.2° on vicinal Si(001) substrates which have their [001] axis tilted 4° toward the [110] azimuth. It is speculated that this misalignment is reponsible for the residual density of threading dislocations in the GaAs on Si layer. An approach described here, which can be used to avoid strain in the GaAs layer, is to grow a CaF2 buffer layer between the Si substrate and the epitaxial GaAs layer. High quality epitaxial GaAs layers have been obtained on both CaF 2 /Si(001) and CaF 2 /Si(111) substrates. Strain measurements of the epitaxial GaAs on the CaF 2 buffer layers indicate that these layers have strains below our detection limits.

Photoluminescence Characterization of Heteroepitaxial ZnSe/GaAs and ZnSe/AlAs Grown By MBE

1987 ◽  
Vol 102 ◽  
Author(s):  
B. J. Skromme ◽  
M. C. Tamargo ◽  
J. L. De Miguel ◽  
R. E. Nahory
Keyword(s):  
Buffer Layer ◽  
Molecular Beam ◽  
Crystal Defects ◽  
Buffer Layers ◽  
Acceptor Pair ◽  
Strain Fields ◽  
Donor Acceptor ◽  
Tentative Explanation ◽  
Donor Acceptor Pair

ABSTRACTHeteroepitaxial ZnSe grown by molecular beam epitaxy (MBE) has been characterized using low temperature photoluminescence (PL) and reflectance. Excitonic PL linewidths of thick (relaxed) ZnSe layers are>1.4 meV, and depend little on the type of substrate or buffer layer used (e.g. GaAs or AlAs). In contrast, thin (pseudomorphic) ZnSe layers on AlAs buffer layers of moderate thickness are found to exhibit by far the sharpest (FWHM=0.22-0.37 meV) excitonic features ever observed for heteroepitaxial ZnSe grown by any technique. A tentative explanation for this result is that step-grading the lattice constant (by the AlAs buffer layer) has eliminated the crystal defects which produce localized strain fields that inhomogeneously broaden the peaks in ZnSe/GaAs. Acceptor-related PL peaks are discussed, and the first discrete donor-acceptor pair line spectrum in heteroepitaxial ZnSe is reported.

scholarly journals Investigation of GaAs surface treatments for ZnSe growth by molecular beam epitaxy without a buffer layer

2021 ◽  
Vol 549 ◽  
pp. 149245
Author(s):  
Chaomin Zhang ◽  
Kirstin Alberi ◽  
Christiana Honsberg ◽  
Kwangwook Park
Keyword(s):  
Molecular Beam Epitaxy ◽  
Buffer Layer ◽  
Molecular Beam ◽  
Surface Treatments ◽  
Gaas Surface

Metalorganic Molecular Beam Epitaxy of GaAsP for Visible Light-Emitting Devices on Si

1998 ◽  
Vol 535 ◽  
Author(s):  
M. Yoshimoto ◽  
J. Saraie ◽  
T. Yasui ◽  
S. HA ◽  
H. Matsunami
Keyword(s):  
Molecular Beam Epitaxy ◽  
Visible Light ◽  
Buffer Layer ◽  
Molecular Beam ◽  
Infrared Light ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Good Crystallinity ◽  
Metalorganic Molecular Beam Epitaxy ◽  
Pre Treatment

AbstractGaAs1–xPx (0.2 <; x < 0.7) was grown by metalorganic molecular beam epitaxy with a GaP buffer layer on Si for visible light-emitting devices. Insertion of the GaP buffer layer resulted in bright photoluminescence of the GaAsP epilayer. Pre-treatment of the Si substrate to avoid SiC formation was also critical to obtain good crystallinity of GaAsP. Dislocation formation, microstructure and photoluminescence in GaAsP grown layer are described. A GaAsP pn junction fabricated on GaP emitted visible light (˜1.86 eV). An initial GaAsP pn diode fabricated on Si emitted infrared light.

A Study on the Growth of Cubic GaN Films Using an AlGaAs Buffer Layer Grown on GaAs (100) by Plasma-Assisted Molecular Beam Epitaxy

2000 ◽  
Vol 639 ◽  
Author(s):  
Ryuhei Kimura ◽  
Kiyoshi Takahashi ◽  
H. T. Grahn
Keyword(s):  
Molecular Beam Epitaxy ◽  
Buffer Layer ◽  
Molecular Beam ◽  
High Energy ◽  
Rf Plasma ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cubic Gan

ABSTRACTAn investigation of the growth mechanism for RF-plasma assisted molecular beam epitaxy of cubic GaN films using a nitrided AlGaAs buffer layer was carried out by in-situ reflection high energy electron diffraction (RHEED) and high resolution X-ray diffraction (HRXRD). It was found that hexagonal GaN nuclei grow on (1, 1, 1) facets during nitridation of the AlGaAs buffer layer, but a highly pure, cubic-phase GaN epilayer was grown on the nitrided AlGaAs buffer layer.

GROWTH AND CHARACTERIZATION OF EPITAXIAL Si/CoSi2 AND Si/CoSi2/Si HETEROSTRUCTURES

1985 ◽  
Vol 56 ◽  
Author(s):  
B.D. HUNT ◽  
N. LEWIS ◽  
E.L. HALL ◽  
L.G. JTURNER ◽  
L.J. SCHOWALTER ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Growth Temperature ◽  
Molecular Beam ◽  
Solid Phase ◽  
Solid Phase Epitaxy ◽  
Cross Sectional ◽  
Reactive Deposition ◽  
Ion Channeling ◽  
Formation Method

AbstractThin (<200Å), epitaxial CoSi2 films have been grown on (111) Siwafers in a UHV system using a variety of growth techniques including solid phase epitaxy (SPE), reactive deposition epitaxy (RDE), and molecular beam epitaxy (MBE). SEN and TEN studies reveal significant variations in the epitaxial silicide surface morphology as a function of the sillciqd formation method. Pinhole densities are generally greater than 107 cm-2, although some reduction can be achieved by utilizing proper growth techniques. Si epilayers were deposited over the CoSi2 films inthe temperature range from 550ºC to 800ºC, and the reesuulttinng structures have been characterized using SEM, cross—sectional TEN, and ion channeling measurements. These measurements show that the Si epitaxial quality increases with growth temperature, although the average Si surface roughness and the CoSi2 pinhole density also increase as the growth temperature is raised.

scholarly journals An experimental study on the manufacture and characterization of in-plane fibre-waviness defects in composites

2018 ◽  
Vol 5 (5) ◽  
pp. 180082 ◽  
Author(s):  
W. J. R. Christian ◽  
F. A. DiazDelaO ◽  
K. Atherton ◽  
E. A. Patterson
Keyword(s):  
Residual Strain ◽  
Composite Structures ◽  
Computational Models ◽  
Image Correlation ◽  
Strain Fields ◽  
Strain Measurements ◽  
Ultrasound Measurements ◽  
Residual Strains ◽  
Failure Predictions

A new method has been developed for creating localized in-plane fibre waviness in composite coupons and used to create a large batch of specimens. This method could be used by manufacturers to experimentally explore the effect of fibre waviness on composite structures both directly and indirectly to develop and validate computational models. The specimens were assessed using ultrasound, digital image correlation and a novel inspection technique capable of measuring residual strain fields. To explore how the defect affects the performance of composite structures, the specimens were then loaded to failure. Predictions of remnant strength were made using a simple ultrasound damage metric and a new residual strain-based damage metric. The predictions made using residual strain measurements were found to be substantially more effective at characterizing ultimate strength than ultrasound measurements. This suggests that residual strains have a significant effect on the failure of laminates containing fibre waviness and that these strains could be incorporated into computational models to improve their ability to simulate the defect.

Characterization by ion-channeling of ZnSe grown by photo-assisted molecular beam epitaxy

1993 ◽  
Vol 132 (3-4) ◽  
pp. 575-577
Author(s):  
T. Haga ◽  
M. Ohishi ◽  
K. Imai ◽  
K. Kumazaki ◽  
K. Ohmori ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Ion Channeling
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