X-Ray Standing Wave and High Resolution Diffraction Study of Si/Ge Superlattices

1995 ◽  
Vol 379 ◽  
Author(s):  
S. Lagomarsino ◽  
P. Castrucci ◽  
P. Calicchia ◽  
A. Cedola ◽  
A. Kazimirov
Keyword(s):  
High Resolution ◽  
Standing Wave ◽  
Structural Characteristics ◽  
Structural Parameters ◽  
Phase 1 ◽  
Modern Technology ◽  
Characterization Methods ◽  
X Ray ◽  
Optimal Behavior ◽  
Strong Reflection

ABSTRACTIn modern technology more and more attention is given to epitaxial superlattices. III/V, and more recently Si/Ge superlattices are widely studied because of their applications in integrated optoelectronics. Since the physical properties are strongly dependent on structural characteristics, it is evident that accurate characterization methods are required in order to improve their quality and obtain optimal behavior. X-ray high resolution diffraction is extensively and successfully used to this purpose. In general diffracted intensity is measured close to strong substrate reflections where satellite peaks from superlattice take place. If the crystalline quality, mainly concerning thickness layer uniformity and interface abruptness is good, several orders of diffraction from the superlattice are visible, and fitting based on kinematical or dynamical diffraction can provide information about many structural parameters of the superlattice. However from diffracted intensity the information about the phase of the structure factor is lost. It is well known that the X-ray Standing Wave (XSW) technique can provide direct information about the phase [1]. In this paper we present measurements and calculations relative to the extension of the XSW method to the study of MBE-grown Si/Ge superlattices. The novelty consists in using the superlattice satellite peaks close to a strong reflection from the substrate to form the standing wave field which in turn excites the atoms whose fluorescence is measured. These satellite peaks correspond to high-order diffraction for the superlattice periodicity.

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

High-resolution X-ray diffraction and X-ray standing wave analyses of (AlAs)m(GaAs)nshort-period superlattices

1995 ◽  
Vol 28 (4A) ◽  
pp. A206-A211 ◽  
Author(s):  
M Schuster ◽  
A Lessmann ◽  
A Munkholm ◽  
S Brennan ◽  
G Materliks ◽  
...  
Keyword(s):  
High Resolution ◽  
Standing Wave ◽  
X Ray Diffraction ◽  
X Ray

Microbeam high-resolution diffraction and x-ray standing wave methods applied to semiconductor structures

2004 ◽  
Vol 37 (4) ◽  
pp. L9-L12 ◽  
Author(s):  
A Kazimirov ◽  
D H Bilderback ◽  
R Huang ◽  
A Sirenko ◽  
A Ougazzaden
Keyword(s):  
High Resolution ◽  
Standing Wave ◽  
X Ray ◽  
Semiconductor Structures ◽  
Wave Methods

Structural Perfection of in GaAs/InP Superlattices Grown by Gas Source Molecular Beam Epitaxy: A High-Resolution X-Ray Diffraction Study

1987 ◽  
Vol 103 ◽  
Author(s):  
J. M. Vandenberg ◽  
M. B. Panish ◽  
R. A. Hamm
Keyword(s):  
High Resolution ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Structural Parameters ◽  
Molecular Layer ◽  
X Ray Diffraction ◽  
Structural Perfection ◽  
X Ray ◽  
Gas Source ◽  
Step Model

ABSTRACTHigh-resolution X-ray diffraction (HRXRD) studies have been cardied out to determine the structural perfection and periodicity for a number of high-quality InGaAsfInP superlattices grown by gas source molecular beam epitaxy. X-ray scans were carried out with a compact four-crystal monochromator resulting in a resolution of one molecular layer (∼3,Å), which enables one to observe very small variations in the periodic structure. Sharp and strong higher-order satellite reflections in the XRD profiles were observed indicating smooth interfaces with well-defined modulated structures. Excellent computer simulated fits of the X-ray satellite pattern could be generated based on a kinematical XRD step model which assumes ideally sharp interfaces, and periodic structural parameters such as the strain in the well could be extracted. Our results3 demonstrate that HRXRD in conjunction with the kinematical step model is a very sensitive method to assess periodic structural modifications in superlattices as a result of the precise growth conditions in the gas source MBE system.

High resolution x-ray diffractometry of the structural characteristics of a semiconducting (InGa)As/GaAs superlattice

1999 ◽  
Vol 44 (2) ◽  
pp. 171-179 ◽  
Author(s):  
Ya. I. Nesterets ◽  
V. I. Punegov ◽  
K. M. Pavlov ◽  
N. N. Faleev
Keyword(s):  
High Resolution ◽  
Structural Characteristics ◽  
X Ray

High-resolution x-ray diffraction study of In0.25Ga0.75Sb/InAs superlattice

1999 ◽  
Vol 14 (5) ◽  
pp. 1744-1751 ◽  
Author(s):  
A. Vigliante ◽  
H. Homma ◽  
J. T. Zborowski ◽  
T. D. Golding ◽  
S. C. Moss
Keyword(s):  
High Resolution ◽  
Structural Parameters ◽  
Reciprocal Lattice ◽  
Lattice Points ◽  
Diffuse Interface ◽  
X Ray Diffraction ◽  
Group V ◽  
X Ray ◽  
Strained Layer Superlattice ◽  
Ir Detection

An In0.25Ga0.75Sb/InAs strained-layer superlattice, grown by molecular-beam epitaxy (MBE) on a GaSb[001] substrate, has been characterized by four-circle x-ray diffractometry. This system, proposed by Maliot and Smith for ir detection application, is challenging because of the two group V species and the likelihood of cross-incorporation of the different elements during growth, leading possibly to interdiffusion and thus, to a more diffuse interface. High-resolution x-ray diffraction (XRD) profiles were obtained about several reciprocal lattice points in order to extract a reliable set of structural parameters. The profiles were then successfully modeled by computer simulation. The presence of many sharp higher-order satellite reflections in the XRD profiles is a measure of the high quality of the superlattices. The normal and lateral structural coherence was also measured and will be discussed.

Study of structural characteristics of the FePt nanosystem by TEM

2020 ◽  
Vol 63 (7) ◽  
pp. 79-84
Author(s):  
Yury A. Zaharov ◽  
◽  
Nikita S. Zaharov ◽  
Anna N. Popova ◽  
Dmitry M. Russakov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Structural Analysis ◽  
Structural Characteristics ◽  
Structural Parameters ◽  
Fept Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Tem Method

In this work, using the example of a bimetallic nanoscale system FePt, a new approach to the assessment of the structural parameters of nanoscale mono- and polymetallic systems by transmission electron microscopy (TEM) is proposed. The data obtained by the TEM method are compared with the data obtained by the method of X-ray structural analysis. Some crystallographic parameters, such as the interplanar distances, average sizes, and phase compositions of the studied nanoparticles of the FePt system are calculated. The most widespread method for obtaining information about the crystal structure of nanosized particles is the method based on the phenomenon of X-ray diffraction. It allows one to determine the phase composition and perform structural analysis of a substance, as well as to estimate the size of the resulting particles. In this method, crystallographic information arises due to X-ray diffraction from the entire surface of the powder. Thus, the researcher sees an integral diffraction pattern. In this case, the study of individual nanoparticles by X-ray structural analysis is extremely difficult. However, the number of methods for assessing structural parameters is not limited to X-ray diffraction methods. In this work, an approach is made to study the structural characteristics of FePt nanoparticles by transmission electron microscopy (TEM), since high-resolution microimages obtained by the TEM method provide a unique opportunity to distinguish individual atoms of the crystal lattice of the objects under study.

Determination of YBaCuO thin layer structural parameters by using high-resolution X-ray diffractometry

1995 ◽  
Vol 28 (4A) ◽  
pp. A212-A215 ◽  
Author(s):  
T S Argunova ◽  
R N Kyutt ◽  
M P Scheglov ◽  
N N Faleev
Keyword(s):  
High Resolution ◽  
Thin Layer ◽  
Structural Parameters ◽  
X Ray

High Resolution X-Ray Diffraction Analysis Of Gallium Nitride Grown On Sapphire By Halide Vapor Phase Epitaxy

1996 ◽  
Vol 423 ◽  
Author(s):  
R. J. Matyi ◽  
D. Zhi ◽  
N. R. Perkins ◽  
M. N. Horton ◽  
T. F. Kuech
Keyword(s):  
High Resolution ◽  
Vapor Phase ◽  
Structural Characteristics ◽  
Vapor Phase Epitaxy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sapphire Substrates ◽  
Order Of Magnitude ◽  
Mosaic Distribution ◽  
Peak Widths

AbstractWe report a structural analysis of GaN layers with thicknesses ranging from 10 μm to 250 μm which have been grown on sapphire substrates by halide vapor phase epitaxy (HVPE). The effect of growth rate during HVPE growth has also been examined. The growth was performed using GaCl and ammonia as reactants; growth rates in excess of 90 μm/hr have been achieved. The structural characteristics of these layers have been performed wit'i high resolution x-ray diffractometry. Longitudinal scans parallel to the GaN [0002] direction, transverse scans perpendicular to the [0002], and reciprocal space maps of the total diffracted intensity have been obtained from a variety of GaN layers. The transverse scans typically show broad rocking curves with peak breadths of several hundreds of arcseconds. In contrast, the longitudinal scans (or “θ/2θ scans”) which are sensitive only to strains in the GaN layers (and not their mosaic distributions) showed peak widths that were at least an order of magnitude smaller and in some cases were as narrow as 16 arcseconds. These results suggest that the defect structure of the GaN layers grown by HVPE is dominated by a dislocation-induced mosaic distribution, with the effects of strain in these materials being negligible in comparison.

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