Accurate Lattice Constant and Mismatch Measurements of SiC Heterostructures by X-Ray Multiple-Order Reflections

2002 ◽  
Vol 742 ◽  
Author(s):  
XianRong Huang ◽  
Michael Dudley ◽  
Philip G. Neudeck ◽  
J. Anthony Powell
Keyword(s):  
Lattice Mismatch ◽  
Strain Relaxation ◽  
Relaxation Mechanism ◽  
X Ray Diffraction ◽  
Crystalline Perfection ◽  
Coherent Interface ◽  
Rocking Curve ◽  
X Ray ◽  
Lattice Planes ◽  
Atomically Flat

ABSTRACTHigh-resolution X-ray diffraction (HRXRD) combined with other diffraction techniques is applied to characterize 3C SiC epilayers hoteroepitaxially grown on atomically flat mesas on 4H and 6H SiC substrates. Small-beam rocking curve scan and reciprocal mapping show extremely high crystalline perfection and homogeneity of the ideally grown 3C-SiC epilayers. Accurate lattice measurements based on X-ray multiple-order reflections reveal that: 1) no misorientation between the (0001) lattice planes across the 4H/3C or 6H/3C interface is detected, confirming the 2D nucleation mechanism of the 3C epilayer from a flat coherent interface; 2) in-plane substrate/epilayer lattice mismatch always exists, but the 3C epilayers do not correspond to a completely relaxed cubic structure, indicating that the epilayers are partially strained; 3) lattice mismatch varies for different regions, implying a complicated strain relaxation mechanism of 3C epilayers on various mesas.

Epitaxial Batio3 and Knbo3 Thin Films On Various Substrates for Optical Waveguide Applications

1996 ◽  
Vol 441 ◽  
Author(s):  
L. Beckers ◽  
W. Zander ◽  
J. Schubert ◽  
P. Leinenbach ◽  
Ch. Buchal ◽  
...  
Keyword(s):  
Optical Materials ◽  
Rutherford Backscattering Spectrometry ◽  
X Ray Diffraction ◽  
Crystalline Perfection ◽  
Rocking Curve ◽  
X Ray ◽  
Flat Surfaces ◽  
Force Microscopy ◽  
Atomic Force ◽  
Yield Values

AbstractTechnologically interesting optical materials such as BaTiO3 and KnbO3 are difficult to grow as single crystals of large dimensions. Thin film techniques can overcome this problem by synthesizing these materials on commercially available substrates. We demonstrate the deposition of single crystalline BaTiO3 and KnbO3 on MgO, SrTiO3 and buffered MgO substrates by Pulsed Laser Deposition (PLD). The samples are characterized by Rutherford Backscattering Spectrometry / Channeling (RBS/C), X-Ray Diffraction (XRD) and Atomic Force Microscopy (AFM). We found excellent crystalline quality, confirmed by RBS/C minimum yield values of 2 % and a FWHM of 0.36° of the BaTiO3(002) rocking curve. Even films of a few microns thickness have been grown without loss of crystalline perfection, and all films show very flat surfaces. The RMS roughness of a 950 nm BaTiO3 film was found to be 1.1 nm.

Heterostructural Characterization of Pseudomorphic, Partially Strained, and Highly Mismatched Semiconductors Using Double Crystal X-Ray Diffraction, TEM, and SEM

1994 ◽  
Vol 340 ◽  
Author(s):  
Hyung Mun Kim ◽  
Sang-Gi Kim ◽  
Sahn Nahm ◽  
Hyung-Ho Park ◽  
Hae-Kwon Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Lattice Mismatch ◽  
Strain Relaxation ◽  
X Ray Diffraction ◽  
Gaas Sample ◽  
Double Crystal ◽  
Cross Sectional ◽  
X Ray ◽  
Peak Broadening

ABSTRACTHeterostructural properties of pseudomorphic (AlGaAs/GaAs), partially strained (GaInAs/GaAs), and highly strained (GaAs/Si) semiconductor systems have been studied using High Resolution Double-Crystal X-ray Diffraction (DXRD), Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM). Using the high resolution DXRD with CuKα1 and two-reflection Si (220) monochromator, we obtained (004) symmetric and (115) or (224) asymmetric reflection rocking curves for samples grown by molecular beam epitaxy. With 0.5 μm thick samples, perpendicular and in-plane lattice mismatches were calculated using elastic theory and compared with each other. The different degree of relaxation for these samples was observed and correlated with the lattice mismatch, X-ray layer peak broadening (i.e., full width at half maximum), and SEM surface morphology. For a GaInAs/GaAs sample, the strain relaxation along one of the <110> directions was more than the other direction, that is, the strain relaxation is not isotrophic. Also we observed that the lines were mainly parallel in one direction, i.e., they did not form a cross-hatch pattern. TEM images from both cross-sectional and planar views of the samples will be presented.

Strain and Mosaic Structure in Si0.7Ge0.3 Epilayers Grown on Si (001) Substrates Characterized by High Resolution X-Ray Diffraction

1999 ◽  
Vol 594 ◽  
Author(s):  
J. H. Li ◽  
S. C. Moss
Keyword(s):  
Dislocation Density ◽  
Layer Structure ◽  
Strain Relaxation ◽  
Structural Deformation ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Narrow Component ◽  
Low Levels ◽  
Strain Status

AbstractX-ray double- and triple-axis diffractometries were employed to characterize the strain status and structural deformation in Si0.7Ge0.3 alloy layers grown on Si (001) substrates. We show that, at low levels of strain relaxation, x-ray peaks of the Si0.7Ge0.3 alloy layers contain two components, a narrow one superimposed on a broad one. Such a peak profile corresponds to a layer structure consisting of mosaic regions laterally separated by more perfect regions. With the increase in the degree of strain relaxation and consequently in the dislocation density, the narrow component of the x-ray peak gradually disappears as a result of expansion of the mosaic regions and shrinkage or even vanishing of the perfect regions in the layer. Moreover, our results indicate that the conventional method of estimating dislocation density from the x-ray rocking curve width fails in our case.

Measurement of strain in InGaN/GaN nanowires and nanopyramids

2015 ◽  
Vol 48 (2) ◽  
pp. 344-349 ◽  
Author(s):  
Tomaš Stankevič ◽  
Simas Mickevičius ◽  
Mikkel Schou Nielsen ◽  
Olga Kryliouk ◽  
Rafal Ciechonski ◽  
...  
Keyword(s):  
Lattice Mismatch ◽  
Strain Relaxation ◽  
Shell Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Constants ◽  
Shell Nanostructures ◽  
Vegard’S Law ◽  
Planar Films ◽  
The Individual

The growth and optoelectronic properties of core–shell nanostructures are influenced by the strain induced by the lattice mismatch between core and shell. In contrast with planar films, nanostructures contain multiple facets that act as independent substrates for shell growth, which enables different relaxation mechanisms. In this study, X-ray diffraction data are presented that show that InαGa1−αN shells grown on GaN cores are strained along each of the facets independently. Reciprocal space maps reveal multiple Bragg peaks, corresponding to different parts of the shell being strained along the individual facet planes. The strained lattice constants were found from the positions of the Bragg peaks. Vegard's law and Hooke's law for an anisotropic medium were applied in order to find the composition and strain in the InGaN shells. A range of nanowire samples with different InGaN shell thicknesses were measured and it is concluded that, with an In concentration of around 30%, major strain relaxation takes place when the thickness reaches 23 nm. InGaN shells of 6 and 9 nm thickness remain nearly fully strained biaxially along each of the \{10{\overline 1}0\} facets of the nanowires and the \{10{\overline 1}1\} facets of the nanopyramids.

Hydrothermal Epitaxy of I:V Perovskite Thin Films

2002 ◽  
Vol 718 ◽  
Author(s):  
Gregory K. L. Goh ◽  
Suresh K. Donthu
Keyword(s):  
Thin Films ◽  
Hydrothermal Method ◽  
Lattice Mismatch ◽  
X Ray Diffraction ◽  
Island Growth ◽  
Rocking Curve ◽  
X Ray ◽  
Plane Scanning ◽  
Scanning Electron ◽  
Oriented Single Crystal

AbstractAlthough epitaxial II:IV perovskite films like BaTiO3 and Pb(Zr,Ti)O3 have been grown by the hydrothermal method, there are hardly any reports on the growth of I:V perovskite thin films by this low temperature technique. In this study, thin films of NaNbO3, KTaO3 and KNbO3 were grown on (100) oriented single crystal SrTiO3 substrates by the hydrothermal method at 200°C and below. X-ray diffraction (XRD) revealed that the as-synthesized films were epitaxial with one of their original cubic axes normal to the substrate (100) plane. Scanning electron microscopy (SEM) showed that the films formed by an island growth mechanism. KTaO3 was also used as a buffer layer in the growth of KNbO3 films in order to investigate the effect of lattice mismatch on surface morphology and epitaxial quality, as determined by SEM and XRD rocking curve measurements, respectively.

X-ray diffraction properties of curved crystal diffractors

1992 ◽  
Vol 50 (2) ◽  
pp. 1734-1735
Author(s):  
W. Z. Chang ◽  
D. B. Wittry
Keyword(s):  
Diffraction Theory ◽  
X Rays ◽  
Diffraction Image ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Bent Crystal ◽  
Diffraction Geometry ◽  
Crystal Parameter ◽  
Quantitative Procedure

Since Du Mond and Kirkpatrick first discussed the principle of a bent crystal spectrograph in 1930, curved single crystals have been widely utilized as spectrometric monochromators as well as diffractors for focusing x rays diverging from a point. Curved crystal diffraction theory predicts that the diffraction parameters - the rocking curve width w, and the peak reflection coefficient r of curved crystals will certainly deviate from those of their flat form. Due to a lack of curved crystal parameter data in current literature and the need for optimizing the choice of diffraction geometry and crystal materials for various applications, we have continued the investigation of our technique presented at the last conference. In the present abstract, we describe a more rigorous and quantitative procedure for measuring the parameters of curved crystals.The diffraction image of a singly bent crystal under study can be obtained by using the Johann geometry with an x-ray point source.

scholarly journals Simultaneous Multi-Bragg Peak Coherent X-ray Diffraction Imaging

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 312
Author(s):  
Florian Lauraux ◽  
Stéphane Labat ◽  
Sarah Yehya ◽  
Marie-Ingrid Richard ◽  
Steven J. Leake ◽  
...  
Keyword(s):  
Bragg Reflection ◽  
Volume Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal Substrate ◽  
In Series ◽  
Diffraction Imaging ◽  
Diffraction Patterns ◽  
Lattice Planes ◽  
Oriented Parallel

The simultaneous measurement of two Bragg reflections by Bragg coherent X-ray diffraction is demonstrated on a twinned Au crystal, which was prepared by the solid-state dewetting of a 30 nm thin gold film on a sapphire substrate. The crystal was oriented on a goniometer so that two lattice planes fulfill the Bragg condition at the same time. The Au 111 and Au 200 Bragg peaks were measured simultaneously by scanning the energy of the incident X-ray beam and recording the diffraction patterns with two two-dimensional detectors. While the former Bragg reflection is not sensitive to the twin boundary, which is oriented parallel to the crystal–substrate interface, the latter reflection is only sensitive to one part of the crystal. The volume ratio between the two parts of the twinned crystal is about 1:9, which is also confirmed by Laue microdiffraction of the same crystal. The parallel measurement of multiple Bragg reflections is essential for future in situ and operando studies, which are so far limited to either a single Bragg reflection or several in series, to facilitate the precise monitoring of both the strain field and defects during the application of external stimuli.

scholarly journals X-ray imaging of silicon die within fully packaged semiconductor devices

2021 ◽  
pp. 1-7
Author(s):  
Brian K. Tanner ◽  
Patrick J. McNally ◽  
Andreas N. Danilewsky
Keyword(s):  
Synchrotron Radiation ◽  
Feasibility Studies ◽  
Monochromatic Radiation ◽  
X Ray Diffraction ◽  
Divergent Beam ◽  
X Ray ◽  
X Ray Imaging ◽  
Setting Process ◽  
Diffraction Imaging ◽  
Lattice Planes

X-ray diffraction imaging (XRDI) (topography) measurements of silicon die warpage within fully packaged commercial quad-flat no-lead devices are described. Using synchrotron radiation, it has been shown that the tilt of the lattice planes in the Analog Devices AD9253 die initially falls, but after 100 °C, it rises again. The twist across the die wafer falls linearly with an increase in temperature. At 200 °C, the tilt varies approximately linearly with position, that is, displacement varies quadratically along the die. The warpage is approximately reversible on cooling, suggesting that it has a simple paraboloidal form prior to encapsulation; the complex tilt and twisting result from the polymer setting process. Feasibility studies are reported, which demonstrate that a divergent beam and quasi-monochromatic radiation from a sealed X-ray tube can be used to perform warpage measurements by XRDI in the laboratory. Existing tools have limitations because of the geometry of the X-ray optics, resulting in applicability only to simple warpage structures. The necessary modifications required for use in situations of complex warpage, for example, in multiple die interconnected packages are specified.

Time Dependence of γ/γ' Lattice Mismatch in Creep-Deformed Single Crystal Superalloy SC16 at 1173 K

2007 ◽  
Vol 539-543 ◽  
pp. 3059-3063 ◽  
Author(s):  
G. Schumacher ◽  
N. Darowski ◽  
I. Zizak ◽  
Hellmuth Klingelhöffer ◽  
W. Chen ◽  
...  
Keyword(s):  
Single Crystal ◽  
Lattice Mismatch ◽  
Lattice Misfit ◽  
Peak Position ◽  
Single Crystal Superalloy ◽  
Tensile Creep ◽  
Full Width ◽  
X Ray Diffraction ◽  
X Ray ◽  
Time Period

The profiles of 001 and 002 reflections have been measured at 1173 K as a function of time by means of X-ray diffraction (XRD) on tensile-creep deformed specimens of single crystal superalloy SC16. Decrease in line width (full width at half maximum: FWHM) by about 7 % and increase in peak position by about 3x10-4 degrees was detected after 8.5x104 s. Broadening of the 002 peak profile indicated a more negative value of the lattice misfit after the same time period. The results are discussed in the context of the anisotropic arrangement of dislocations at the γ/γ’ interfaces during creep and their rearrangement during the thermal treatment at 1173 K.

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