Epitaxial tilt of partially relaxed InGaAs layers grown on (100) GaAs substrates

1992 ◽  
Vol 70 (10-11) ◽  
pp. 838-842
Author(s):  
P. Maigné ◽  
A. P. Roth ◽  
C. Desruisseaux ◽  
D. Coulas
Keyword(s):  
Residual Strain ◽  
Gaas Substrate ◽  
Strain Relaxation ◽  
Azimuthal Angle ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Monoclinic Symmetry ◽  
X Ray ◽  
Mismatch Strain ◽  
Gaas Substrates

The structural properties of partially relaxed InxGa1−xAs layers grown on (100) GaAs substrates have been investigated, using high-resolution X-ray diffraction, in order to better understand the mechanisms responsible for the relaxation of the mismatch strain. From symmetric [400] reflections recorded as functions of the azimuthal angle [Formula: see text], the (100) InGaAs planes are found to be tilted with respect to the (100) GaAs substrate planes. The tilt magnitude is first seen to decrease then to increase with layer thickness. The direction of the tilt changes from [01-1] to [00-1] in the range of thickness investigated. From [422] asymmetric reflections, the average in-plane lattice parameter, the indium composition as well as the percentage of relaxation can be measured. Our values for relaxation are in qualitative agreement with the Dodson and Tsao model of strain relaxation (Appl. Phys. Lett. 51, 1710 (1987)). In addition, our data show an anisotropy in residual strain along <011> directions. This anisotropy increases with the amount of strain relieved and changes the crystal symmetry of the cell from tetragonal to monoclinic. This monoclinic symmetry can be characterized by an angle β that measures the angle between 90° and the inner angles of the new crystallographic cell. As for the anisotropy in residual strain, |3 increases with the amount of strain relieved. Correlations between tilt magnitude and tilt direction with the formation of 60° type dislocations are discussed.

scholarly journals Grazing-incidence X-ray diffraction of single GaAs nanowires at locations defined by focused ion beams

2013 ◽  
Vol 46 (4) ◽  
pp. 887-892 ◽  
Author(s):  
Genziana Bussone ◽  
Rüdiger Schott ◽  
Andreas Biermanns ◽  
Anton Davydok ◽  
Dirk Reuter ◽  
...  
Keyword(s):  
Gaas Substrate ◽  
Lattice Spacing ◽  
Molecular Beam ◽  
Grazing Incidence ◽  
Lattice Parameter ◽  
Ion Beams ◽  
Focused Ion Beams ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gaas Nanowires

Grazing-incidence X-ray diffraction measurements on single GaAs nanowires (NWs) grown on a (111)-oriented GaAs substrate by molecular beam epitaxy are reported. The positions of the NWs are intentionally determined by a direct implantation of Au with focused ion beams. This controlled arrangement in combination with a nanofocused X-ray beam allows the in-plane lattice parameter of single NWs to be probed, which is not possible for randomly grown NWs. Reciprocal space maps were collected at different heights along the NW to investigate the crystal structure. Simultaneously, substrate areas with different distances from the Au-implantation spots below the NWs were probed. Around the NWs, the data revealed a 0.4% decrease in the lattice spacing in the substrate compared with the expected unstrained value. This suggests the presence of a compressed region due to Au implantation.

Double Axis X-Ray Diffractometry Analysis of the Homoepitaxial Interface Between Substrate and Buffer Layer

1990 ◽  
Vol 208 ◽  
Author(s):  
G. Stephan Green ◽  
Brian K. Tanner ◽  
Philip Kightley
Keyword(s):  
Buffer Layer ◽  
Interfacial Layer ◽  
Gaas Substrate ◽  
Interface Layer ◽  
Lattice Parameter ◽  
Good Match ◽  
Low Contrast ◽  
X Ray ◽  
Gaas Substrates ◽  
Transmission Electron

ABSTRACTHigh resolution double axis X-ray diffractometry has been undertaken on InGaAs/AlGaAs strained layer epitaxial systems on (001) GaAs substrates. A clear set of fringes has been identified which arises due to the presence of an imperfect layer at the interface between the GaAs substrate and the undoped GaAs epitaxial buffer layer. The period corresponds to the Pendellosung period for the whole epitaxial layer stack. These fringes have very low contrast and are not present in all specimens studied. Detailed simulations have been undertaken assuming a thin interfacial layer of GaAs with a different lattice parameter to the substrate. The system is equivalent to a Bragg case X-ray interferometer. Fringe amplitude is found to vary linearly with interface layer thickness and increases with mismatch of this layer. A good match between experiment and simulation was obtained for a 1 nm layer mismatched by 3000 ppm. The presence of such a layer, probably GaCxAsl-x has been confirmed by transmission electron microscopy. We show that highly sh'rained layers of this thickness between layers over 1 micron in thickness can lead to splitting of high intensity layer peaks, giving rise to possible misinterpretation of data.

Characterizations Of Zr/Si1-x-yGexCy After Rapid Thermal Annealing

1998 ◽  
Vol 533 ◽  
Author(s):  
V. Aubry-Fortuna ◽  
M. Barthula ◽  
F. Meyer ◽  
A. Eyal ◽  
C. Cytermann ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Schottky Barrier ◽  
Rapid Thermal Annealing ◽  
Residual Strain ◽  
Strain Relaxation ◽  
Small Strain ◽  
X Ray Diffraction ◽  
X Ray ◽  
Barrier Heights ◽  
Final Compound

AbstractIn this work, we have investigated the reaction between Zr and SiGeC alloys after Rapid Thermal anneals performed at 800°C for 5 min. The interactions of the metal with the alloy have been investigated by X-Ray diffraction. Four crystal X-Ray diffraction was also performed to measure the residual strain in the epilayer. The final compound of the reaction is the C49- Zr(Si1-xGex)2 phase. The C49 film contains the same Ge concentration as in the as-deposited Si1-x-yGexCy layer. This suggests that no Ge-segregation occurs during annealing. Only a small strain relaxation is detected in the unreacted SiGe epilayer during the reaction. The addition of C in the epilayer prevents any strain relaxation. These results are in contrast with those observed in systems with Ti and Co, and show that the system Zr-Si-Ge is much more stable. Schottky barrier heights have been also measured: annealing leads to a slight decrease of the barrier without any degradation of the contact. The resistivity of the C49 film is about 80 μΩcm. These results indicate that Zr may be a good candidate for contacts on IV-IV alloys in term of thermal stability.

Effect of substrate orientation on strain relaxation mechanisms of InGaAs layer grown on vicinal GaAs substrates measured by in situ X-ray diffraction

2017 ◽  
Vol 56 (8S2) ◽  
pp. 08MA06 ◽  
Author(s):  
Hidetoshi Suzuki ◽  
Takuo Sasaki ◽  
Masamitu Takahasi ◽  
Yoshio Ohshita ◽  
Nobuaki Kojima ◽  
...  
Keyword(s):  
Strain Relaxation ◽  
Ingaas Layer ◽  
X Ray Diffraction ◽  
Substrate Orientation ◽  
X Ray ◽  
Gaas Substrates

Mapping the Strain State of 3C-SiC/Si (001) Suspended Structures Using μ-XRD

2016 ◽  
Vol 858 ◽  
pp. 274-277 ◽  
Author(s):  
Gerard Colston ◽  
Stephen D. Rhead ◽  
Vishal Ajit Shah ◽  
Oliver J. Newell ◽  
Igor P. Dolbnya ◽  
...  
Keyword(s):  
Convenient Method ◽  
Residual Strain ◽  
Tensile Strain ◽  
Strain State ◽  
Strain Relaxation ◽  
Lattice Parameters ◽  
Raman Shift ◽  
X Ray Diffraction ◽  
X Ray ◽  
Direct Measurements

The residual strain has been mapped across suspended 3C-SiC membranes and wires using synchrotron based micro X-ray diffraction (μ-XRD). Residual tensile strain is observed to relax slightly upon suspension in both sets of structures. Similar maps were acquired by calculating the residual strain from the shift in 3C-SiC Raman peaks. Comparable trends in strain relaxation are observed by both methods, although the sensitivity of μ-XRD is higher using our measurement conditions. While Raman shift provides a fast and convenient method for mapping strain variations, it cannot give direct measurements of the lattice parameters that can be achieved with μ-XRD, making these techniques excellent complimentary methods of mapping residual strain in 3C-SiC.

Quaternary Alloys InxAlyGa1−x-yAs Grown on GaAs with A Compositionally-Step-Graded Buffer

1992 ◽  
Vol 263 ◽  
Author(s):  
C. Fan ◽  
D. W. Shih ◽  
M. W. Hansen ◽  
J. Chen ◽  
P. Z. Lee ◽  
...  
Keyword(s):  
Schottky Barrier ◽  
Lattice Mismatch ◽  
Chemical Reactivity ◽  
Compressive Strain ◽  
X Ray Diffraction ◽  
Quaternary Alloys ◽  
X Ray ◽  
Mismatch Strain ◽  
Barrier Heights ◽  
Gaas Substrates

ABSTRACTFundamental bandgaps and Schottky barrier heights of strain-relaxed quaternary InxAlyGa1−x-yAs alloys with 0 < x < 0.35 and 0 < y < 0.30 were studied. The alloys were grown on GaAs substrates by molecular beam epitaxy. The lattice mismatch (up to 2.5%) and mismatch strain were accommodated by a compositionally-step-graded buffer. A residual compressive strain of less than 0.5% was determined by x-ray diffraction. Measured Schottky barrier heights v.s. bandgap deviate from the values predicted by the “commonanion” rule. This behavior is attributed to the compositional inhomogeneities and chemical reactivity of the air-exposed InAlGaAs surfaces.

The Evolution of Strain Relaxation Close to The Critical Thickness

1993 ◽  
Vol 317 ◽  
Author(s):  
P. Kidd ◽  
P.F. Fewster
Keyword(s):  
Residual Strain ◽  
Strain Field ◽  
Critical Thickness ◽  
Strain Relaxation ◽  
Epitaxial Layers ◽  
X Ray Diffraction ◽  
Strain Fields ◽  
X Ray ◽  
Local Relaxation ◽  
Homogeneous Strain

ABSTRACTHigh resolution X-ray diffraction space mapping has been used to follow the change in the distribution of residual strain and localised relaxation in low mismatched epitaxial layers. Using this new technique, we have obtained a series of diffraction space maps of partially relaxed epitaxial layers of In.1Ga.9As on GaAs. The layers have different thicknesses and hence different degrees of strain relaxation. The diffuse scatter close to the Bragg peaks provides information about the imperfect and distorted regions in the structure and this has allowed us to examine the extent and distribution of residual strain close to the dislocations. We have followed the evolution of local relaxation, which is confined initially to regions around isolated dislocations, through to the case of overlapping dislocation strain fields, leading to a more homogeneous strain field distribution and microscopic and macroscopic tilting of the layers.

Epitaxial Layer Misorientation in CdTe on GaAs‡

1990 ◽  
Vol 202 ◽  
Author(s):  
H. E. Inglefield ◽  
R. J. Matyi ◽  
R. Korenstein
Keyword(s):  
Epitaxial Layer ◽  
Gaas Substrate ◽  
Dislocation Model ◽  
Azimuthal Direction ◽  
X Ray Diffraction ◽  
Azimuthal Dependence ◽  
X Ray ◽  
Gaas Substrates ◽  
Cdte Films ◽  
Hot Wall Epitaxy

ABSTRACTX-ray diffraction has been used to characterize the relative misorientation of [001] and [111] CdTe layers grown by hot-wall epitaxy on GaAs substrates. The magnitude of the misorientation of the CdTe epitaxial layer relative to the GaAs substrate depends on the magnitude of the miscut of the substrate; in addition, the [111] oriented CdTe exhibited significantly larger misorientations than did the [001] CdTe films. The azimuthal direction of the tilt of the epitaxial layer depends strongly on the nominal crystallographic orientation of the film. The [111] CdTe exhibited an azimuthal dependence of the tilt that is approximately coincident with the miscut of the substrate, while the azimuthal direction of tilt in the [001] CdTe layers differed from the substrate miscut direction by as much as 116°. These observations of epitaxial layer misorientation are discussed in terms of a dislocation model for layer tilt and azimuthal rotation in lattice-mismatched epitaxial systems.

POSSIBLE ABNORMAL MECHANISM FOR LATTICE STRAIN RELAXATION IN La0.7Ca0.3MnO3 THIN FILM

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2415-2420 ◽  
Author(s):  
W. S. TAN ◽  
Q. J. JIA ◽  
J. GAO
Keyword(s):  
Critical Thickness ◽  
Lattice Strain ◽  
Strain Relaxation ◽  
Grazing Incidence ◽  
Lattice Parameter ◽  
Radio Frequency Magnetron Sputtering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lcmo Film ◽  
Oriented Single Crystal

La 0.7 Ca 0.3 MnO 3(LCMO) thin films with the thickness of 50 nm were deposited on (001)-oriented single crystal SrTiO 3(STO), MgO and α- Al 2 O 3(ALO) by 90° off-axis radio frequency magnetron sputtering. Grazing incidence X-ray diffraction technique, associated with normal X-ray diffraction, was performed to measure the in-plane lattice parameter and investigate the lattice strain and strain relaxation in LCMO films. The results indicated that critical thickness of strain relaxation is very small, which may be related to large mismatch between film and substrate. The mechanism for strain relaxation in LCMO film is perhaps different from that for tetragonal distortion.

Ordered Ternary Alloys by Atomic Layer Epitaxy

1989 ◽  
Vol 160 ◽  
Author(s):  
B.T. Mcdermott ◽  
K.G. Reid ◽  
A. Dip ◽  
N.A. El-Masry ◽  
S.M. Bed Air ◽  
...  
Keyword(s):  
Gas Phase ◽  
Growth Temperature ◽  
Gaas Substrate ◽  
Atomic Layer ◽  
Ternary Alloys ◽  
Atomic Layer Epitaxy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Matching ◽  
Gaas Substrates

AbstractWe report on the successful growth of GalnP on GaAs substrate by Atomic Layer Epitaxy using organometallic and hydride sources. Growth was achieved by sequential exposure of the substrate to TMGa, PH3, TEIn and PH3. X-ray diffraction showed compositional lattice-matching optimally at 550°C with arbitrary choices of the mole fractions of the precursors in the gas phase. TEM also confirmed the highest ordering at this growth temperature on (100) substrates. Uniformity was excellent using Atomic Layer Epitaxy. Growth on (111)A GaAs substrates produced no evidence of the ordered CuPt phase present on (100) substrates.

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