Tem Study of the Structure of Mbe GaAs Layers Grown at Low Temperature

1990 ◽  
Vol 198 ◽  
Author(s):  
Zuzanna Liliental-Weber
Keyword(s):  
Electron Microscopy ◽  
Low Temperature ◽  
Molecular Beam ◽  
Critical Thickness ◽  
Stacking Faults ◽  
Structural Quality ◽  
Crystalline Perfection ◽  
Transmission Electron ◽  
Low Temperature Gaas

ABSTRACTThe structural quality of GaAs layers grown at 200°C by molecular beam epitaxy (MBE) was investigated by transmission electron microscopy (TEM). We found that a high crystalline perfection can be achieved in the layers grown at this low temperature for thickness up to 3 μm. In some samples we observed pyramid-shaped defects with polycrystalline cores surrounded by microtwins, stacking faults and dislocations. The size of these cores increased as the growth temperature was decreased and as the layer thickness was increased. The upper surface of layers with pyramidal defects became polycrystalline at a critical thickness of the order of 3μm. We suggested that the low-temperature GaAs becomes polycrystalline at a critical thickness either because of a decrease in substrate temperature during growth or because strain induced by excess As incorporated in these layers leads to the formation of misoriented GaAs nuclei, thereby initiating polycrystalline growth. The pyramidal shape of the defects results from a growth-rate hierarchy of the low index planes in GaAs.

Dependence of the Defects Present in InAlAs/InP on the Substrate Temperature

1991 ◽  
Vol 240 ◽  
Author(s):  
F. Peiro ◽  
A. Cornet ◽  
A. Herms ◽  
J. R. Morante ◽  
A. Georgakilas ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Substrate Temperature ◽  
Molecular Beam ◽  
Stacking Faults ◽  
Structural Defects ◽  
Threading Dislocations ◽  
Transmission Electron ◽  
Inp Substrates

ABSTRACTThe crystalline quality of InAlAs layers, grown by Molecular Beam Epitaxy on (100) InP substrates, has been investigated by Transmission Electron Microscopy in order to study the influence of InAlAs growth temperature (Tg) on the density of structural defects present in the layers. Tg was varied from 300°C up to 530°C. The density of stacking faults and threading dislocations drops dramatically as Tg increas

scholarly journals Epitaxial Growth of Ordered In-Plane Si and Ge Nanowires on Si (001)

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 788
Author(s):  
Jian-Huan Wang ◽  
Ting Wang ◽  
Jian-Jun Zhang
Keyword(s):  
Electron Microscopy ◽  
Epitaxial Growth ◽  
Molecular Beam ◽  
Core Shell ◽  
High Quality ◽  
Quantum Devices ◽  
Wafer Scale ◽  
Transmission Electron ◽  
Controllable Growth

Controllable growth of wafer-scale in-plane nanowires (NWs) is a prerequisite for achieving addressable and scalable NW-based quantum devices. Here, by introducing molecular beam epitaxy on patterned Si structures, we demonstrate the wafer-scale epitaxial growth of site-controlled in-plane Si, SiGe, and Ge/Si core/shell NW arrays on Si (001) substrate. The epitaxially grown Si, SiGe, and Ge/Si core/shell NW are highly homogeneous with well-defined facets. Suspended Si NWs with four {111} facets and a side width of about 25 nm are observed. Characterizations including high resolution transmission electron microscopy (HRTEM) confirm the high quality of these epitaxial NWs.

Structure of InAs Quantum Dots in Si Matrix Investigated by High Resolution Electron Microscopy

1999 ◽  
Vol 571 ◽  
Author(s):  
N. D. Zakharov ◽  
P. Werner ◽  
V. M. Ustinov ◽  
A.R. Kovsh ◽  
G. E. Cirlin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Critical Thickness ◽  
High Resolution Electron Microscopy ◽  
Geometrical Parameters ◽  
Inas Quantum Dots ◽  
Temperature Growth ◽  
Transmission Electron ◽  
Resolution Electron

ABSTRACTQuantum dot structures containing 2 and 7 layers of small coherent InAs clusters embedded into a Si single crystal matrix were grown by MBE. The structure of these clusters was investigated by high resolution transmission electron microscopy. The crystallographic quality of the structure severely depends on the substrate temperature, growth sequence, and the geometrical parameters of the sample. The investigation demonstrates that Si can incorporate a limited volume of InAs in a form of small coherent clusters about 3 nm in diameter. If the deposited InAs layer exceeds a critical thickness, large dislocated InAs precipitates are formed during Si overgrowth accumulating the excess of InAs.

scholarly journals Influence of Low Temperature-Grown GaAs on Lateral Thermal Oxidation of Al0.98Ga0.02As

2000 ◽  
Vol 623 ◽  
Author(s):  
J. C. Ferrer ◽  
Z. Liliental-Weber ◽  
H. Reese ◽  
Y.J. Chiu ◽  
E. Hu
Keyword(s):  
Low Temperature ◽  
Thermal Oxidation ◽  
Oxidation Process ◽  
Gaas Layer ◽  
Transmission Electron ◽  
Low Temperature Gaas ◽  
Reference Samples ◽  
Thermal Oxidation Process ◽  
Low Temperature Grown Gaas

AbstractThe lateral thermal oxidation process of Al0.98Ga0.02As layers has been studied by transmission electron microscopy. Growing a low-temperature GaAs layer below the Al0.98Ga0.02As has been shown to result in better quality of the oxide/GaAs interfaces compared to reference samples. While the later have As precipitation above and below the oxide layer and roughness and voids at the oxide/GaAs interface, the structures with low-temperature have less As precipitation and develop interfaces without voids. These results are explained in terms of the diffusion of the As toward the low temperature layer. The effect of the addition of a Si02 cap layer is also discussed.

scholarly journals Morphology and surface reconstructions of m-plane GaN

2002 ◽  
Vol 743 ◽  
Author(s):  
C. D. Lee ◽  
R. M. Feenstra ◽  
J. E. Northrup ◽  
L. Lymperakis ◽  
J. Neugebauer
Keyword(s):  
Molecular Beam Epitaxy ◽  
Low Temperature ◽  
Surface Morphology ◽  
Buffer Layer ◽  
Molecular Beam ◽  
Structural Quality ◽  
Surface Reconstructions ◽  
Gan Buffer Layer

ABSTRACTM-plane GaN(1100) is grown by plasma assisted molecular beam epitaxy on ZnO(1100) substrates. A low-temperature GaN buffer layer is found to be necessary to obtain good structural quality of the films. Well oriented (1100) GaN films are obtained, with a slate like surface morphology. On the GaN(1100) surfaces, reconstructions with symmetry of c(2×2) and approximate “4×5” are found under N- and Ga-rich conditions, respectively. We propose a model for Ga-rich conditions with the “4×5” structure consisting of ≥ 2 monolayers of Ga terminating the GaN surface.

The Influence of the Temperature Gradient on the Defect Structure of 3C-SiC Grown Heteroepitaxially on 6H-SiC by Sublimation Epitaxy

2010 ◽  
Vol 645-648 ◽  
pp. 367-370 ◽  
Author(s):  
Maya Marinova ◽  
Alkyoni Mantzari ◽  
Milena Beshkova ◽  
Mikael Syväjärvi ◽  
Rositza Yakimova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Temperature Gradient ◽  
Defect Structure ◽  
Temperature Gradients ◽  
Structural Quality ◽  
Fault Density ◽  
Transmission Electron

In the present work the structural quality of 3C-SiC layers grown by sublimation epitaxy is studied by means of conventional and high resolution transmission electron microscopy. The layers were grown on Si-face 6H-SiC nominally on-axis substrates at a temperature of 2000°C and different temperature gradients, ranging from 5 to 8 °C /mm. The influence of the temperature gradient on the structural quality of the layers is discussed. The formation of specific twin complexes and conditions for lower stacking fault density are investigated.

Molecular Beam Epitaxial Growth of Cdl-xznxTe Matched to HgCdTe Alloys

1986 ◽  
Vol 90 ◽  
Author(s):  
N. Magnea ◽  
F. Dal'bo ◽  
J. L. Pautrat ◽  
A. Million ◽  
L. Di Cioccio ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molecular Beam ◽  
Bulk Material ◽  
Strained Layers ◽  
Molecular Beam Epitaxial ◽  
Transmission Electron ◽  
Molecular Beam Epitaxial Growth ◽  
Thick Layers

ABSTRACTCD1−xZnxTe alloys of various composition have been grown by the Molecular Beam Epitaxy Technique and characterized by Transmission Electron Microscopy. C(V) measurements and photoluminescence spectroscopy techniques. The quality of the thick layers is comparable to that of bulk material. Thin strained layers have also been grown whose interfaces are structurally good. The recombination within a CdTe well confined between Cd1−xZnxTe barriers is dominated by intrinsic processes.

A Study on the Strain and Microstructure in SiGe Film Grown on Si(001) Substrate by MBE

1994 ◽  
Vol 356 ◽  
Author(s):  
Kyoung-Ik Cho ◽  
Sahn Nahm ◽  
Sang-Gi Kim ◽  
Seung-Chang Lee ◽  
Kyung-Soo Kim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Molecular Beam ◽  
Large Strain ◽  
Strain Relaxation ◽  
Stacking Faults ◽  
Double Crystal ◽  
Crystalline Layer ◽  
X Ray ◽  
Transmission Electron ◽  
Plain Strain

AbstractSi/Si0.8Ge0.2/Si(001) structures were grown at various growth temperatures (250 ∼ 760 °C) using molecular beam epitaxy, and the variation of strain and microstructure of the film was investigated using double crystal X-ray diffractometry and transmission electron microscopy. SiGe films with good single crystallinity were obtained at the growth temperatures of 440 ∼ 600 °C. For the samples grown below 350 °C, an amorphous SiGe film was developed over the SiGe single crystalline layer with a jagged amorphous/crystalline (a/c) interface, and many defects such as stacking faults and microtwins were formed below the a/c interface. Dislocations were developed through out the films for the samples grown above 680 °C. In addition, for the samples grown below 680 °C, the amount of in-plane strain of the SiGe film was found to be about − 8×l0−3 without strain relaxation. However, the SiGe films grown at 760 °C have small in-plain strain of − 4×l0−3 and large strain relaxation of 50%.

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