Reduced threading dislocation densities in high-T/N-rich grown InN films by plasma-assisted molecular beam epitaxy

2013 ◽  
Vol 102 (5) ◽  
pp. 051916 ◽  
Author(s):  
Bernhard Loitsch ◽  
Fabian Schuster ◽  
Martin Stutzmann ◽  
Gregor Koblmüller
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Threading Dislocation ◽  
Dislocation Densities

scholarly journals Снижение плотности прорастающих дислокаций в темплейтах AlN/c-сапфир, выращенных методом плазменно-активированной молекулярно-пучковой эпитаксии

2020 ◽  
Vol 46 (8) ◽  
pp. 36
Author(s):  
В.В. Ратников ◽  
Д.В. Нечаев ◽  
А.В. Мясоедов ◽  
О.А. Кошелев ◽  
В.Н. Жмерик
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Flux Ratio ◽  
Buffer Layers ◽  
Stress Generation ◽  
Threading Dislocation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Regimes ◽  
Dislocation Densities

Multiple-crystal X-ray diffraction and a multi-beam optical stress sensor were used to study AlN/c-sapphire templates grown by plasma-assisted molecular beam epitaxy. The influence of the nucleation and buffer layers growth regimes, temperature, the ratio between Al and N* growth fluxes on the stress generation and the character of the dislocation structure were analyzed. Templates with the best crystal quality with screw and edge threading dislocation densities in a range of 4∙10^8 and 8∙10^9 cm-2, respectively, were obtained at the flux ratio of Al to N* close to 1 by using two-stage temperature regimes.

Photoluminescence intensity of GaN films with widely varying dislocation density

2003 ◽  
Vol 18 (5) ◽  
pp. 1247-1250 ◽  
Author(s):  
Yue Jun Sun ◽  
Oliver Brandt ◽  
Klaus H. Ploog
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Geometrical Model ◽  
Nonradiative Recombination ◽  
Photoluminescence Intensity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dislocation Densities ◽  
Recombination Centers ◽  
The Impact

We investigated the impact of the presence of dislocations on room-temperature photoluminescence intensity in GaN films grown by molecular beam epitaxy. To determine both screw and edge dislocation densities, we employed x-ray diffraction in conjunction with a geometrical model, which relate the width of the respective reflections to the polar and azimuthal orientational spread. There is no direct dependence of the emission efficiency on the density of either type of dislocation in the samples under investigation. We conclude that dislocations are not the dominant nonradiative recombination centers for GaN grown by molecular beam epitaxy.

Relaxed Si1−xGex films with reduced dislocation densities grown by molecular beam epitaxy

1995 ◽  
Vol 157 (1-4) ◽  
pp. 121-125 ◽  
Author(s):  
Martin O. Tanner ◽  
Michael A. Chu ◽  
Kang L. Wang ◽  
Marjohn Meshkinpour ◽  
Mark S. Goorsky
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Dislocation Densities

Effect of the Introduction of a MBE Buffer Layer on the Morphology of InSb Almbe Layers Grown on InP Substrates

1995 ◽  
Vol 399 ◽  
Author(s):  
J.C. Ferrer ◽  
A. Cornet ◽  
F. Peiró ◽  
J.R. Morante ◽  
T. Utzmeier ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Lattice Mismatch ◽  
Three Dimensional ◽  
Atomic Layer ◽  
Buffer Layers ◽  
Dislocation Network ◽  
Threading Dislocation ◽  
Large Lattice Mismatch ◽  
Inp Substrates

ABSTRACTIn this paper we report on the morphology of InSb layers grown by atomic layer molecular beam epitaxy (ALMBE) onto InP substrates at low temperatures (330<T<400°C), comparing the nature and densities of defects with those found in ALMBE InSb films grown over InSb/InP buffer layers grown by molecular beam epitaxy (MBE). The main types of defects for ALMBE direct layers are threading dislocations and stacking faults with similar defect densities along both á110ñ directions. The inclusion of the intermediate InSb/InP MBE grown buffer layers leads to lower threading dislocation densities but higher and anisotropic stacking fault distribution. Moreover, different types of three-dimensional defects appear, which are associated with pyramidal or truncated pyramidal hillocks on the surface. These defects, consisting in twins associations are originated at the InSb/InP MBE interface and they are induced by an anomalous growth of InSb layers. In all the cases, the strain caused by the large lattice mismatch is accommodated by means of a pure edge-type misfit dislocation network placed at the interface.

Relaxed Si1−xGex films with reduced dislocation densities grown by molecular beam epitaxy

1996 ◽  
pp. 121-125
Author(s):  
Martin O. Tanner ◽  
Michael A. Chu ◽  
Kang L. Wang ◽  
Marjohn Meshkinpour ◽  
Mark S. Goorsky
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Dislocation Densities

Growth of Metamorphic InGaP for Wide-Bandgap Photovoltaic Junction by MBE

2010 ◽  
Vol 1268 ◽  
Author(s):  
John Simon ◽  
Stephanie Tomasulo ◽  
Paul Simmonds ◽  
Manuel J Romero ◽  
Minjoo Larry Lee
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molecular Beam ◽  
Strain Relaxation ◽  
Wide Bandgap ◽  
Threading Dislocation ◽  
Step Size ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Substrate Temperatures

AbstractMetamorphic triple-junction solar cells can currently attain efficiencies as high as 41.1%. Using additional junctions could lead to efficiencies above 50%, but require the development of a wide bandgap (2.0-2.2eV) material to act as the top layer. In this work we demonstrate wide bandgap InyGa1-yP grown on GaAsxP1-x via solid source molecular beam epitaxy. Unoptimized tensile GaAsxP1-x buffers grown on GaAs exhibit asymmetric strain relaxation, along with formation of faceted trenches 100-300 nm deep in the [01-1] direction. Smaller grading step size and higher substrate temperatures minimizes the facet trench density and results in symmetric strain relaxation. In comparison, compressively-strained graded GaAsxP1-x buffers on GaP show nearly-complete strain relaxation of the top layers and no evidence of trenches. We subsequently grew InyGa1-yP layers on the GaAsxP1-x buffers. Photoluminescence and transmission electron microscopy measurements show no indication of phase separation or CuPt ordering. Taken in combination with the low threading dislocation densities obtained, MBE-grown InyGa1-yP layers are promising candidates for future use as the top junction of a multi-junction solar cell.

scholarly journals Single-Crystalline Si1−xGex (x = 0.5~1) Thin Films on Si (001) with Low Threading Dislocation Density Prepared by Low Temperature Molecular Beam Epitaxy

2019 ◽  
Vol 9 (9) ◽  
pp. 1772
Author(s):  
Gu ◽  
Zhao ◽  
Ye ◽  
Deng ◽  
Lu
Keyword(s):  
Thin Films ◽  
Molecular Beam Epitaxy ◽  
Low Temperature ◽  
Dislocation Density ◽  
Molecular Beam ◽  
Strain Relaxation ◽  
Relaxation Mechanism ◽  
Threading Dislocation ◽  
Threading Dislocation Density ◽  
Typical Strain

Single-crystalline Si1−xGex thin films on Si (100) with low threading dislocation density (TDD) are highly desired for semiconductor industrials. It is challenging to suppress the TDD since there is a large mismatch (4.2%) between Ge and Si—it typically needs 106–107/cm2 TDD for strain relaxation, which could, however, cause device leakage under high voltage. Here, we grew Si1−xGex (x = 0.5–1) films on Si (001) by low temperature molecular beam epitaxy (LT-MBE) at 200 °C, which is much lower than the typical temperature of 450–600 °C. Encouragingly, the Si1−xGex thin films grown by LT-MBE have shown a dramatically reduced TDD down to the 103–104/cm2 level. Using transmission electron microscopy (TEM) with atomic resolution, we discovered a non-typical strain relaxation mechanism for epitaxial films grown by LT-MBE. There are multiple-layered structures being introduced along out-of-plane-direction during film growth, effectively relaxing the large strain through local shearing and subsequently leading to an order of magnitude lower TDD. We presented a model for the non-typical strain relaxation mechanism for Si1−xGex films grown on Si (001) by LT-MBE.

Transport in High-Mobility Si1−xGex Heterostructures Grown by Molecular-Beam Epitaxy

1992 ◽  
Vol 281 ◽  
Author(s):  
Don Monroe ◽  
Y.-H. Xie ◽  
E. A. Fitzgerald ◽  
P. J. Silverman
Keyword(s):  
Molecular Beam Epitaxy ◽  
Hall Effect ◽  
Molecular Beam ◽  
High Mobility ◽  
Interface Roughness ◽  
Buffer Layers ◽  
Threading Dislocation ◽  
Fractional Quantum Hall ◽  
Angle Scattering ◽  
Interface Roughness Scattering

ABSTRACTWe report Hall mobilities (at T = 4.2K) as high as 180,000cm2V−1 s−1 in modulation-doped Si layers in Si1−x Gex heterostructures grown by Molecular-Beam Epitaxy. These mobilities reflect dramatic improvements in the quality of relaxed Si1−xGex buffer layers (with x'30%) grown by gradual grading of composition at high temperature. The resulting moderate threading dislocation densities (< 106 cm−2 ) appear to cause no mobility degradation. The strong damping of Shubnikov de Haas oscillations, as well as the increase of mobility with carrier density, indicate predominantly small-angle scattering. This suggests that residual Coulomb scattering from background impurities limit the mobility, rather than interface-roughness scattering as for the Si/SiO2 interface. The reduced interfacial scattering, as well as the strain-induced splitting of the valley degeneracy to select the two low-effective-mass valleys, significantly enhance room-temperature transport as well, with μHall ' 2,100cm2 V−1 s−1. We also observe a small splitting of the remaining twofold valley degeneracy using the integral quantized Hall effect. As a further indication of the high sample quality, measurements to 17T at 0.3K show indications of the v = 2/3 fractional quantum Hall effect.

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