Effects of Stress-relieving AlN Interlayers in GaN-on-Si Grown by Plasma-assisted Molecular Beam Epitaxy

2008 ◽  
Vol 1068 ◽  
Author(s):  
Adam Adikimenakis ◽  
Suman-Lata Sahonta ◽  
George Dimitrakopulos ◽  
Jaroslav Domagala ◽  
Philomela Komninou ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Plasma Source ◽  
Rf Plasma ◽  
X Ray Diffraction ◽  
Inversion Domain ◽  
Transmission Electron ◽  
Stress Relieving ◽  
Gan On Si ◽  
Inversion Domain Boundaries

ABSTRACTThe insertion of an AlN interlayer for tensile strain relief in GaN thin films grown on Si (111) on-axis and vicinal substrates by nitrogen rf plasma source molecular beam epitaxy has been investigated. The 15 nm AlN interlayer was inserted between the bottom 0.5 micron GaN layer and the top 1.0 micron GaN layer. The interlayer was very effective to reduce the tensile stress in the overall 1.5 micron GaN/Si film to the level required for complete avoidance of microcracks, which were present in high densities in GaN/Si heterostructures grown without an AlN interlayer. The strain of the AlN interlayer, as well as the strain in all the layers of the entire GaN/Si heterostructure was analyzed by x-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements. Reciprocal space map in XRD indicated that the 15 nm AlN interlayer was coherently strained with the GaN films. However TEM observations revealed that the AlN interlayer was partially relaxed in local regions. The AlN interlayer was also observed to interfere with the GaN growth process. In particular, above morphological features such as V-defects, GaN was overgrown with a large density of threading dislocations and inversion domain boundaries.

Characterization of GaN grown on sapphire by laser-induced molecular beam epitaxy

2001 ◽  
Vol 16 (1) ◽  
pp. 261-267 ◽  
Author(s):  
H. Zhou ◽  
A. Rühm ◽  
N. Y. Jin-Phillipp ◽  
F. Phillipp ◽  
M. Gross ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
X Ray Diffraction ◽  
Fringe Contrast ◽  
Inversion Domain ◽  
Transmission Electron ◽  
Contrast Analysis ◽  
Inversion Domain Boundaries

GaN grown on sapphire (α–Al2O3) was characterized by laser-induced molecular beam epitaxy. Threading dislocations with Burgers vectors of 1/3〈1120〉, 1/3〈1123〉 and [0001] were observed with a predominance of the first type. Additionally, inversion domains with Ga-polarity existed with respect to the adjacent matrix, which was of N-polarity. The dislocation densities and coherence lengths were deduced from x-ray diffraction and found to be in accordance with those measured by transmission electron microscopy. Both displacement fringe contrast analysis and high-resolution transmission electron microscopy results indicated that the inversion domain boundaries had Ga–N bonds between domains and the adjacent matrix.

Microstructral Investigations on GaN Films Grown by Laser Induced Molecular Beam Epitaxy

1999 ◽  
Vol 595 ◽  
Author(s):  
H. Zhou ◽  
F. Phillipp ◽  
M. Gross ◽  
H. Schröder
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Threading Dislocations ◽  
Planar Defects ◽  
Sapphire Substrates ◽  
Inversion Domain ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Line Defects ◽  
Inversion Domain Boundaries

AbstractMicrostructural investigations on GaN films grown on SiC and sapphire substrates by laser induced molecular beam epitaxy have been performed. Threading dislocations with Burgers vectors of 1/3<1120>, 1/3<1123> and [0001] are typical line defects, predominantly the first type of dislocations. Their densities are typically 1.5×1010 cm−2 and 4×109 cm−2 on SiC and sapphire, respectively. Additionally, planar defects characterized as inversion domain boundaries lying on {1100} planes have been observed in GaN/sapphire samples with an inversion domain density of 4×109 cm−2. The inversion domains are of Ga-polarity with respect to the N-polarity of the adjacent matrix. However, GaN layers grown on SiC show Ga-polarity. Possible reasons for the different morphologies and structures of the films grown on different substrates are discussed. Based on an analysis of displacement fringes of inversion domains, an atomic model of the IDB-II with Ga-N bonds across the boundary was deduced. High resolution transmission electron microscopy (HRTEM) observations and the corresponding simulations confirmed the IDB-II structure determined by the analysis of displacement fringes.

The Effect of Hydrogen on the Molecular-Beam-Epitaxy Growth of GaN on Sapphire Under Ga-Rich Conditions

1996 ◽  
Vol 449 ◽  
Author(s):  
S. L. Buczkowski ◽  
Zhonghai Yu ◽  
M. Richards-Babb ◽  
N. C. Giles ◽  
L. T. Romano ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Growth Kinetics ◽  
Atomic Hydrogen ◽  
Molecular Beam ◽  
Plasma Source ◽  
Nucleation And Growth ◽  
Rf Plasma ◽  
Molecular Beam Epitaxy Growth ◽  
Dramatic Effect ◽  
Inversion Domain

ABSTRACTNucleation and growth of GaN under Ga-rich conditions by molecular beam epitaxy using a nitrogen rf plasma source is shown to result in both a smoother GaN surface and a reduced inversion domain content. In addition, preliminary results of the dramatic effect of atomic hydrogen on growth kinetics for Ga-rich growth are presented.

Structural and Optical Properties of InAsSbBi Grown by Molecular Beam Epitaxy on Offcut GaSb Substrates

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 215
Author(s):  
Rajeev R. Kosireddy ◽  
Stephen T. Schaefer ◽  
Marko S. Milosavljevic ◽  
Shane R. Johnson
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Optical Quality ◽  
X Ray Diffraction ◽  
Interface Quality ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Lateral Variations

Three InAsSbBi samples are grown by molecular beam epitaxy at 400 °C on GaSb substrates with three different offcuts: (100) on-axis, (100) offcut 1° toward [011], and (100) offcut 4° toward [011]. The samples are investigated using X-ray diffraction, Nomarski optical microscopy, atomic force microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The InAsSbBi layers are 210 nm thick, coherently strained, and show no observable defects. The substrate offcut is not observed to influence the structural and interface quality of the samples. Each sample exhibits small lateral variations in the Bi mole fraction, with the largest variation observed in the on-axis growth. Bismuth rich surface droplet features are observed on all samples. The surface droplets are isotropic on the on-axis sample and elongated along the [011¯] step edges on the 1° and 4° offcut samples. No significant change in optical quality with offcut angle is observed.

A Study on the Growth of Cubic GaN Films Using an AlGaAs Buffer Layer Grown on GaAs (100) by Plasma-Assisted Molecular Beam Epitaxy

2000 ◽  
Vol 639 ◽  
Author(s):  
Ryuhei Kimura ◽  
Kiyoshi Takahashi ◽  
H. T. Grahn
Keyword(s):  
Molecular Beam Epitaxy ◽  
Buffer Layer ◽  
Molecular Beam ◽  
High Energy ◽  
Rf Plasma ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cubic Gan

ABSTRACTAn investigation of the growth mechanism for RF-plasma assisted molecular beam epitaxy of cubic GaN films using a nitrided AlGaAs buffer layer was carried out by in-situ reflection high energy electron diffraction (RHEED) and high resolution X-ray diffraction (HRXRD). It was found that hexagonal GaN nuclei grow on (1, 1, 1) facets during nitridation of the AlGaAs buffer layer, but a highly pure, cubic-phase GaN epilayer was grown on the nitrided AlGaAs buffer layer.

Structural Defects in GaN Epilayers Grown by Gas Source Molecular Beam Epitaxy

1989 ◽  
Vol 162 ◽  
Author(s):  
Z. Sitar ◽  
M. J. Paisley ◽  
B. Yan ◽  
R. F. Davis
Keyword(s):  
Electron Cyclotron Resonance ◽  
Plasma Source ◽  
Structural Defects ◽  
Effusion Cell ◽  
Gas Source ◽  
Inversion Domain ◽  
Transmission Electron ◽  
Gas Source Mbe ◽  
Inversion Domain Boundaries ◽  
Resonance Plasma

ABSTRACTSingle crystal cubic or hexagonal GaN thin films have been grown on various substrates, using a modified gas source MBE technique. A standard effusion cell was employed for the evaporation of gallium. A compact electron cyclotron resonance plasma source was used to activate the nitrogen prior to deposition. The films were examined by transmission electron microscopy. The major defects in the wurtzite GaN were double positioning boundaries, inversion domain boundaries, and dislocations. The zinc-blende GaN showed microtwins, stacking faults, and dislocations. The connection between the observed structural defects and the poor electrical properties of GaN is noted.

Epitaxial Growth and Characterization of the Ordered Vacancy Compound CuIn3Se5 on GaAs (100) Fabricated by Molecular Beam Epitaxy

1994 ◽  
Vol 340 ◽  
Author(s):  
Art J. Nelson ◽  
M. Bode ◽  
G. Horner ◽  
K. Sinha ◽  
John Moreland
Keyword(s):  
Molecular Beam Epitaxy ◽  
Epitaxial Growth ◽  
Molecular Beam ◽  
Structural Defects ◽  
X Ray Diffraction ◽  
Symmetric Vibration ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

ABSTRACTEpitaxial growth of the ordered vacancy compound (OVC) CuIn3Se5 has been achieved on GaAs (100) by molecular beam epitaxy (MBE) from Cu2Se and In2Se3 sources. Electron probe microanalysis and X-ray diffraction have confirmed the composition for the 1-3-5 OVC phase and that the film is single crystal Culn3Se5 (100). Transmission electron microscopy (TEM) characterization of the material also showed it to be single crystalline. Structural defects in the layer consisted mainly of stacking faults. Photoluminescence (PL) measurements performed at 7.5 K indicate that the bandgap is 1.28 eV. Raman spectra reveal a strong polarized peak at 152 cm−1, which is believed to arise from the totally symmetric vibration of the Se atoms in the lattice. Atomic force microscopy reveals faceting in a preferred (100) orientation.

Interrelation between Strain Relaxation and InxAl1-xAs Compositional Graded Step Buffer Layers on GaAs Substrate Grown by Molecular Beam Epitaxy

2007 ◽  
Vol 124-126 ◽  
pp. 127-130
Author(s):  
Sook Hyun Hwang ◽  
Yu Mi Park ◽  
Hoon Ha Jeon ◽  
Kyung Seok Noh ◽  
Jae Kyu Kim ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Gaas Substrate ◽  
Molecular Beam ◽  
Strain Relaxation ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
Compositional Gradient ◽  
Transmission Electron ◽  
Two Samples ◽  
Compositional Gradients

We have grown delta-doped In0.5Ga0.5As /In0.5Al0.5As heterostructures on GaAs substrate applying with InxAl1-xAs compositional graded-step buffers, called metamorphic structures, grown by molecular beam epitaxy. Three types of buffer layers with different compositional gradients and thicknesses have designed to investigate the influence of the strain relaxation process. We characterized the samples by using transmission electron microscopy, triple-axis X-ray diffraction and Hall measurement. Two samples with different compositional gradient show almost same results in electrical properties. On the other hand, it is found that samples with different step thicknesses had shown the large differences in epilayer tilt and mosaic spread in the step-graded buffers. These results indicate that there exists an interrelation between the strain-relaxed buffer and 2DEG transport properties.

Double Periodicity Formation in EuTe/PbTe Superlattices

1995 ◽  
Vol 399 ◽  
Author(s):  
M. Shima ◽  
L. Salamanca-Riba ◽  
G. Springholz ◽  
G. Bauer
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Short Period ◽  
Short Period Superlattices

ABSTRACTMolecular beam epitaxy was used to grow EuTe(x)/PbTe(y) short period superlattices with x=1-4 EuTe(111) monolayers alternating with y≈3x PbTe monolayers. The superlattices were characterized by transmission electron microscopy and high resolution x-ray diffraction. Regions with double periodicity were observed coexisting with areas of nominal periodicity. The sample with x=3.5 and y=9, for example, contains regions with double periodicity of x=7 and y=17. X-ray diffraction measurements confirm the formation of the double periodicity in these samples by the appearance of weak satellites in between the satellites of the nominal periodicity. The double periodicity in the superlattice is believed to result from interdiffusion during the growth. A model for this process is presented.

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