Manipulating InAs Dots with GaAs Patterns: Effect of GaAs Buffer Layer Growth and Pattern Profiles

1999 ◽  
Vol 571 ◽  
Author(s):  
Søren Jeppesen ◽  
Maria Gerling ◽  
Lars Samuelson ◽  
Mark S. Miller
Keyword(s):  
Buffer Layer ◽  
Photo Luminescence ◽  
Growth Conditions ◽  
High Energy ◽  
Layer Growth ◽  
Chemical Beam Epitaxy ◽  
High Energy Electron ◽  
Force Microscopy ◽  
Atomic Force ◽  
Gaas Buffer Layer

ABSTRACTWe report on our efforts to selectively place chemical beam epitaxy grown Stranski-Krastanov InAs dots on GaAs patterns. The pattern profiles for placement depends on the growth conditions of a GaAs buffer layer grown on the lithographic patterns. Because we seek to suppress dot formation on (100)-oriented surfaces outside of the features, we investigated the effects buffer layer growth conditions have on dot nucleation using reflected high energy electron diffraction, atomic force microscopy and photo-luminescence. We conclude that buffer conditions favorable for patterns have negligible effect on the dots formed on the (100)- oriented surface, and that selective dot placement can be engineered by As pressure, InAs deposition and buffer growth conditions.

Temperature Dependent Quasi-Periodic Facetting of AlAs Grown by MBE on (100) GaAs Substrates

1993 ◽  
Vol 312 ◽  
Author(s):  
Richard Mirin ◽  
Mohan Krishnamurthy ◽  
James Ibbetson ◽  
Arthur Gossard ◽  
John English ◽  
...  
Keyword(s):  
Growth Conditions ◽  
High Energy ◽  
High Energy Electron ◽  
Temperature Dependent ◽  
Cross Sectional ◽  
Mbe Growth ◽  
Atomic Force ◽  
Gaas Substrates ◽  
Transmission Electron ◽  
Facet Formation

AbstractHigh temperature (≥ 650°C) MBE growth of AlAs and AlAs/GaAs superlattices on (100) GaAs is shown to lead to quasi-periodic facetting. We demonstrate that the facetting is only due to the AlAs layers, and growth of GaAs on top of the facets replanarizes the surface. We show that the roughness between the AlAs and GaAs layers increases with increasing number of periods in the superlattice. The roughness increases to form distinct facets, which rapidly grow at the expense of the (100) surface. Within a few periods of the initial facet formation, the (100) surface has disappeared and only the facet planes are visible in cross-sectional transmission electron micrographs. At this point, the reflection high-energy electron diffraction pattern is spotty, and the specular spot is a distinct chevron. We also show that the facetting becomes more pronounced as the substrate temperature is increased from 620°C to 710°C. Atomic force micrographs show that the valleys enclosed by the facets can be several microns long, but they may also be only several nanometers long, depending on the growth conditions.

Direct Measurement of Ion Beam Induced, Nanoscale Roughening of GaN

2005 ◽  
Vol 864 ◽  
Author(s):  
Bentao Cui ◽  
P. I. Cohen ◽  
A. M. Dabiran
Keyword(s):  
Ion Beam ◽  
High Energy ◽  
Surface Relaxation ◽  
Surface Roughening ◽  
High Energy Electron ◽  
Force Microscopy ◽  
Atomic Force ◽  
Continuum Equation ◽  
Argon Ions ◽  
Nanoscale Patterns

AbatractThe formation of ion induced nanoscale patterns such as ripple, dots or pores can be described by a linear continuum equation consisting of a surface roughening term due to curvature-dependent sputtering or asymmetric attachment of vacancies, and a surface smoothing term due to thermal or ion-induced diffusion. By studying ion-induced dimple volume change using atomic force microscopy, we show a method to measure the ion-roughening coefficient. Using this method, we found the roughening coefficient í was 45 nm2/sec at 730K for initial ion etchings with 300 eV Argon ions. Cathodoluminescence measurements indicated Ga-vacancy formation during ion bombardment. The activation energy for surface relaxation after ion etching was about 0.12 eV as measured by reflection high energy electron diffraction.

On the nucleation of GaP/GaAs and the effect of buried stress fields

2005 ◽  
Vol 891 ◽  
Author(s):  
João Guilherme Zelcovit ◽  
José Roberto R. Bortoleto ◽  
Jefferson Bettini ◽  
Mônica Cotta
Keyword(s):  
Three Dimensional ◽  
High Energy ◽  
In Situ Monitoring ◽  
Chemical Beam Epitaxy ◽  
Contact Mode ◽  
Force Microscopy ◽  
Compositional Modulation ◽  
Atomic Force ◽  
Spatial Ordering ◽  
Periodic Stress

ABSTRACTWe have recently shown that spatial ordering for epitaxially grown InP dots can be obtained using the periodic stress field of compositional modulation on the InGaP buffer layer. The aim of this present work is to study the growth of films of GaP by Chemical Beam Epitaxy (CBE), with in-situ monitoring by Reflection High Energy Electron Diffraction (RHEED), on layers of unstressed and stressed GaAs. Complementary, we have studied the role of a buried InP dot array on GaP nucleation in order to obtain three-dimensional structures. In both cases, the topographical characteristics of the samples were investigated by Atomic Force Microscopy (AFM) in non-contact mode. Thus vertically-coupled quantum dots of different materials have been obtained keeping the in-place spatial ordering originated from the composition modulation.

Reflection High Energy Electron Diffraction and Atomic Force Microscopy Studies of MnxSc(1-x) Alloys Grown on MgO(001) Substrates by Molecular Beam Epitaxy

2011 ◽  
Vol 1295 ◽  
Author(s):  
Costel Constantin ◽  
Abhijit Chinchore ◽  
Arthur R. Smith
Keyword(s):  
Atomic Force Microscopy ◽  
Molecular Beam Epitaxy ◽  
Electron Diffraction ◽  
Molecular Beam ◽  
High Energy ◽  
Energy Electron ◽  
High Energy Electron ◽  
Force Microscopy ◽  
Atomic Force ◽  
Growth Method

ABSTRACTThe combination of the molecular beam epitaxy growth method with the in-situ reflection high energy electron diffraction measurements currently offers unprecedented control of crystalline growth materials. We present here a stoichiometric study of MnxSc(1-x) [x = 0, 0.03, 0.05, 0.15, 0.25, 0.35, and 0.50] thin films grown on MgO(001) substrates with this growth method. Reflection high energy electron diffraction and atomic force microscopy measurements reveal alloy behavior for all of our samples. In addition, we found that samples Mn0.10Sc0.90 and Mn0.50Sc0.50 display surface self-assembled nanowires with a length/width ratio of ~ 800 – 2000.

Epitaxy of Al films on GaN studied by reflection high-energy electron diffraction and atomic force microscopy

1997 ◽  
Vol 70 (8) ◽  
pp. 990-992 ◽  
Author(s):  
Q. Z. Liu ◽  
L. Shen ◽  
K. V. Smith ◽  
C. W. Tu ◽  
E. T. Yu ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Electron Diffraction ◽  
High Energy ◽  
Energy Electron ◽  
High Energy Electron ◽  
Force Microscopy ◽  
Atomic Force

Drastic Change in the Gan Film Quality by In-Situ Controlling Surface Reconstructions In Gsmbe

1997 ◽  
Vol 482 ◽  
Author(s):  
X. Q. Shen ◽  
S. Tanaka ◽  
S. Iwai ◽  
Y. Aoyagi
Keyword(s):  
Growth Conditions ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Gas Source ◽  
Atomic Force ◽  
Surface Reconstructions ◽  
Gan Film

AbstractGaN growth was performed on 6H-SiC (0001) substrates by gas-source molecular beam epitaxy (GSMBE), using ammonia (NH3) as a nitrogen source. Two kinds of reflection high-energy electron diffraction (RHEED) patterns, named (1×1) and (2×2), were observed during the GaN growth depending on the growth conditions. By careful RHEED study, it was verified that the (1×1) pattern was corresponded to a H2-related nitrogen-rich surface, while (2×2) pattern was resulted from a Ga-rich surface. By x-ray diffraction (XRD), photoluminescence (PL) and atomic force microscopy (AFM) characterizations, it was found that the GaN quality changed drastically grown under different RHEED patterns. GaN film grown under the (1×1) RHEED pattern showed much better qualities than that grown under the (2×2) one.

Epitaxial Growth of AlN on 6H-SiC (1120) by Molecular-Beam Epitaxy and Effect of Low-Temperature Buffer Layer

2002 ◽  
Vol 743 ◽  
Author(s):  
N. Onojima ◽  
J. Suda ◽  
H. Matsunami
Keyword(s):  
Molecular Beam Epitaxy ◽  
Low Temperature ◽  
Buffer Layer ◽  
Molecular Beam ◽  
High Energy ◽  
Rf Plasma ◽  
Epitaxial Relationship ◽  
Raman Scattering Spectroscopy ◽  
Force Microscopy ◽  
Atomic Force

ABSTRACTAluminum nitride (AlN) has been grown on 6H-silicon carbide (SiC) substrates with the non-polar (1120) face using rf plasma-assisted molecular-beam epitaxy (rf-MBE). Reflection high-energy electron diffraction (RHEED) revealed that AlN and 6H-SiC (1120) had an exact epitaxial relationship, i.e., [1120]AlN|[1120]SiC and [0001]AlN∥[0001]SiC. From the result of microscopic Raman scattering spectroscopy, the stacking structure of the AlN epitaxial layer was suggested to be a 2H structure, not a 6H structure. A directly grown AlN layer and layer with AlN low-temperature (LT) buffer layer were investigated based on atomic force microscopy (AFM) and X-ray diffraction (XRD).

Reflection High Energy Electron Diffraction Studies of the Growth of DyBa2Cu3O7−x Films and Structures Grown on SrTiO3 Substrates

1992 ◽  
Vol 275 ◽  
Author(s):  
V. S. Achutharaman ◽  
N. Chandrasekhar ◽  
A. M. Goldman
Keyword(s):  
Electron Diffraction ◽  
Specular Reflection ◽  
Growth Conditions ◽  
High Energy ◽  
Layer Growth ◽  
Energy Electron ◽  
Layer By Layer ◽  
High Energy Electron ◽  
Epitaxial Relationship ◽  
Superlattice Structures

ABSTRACTIntensity oscillations of the specular reflection high energy electron diffraction (RHEED) beam contain useful information on the mode of growth and the evolving structure of thin films. We present RHEED studies of the growth of DyBa2Cu3O7−x films and DyBa2Cu3O7−x/DY2O3/DyBa2Cu3O7−x structures on SrTiO3; substrates deposited by ozone-assisted molecular beam epitaxy. The effect of substrate temperature, ozone flux and surface step densities on the epitaxial relationship and evolving microstructure will be discussed. The strong damping of the oscillations and identical time periods under different nuoleation and growth conditions suggest that the intensity oscillations are a consequence of to diffuse scattering from step edges rather than a layer-by-layer growth mode. It was also found that Dy2O3 can be used to fabricatee tri-layer type structures but not superlattice structures.

Preparation of (111)-Oriented Pt Electrode Films with Quasi-Monocrystal Properties on MgO/TiN Buffered Si(100) by PLD

2007 ◽  
Vol 280-283 ◽  
pp. 823-826 ◽  
Author(s):  
Tong Lai Chen ◽  
Xiao Min Li
Keyword(s):  
High Energy ◽  
Layer Growth ◽  
Atomic Scale ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Pt Electrode ◽  
Force Microscopy ◽  
Atomic Force

Atomic-scale smooth Pt electrode films have been deposited on MgO/TiN buffered Si (100) by the pulsed laser deposition (PLD) technique. The whole growth process of the multilayer films was monitored by using in-situ reflection high energy electron diffraction (RHEED) apparatus. The Pt/MgO/TiN/Si(100) stacked structure was also characterized by X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). The HREED observations show that the growth mode of the Pt electrode film is 2D layer-by-layer growth. It is found that the (111)-oriented Pt electrode film has a crystallinity comparable to that of monocrystals. The achievement of the quasi-single-crystal Pt electrode film with an atomic-scale smooth surface is ascribed to the improved crystalline quality of the MgO film.

Comparative Growth of AIN on Singular and Off-Axis 6H and 4H-SiC by MOCVD

1998 ◽  
Vol 537 ◽  
Author(s):  
S. Wilson ◽  
C. S. Dickens ◽  
J. Griffin ◽  
M. G. Spencer
Keyword(s):  
High Energy ◽  
Two Dimensional ◽  
Comparison Study ◽  
High Energy Electron ◽  
High Quality ◽  
Force Microscopy ◽  
Step Flow ◽  
Atomic Force ◽  
Dimensional Growth ◽  
Atomically Flat

AbstractA comparison study of the growth of aluminum nitride (AIN) single crystal epitaxy on 6H-SiC and 4H-SiC substrates has been performed. The material has been characterized using atomic force microscopy (AFM) and reflective high energy electron diffraction (RHEED). AIN crystals were deposited on the following 6H-SiC substrates: singular with and without an initial SiC epilayer, and 3.5° off-axis with and without an initial SIC epilayer. AIN crystals were deposited on 8.0° off-axis 4H-SiC with and without initial SIC epilayers. AFM shows that the deposition of AIN on 6H-SiC and 4H-SIC with an initial SiC epilayer displays high quality quasi-two dimensional growth as atomically flat or step flow epitaxy.

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