Preparation of InN and InN-Based Heterostructures by Molecular Beam Epitaxy

2001 ◽  
Vol 680 ◽  
Author(s):  
Hai Lu ◽  
William J. Schaff ◽  
Jeonghyun Hwang ◽  
Lester F. Eastman
Keyword(s):  
Molecular Beam Epitaxy ◽  
Carrier Concentration ◽  
Buffer Layer ◽  
Molecular Beam ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
Optimum Growth Temperature ◽  
Migration Enhanced Epitaxy ◽  
Dimensional Electron Gas ◽  
Aln Buffer

ABSTRACTInN is an important III-V compound semiconductor with many potential microelectronic and optoelectronic applications. In this study, we prepared epitaxial InN on (0001) sapphire with an AlN buffer layer by molecular beam epitaxy, and its variation, migration enhanced epitaxy. A series of samples were grown with different substrate temperatures ranging from 360°C to 590°C. The optimum growth temperature for InN was found to be between 450°C and 500°C. We also found that thicker AlN buffer layers result in the best InN quality. With increasing thickness of an AlN buffer layer, the Hall electron mobility of InN increases while the carrier concentration decreases. The surface morphology is also improved this way. Hall mobility greater than 800 cm2/Vs with carrier concentration 2-3×1018 cm−3 at room temperature can be routinely obtained for ∼0.1[.proportional]m thick InN films. Various InN-based heterostructures with AlInN or AlN barrier were fabricated. X-ray diffraction study clearly shows the barrier and InN layers. A 2-dimensional electron gas resulting from polarization induced electrons was observed in capacitance-voltage measurements. Some results on Mg doping of InN will be discussed as well.

Twinning in epilayers of CdTe on Si: Influence of ZnTe buffer layer and substrate misorientation

1995 ◽  
Vol 399 ◽  
Author(s):  
A. Gray ◽  
N.K. Dhar ◽  
W. Clark ◽  
P. Charlton ◽  
J.H. Dinan ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Buffer Layer ◽  
Molecular Beam ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates

ABSTRACTX-ray diffraction spectra of CdTe epilayers grown with and without ZnTe buffer layers on <211> Si substrates by molecular beam epitaxy consist of 422 and 331 reflections. We interpret these as evidence for the existence of twins within the volume of a <211> oriented epilayer and show that twin volume is dependent on the ZnTe buffer layer and substrate misorientation.

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.

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.

Study of high quality AlN layers grown on Si(111) substrates by plasma-assisted molecular beam epitaxy

1997 ◽  
Vol 2 ◽  
Author(s):  
M. A. Sánchez-García ◽  
E. Calleja ◽  
E. Monroy ◽  
F. J. Sánchez ◽  
F. Calle ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Growth Conditions ◽  
Buffer Layers ◽  
Structural Quality ◽  
Half Maximum ◽  
High Quality ◽  
Force Microscopy ◽  
Aln Buffer ◽  
Xrd Techniques

High quality AlN layers with full widths at half maximum values of 10 arcmin and average surface roughness (rms) of 48Å were grown by molecular beam epitaxy on Si(111) substrates. A systematic study and optimization of the growth conditions was performed in order to use these AlN layers as buffers in the growth of GaN films. Atomic force microscopy (AFM) and X-ray diffraction (XRD) techniques were employed to determine the surface and structural quality of the layers. Best AlN films were obtained at high substrate temperatures (Tsubs>900°C) and III/V ratios close to stoichiometry. Growth conditions with III/V ratios beyond stoichiometry (Al-rich) did not further improve the crystal quality. In these cases a higher substrate temperature is needed to prevent condensation of Al on the surface. GaN films with full width at half maximum of 10 arcmin and improved optical properties were grown on top of optimized AlN buffer layers.

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.

scholarly journals Effect of Aluminum Nitride Buffer Layer Deposited by Molecular Beam Epitaxy on the Growth of Aluminum Nitride Thin Films Deposited by DC Magnetron Sputtering Technique

2021 ◽  
Author(s):  
B. Riah ◽  
Julien Camus ◽  
Abdelhak Ayad ◽  
Mohammad Rammal ◽  
Raouia Zernadji ◽  
...  
Keyword(s):  
Thin Films ◽  
Molecular Beam Epitaxy ◽  
Low Temperature ◽  
Aluminum Nitride ◽  
Magnetron Sputtering ◽  
Epitaxial Growth ◽  
Buffer Layer ◽  
Molecular Beam ◽  
Dc Magnetron Sputtering ◽  
Aln Buffer

This paper reports the effect of silicon substrate orientation and aluminum nitride buffer layer deposited by molecular beam epitaxy on the growth of aluminum nitride thin films deposited by DC magnetron sputtering technique at low temperature. The structural analysis has revealed a strong (0001) fiber texture for both substrates Si (100) and (111) and a hetero-epitaxial growth on few nanometers AlN buffer layer grown by MBE on Si (111) substrate. SEM images and XRD characterization have shown an enhancement in AlN crystallinity thanks to AlN (MBE) buffer layer. Raman spectroscopy indicated that the AlN film was relaxed when it deposited on Si (111), in compression on Si (100) and under tension on AlN buffer layer grown by MBE/Si (111) substrates, respectively. The interface between Si (111) and AlN grown by MBE is abrupt and well defined; contrary to the interface between AlN deposited using PVD and AlN grown by MBE. Nevertheless, AlN hetero-epitaxial growth was obtained at low temperature (&lt;250&deg;C).

scholarly journals Separation of AlN layers from silicon substrates by KOH etching

2021 ◽  
Vol 2086 (1) ◽  
pp. 012037
Author(s):  
K Yu Shubina ◽  
D V Mokhov ◽  
T N Berezovskaya ◽  
E V Pirogov ◽  
A V Nashchekin ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Surface Damage ◽  
Vapour Phase ◽  
Buffer Layers ◽  
Silicon Substrates ◽  
Vapour Phase Epitaxy ◽  
Aln Buffer ◽  
Cr Film ◽  
Koh Etching

Abstract In this work, the AlN/Si(111) epitaxial structures grown consistently by plasma assisted molecular beam epitaxy (PA MBE) and hydride vapour phase epitaxy (HVPE) methods were studied. The PA MBE AlN buffer layers were synthesized via coalescence overgrowth of self-catalyzed AlN nanocolumns on Si(111) substrates and were used as templates for further HVPE growth of thick AlN layer. It was shown that described approaches can be used to obtain AlN layers with sufficiently smooth morphology. It was found that HVPE AlN inherited crystallographic polarity of the AlN layer grown by PA MBE. It was demonstrated that the etching of such AlN/Si(111) epitaxial structures results in partial separation of the AlN epilayers from the Si(111) substrate and allows to form suspended structures. Moreover, the avoidance of surface damage and backside overetching was achieved by use thin Cr film as surface protective coating and by increasing the layer thickness accordingly.

Fabrication and characterization of ZnMgO nanowalls grown on 4H-SiC by molecular beam epitaxy

2019 ◽  
Vol 52 (1) ◽  
pp. 168-170
Author(s):  
Mieczyslaw A. Pietrzyk ◽  
Aleksandra Wierzbicka ◽  
Marcin Stachowicz ◽  
Dawid Jarosz ◽  
Adrian Kozanecki
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Optoelectronic Devices ◽  
Growth Conditions ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fabrication And Characterization

Control of nanostructure growth is a prerequisite for the development of electronic and optoelectronic devices. This paper reports the growth conditions and structural properties of ZnMgO nanowalls grown on the Si face of 4H-SiC substrates by molecular beam epitaxy without catalysts and buffer layers. Images from scanning electron microscopy revealed that the ZnMgO nanowalls are arranged in parallel rows following the stripe morphology of the SiC surface, and their thickness is around 15 nm. The crystal quality of the structures was evaluated by X-ray diffraction measurements.

Study of Interface Properties of InN and InN-Based Heterostructures by Molecular Beam Epitaxy

2001 ◽  
Vol 693 ◽  
Author(s):  
Hai Lu ◽  
William J. Schaff ◽  
Lester F. Eastman ◽  
Colin Wood
Keyword(s):  
Molecular Beam Epitaxy ◽  
Film Thickness ◽  
Buffer Layer ◽  
Molecular Beam ◽  
Growth Conditions ◽  
High Energy ◽  
Near Surface ◽  
Low Leakage ◽  
Sheet Charge ◽  
Aln Buffer

AbstractIn this work, we prepared epitaxial InN on (0001) sapphire with an AlN or GaN buffer layer by molecular beam epitaxy (MBE). A series of samples were grown with different thickness under the optimized growth conditions. Films were characterized by x-ray diffraction (XRD), reflective high-energy electron diffraction (RHEED), atomic-force microscopy (AFM), transmission electron microscopy (TEM) and Hall measurements. By extrapolating the fitted curve of sheet carrier density vs. film thickness to zero film thickness, a strong residual sheet charge was derived, which may be located at the interface between the buffer layer and the InN film, or at the near-surface. It was found that for InN film on AlN buffer, the residual sheet charge is about 4.3×1013 cm-2, while for InN films on GaN buffer, the residual sheet charge is about 2.5×1013 cm-2. At present, we tentatively believe that the residual charge is surface charge accumulation similar to what is observed at the InAs surface. InN samples with Hall mobility beyond 1300 cm2/Vs and carrier concentration below 2×1018 cm-3 were routinely achieved in this study.The first study on InN-based FET structures was performed. Amorphous AlN was used as the barrier material, which was prepared by migration enhanced epitaxy (MEE) at low growth temperature. It was found that the surface morphology is improved after an AlN barrier layer is added to InN. Hg was used as a back-to-back Schottky metallization. Very low leakage current and weak rectifying behavior were observed.

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