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.

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.

Impact of Buffered Layer Growth Conditions on Grown-In Vacancy Concentrations in Molecular Beam Epitaxy Silicon Germanium

2004 ◽  
Vol 809 ◽  
Author(s):  
Kareem M. Shoukri ◽  
Yaser M. Haddara ◽  
Andrew P. Knights ◽  
Paul G. Coleman ◽  
Mohammad M. Rahman ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Buffer Layer ◽  
Point Defects ◽  
Growth Temperature ◽  
Silicon Germanium ◽  
Molecular Beam ◽  
Growth Conditions ◽  
Layer Growth ◽  
Vacancy Clusters ◽  
Temperature And Growth

ABSTRACTSilicon-Germanium (SiGe) has become increasingly attractive to semiconductor manufacturers over the last decade for use in high performance devices. In order to produce thin layers of device grade SiGe with low concentrations of point defects and well-controlled doping profiles, advanced growth and deposition techniques such as molecular beam epitaxy (MBE) are used. One of the key issues in modeling dopant diffusion during subsequent processing is the concentration of grown-in point defects. The incorporation of vacancy clusters and vacancy point defects in 200nm SiGe/Si layers grown by molecular beam epitaxy over different buffer layers has been observed using beam-based positron annihilation spectroscopy. Variables included the type of buffer layer, the growth temperature and growth rate for the buffer, and the growth temperature and growth rate for the top layer. Different growth conditions resulted in different relaxation amounts in the top layer, but in all samples the dislocation density was below 106 cm−2. Preliminary results indicate a correlation between the size, type and concentration of vacancy defects and the buffer layer growth temperature. At high buffer layer growth temperature of 500°C the vacancy point defect concentration is below the PAS detectable limit of approximately 1015 cm−3. As the buffer layer growth is decreased to a minimum value of 300°C, large vacancy clusters are observed in the buffered layer and vacancy point defects are observed in the SiGe film. These results are relevant to the role played by point defects grown-in at temperatures below ∼350°C in modeling dopant diffusion during processing.

scholarly journals Strain Effects on Optical Properties of (In,Ga)As-Capped InAs Quantum Dots Grown by Molecular Beam Epitaxy on GaAs (113)A Substrate

2011 ◽  
Vol 2011 ◽  
pp. 1-5
Author(s):  
Faouzi Saidi ◽  
Mouna Bennour ◽  
Lotfi Bouzaïene ◽  
Larbi Sfaxi ◽  
Hassen Maaref
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Growth Conditions ◽  
High Energy ◽  
Biaxial Strain ◽  
High Energy Electron ◽  
Inas Quantum Dots ◽  
Small Quantum

We have investigated the optical properties of InAs/GaAs (113)A quantum dots grown by molecular beam epitaxy (MBE) capped by (In,Ga)As. Reflection high-energy electron diffraction (RHEED) is used to investigate the formation process of InAs quantum dots (QDs). A broadening of the PL emission due to size distribution of the dots, when InAs dots are capped by GaAs, was observed. A separation between large and small quantum dots, when they are encapsulated by InGaAs, was shown due to hydrostatic and biaxial strain action on large and small dots grown under specifically growth conditions. The PL polarization measurements have shown that the small dots require an elongated form, but the large dots present a quasi-isotropic behavior.

Photovoltaic effect of ferroelectric Pb(Zr0.52,Ti0.48)O3 deposited on SrTiO3 buffered n-GaAs by laser molecular beam epitaxy

2017 ◽  
Vol 10 (04) ◽  
pp. 1750036 ◽  
Author(s):  
Yunxia Zhou ◽  
Jun Zhu ◽  
Xingpeng Liu ◽  
Zhipeng Wu
Keyword(s):  
Thin Film ◽  
Molecular Beam Epitaxy ◽  
Buffer Layer ◽  
Molecular Beam ◽  
Lattice Mismatch ◽  
Photovoltaic Effect ◽  
Short Circuit ◽  
High Energy ◽  
Text Type ◽  
Laser Molecular Beam Epitaxy

Ferroelectric Pb(Zr[Formula: see text],Ti[Formula: see text]O3(PZT) thin film was grown on [Formula: see text]-type GaAs (001) substrate with SrTiO3 (STO) buffer layer by laser molecular beam epitaxy (L-MBE). The epitaxial process of the STO was in situ monitored by reflection high-energy electron diffraction (RHEED). The crystallographical growth orientation relationship was revealed to be (002) [Formula: see text] PZT//(002) [Formula: see text] STO//(001) [Formula: see text] GaAs by RHEED and X-ray diffraction (XRD). It was found that a small lattice mismatch between PZT and GaAs with a 45[Formula: see text] in-plane rotation relationship can be formed by inserting of a buffer layer STO. Besides, the enhanced electrical properties of the heterostructure were obtained with the short-circuit photocurrent increased to 52[Formula: see text]mA/cm2 and the better power conversation efficiency increased by 20% under AM1.5[Formula: see text]G (100[Formula: see text]mW/cm[Formula: see text] illumination. The work could provide a way for the application of this kind of heterostructure with high photocurrent response in optoelectronic thin film devices.

Growth of Nonpolar (1100) Films and Heterostructures by Plasma-Assisted Molecular Beam Epitaxy

2004 ◽  
Vol 831 ◽  
Author(s):  
Oliver Brandt ◽  
Yue Jun Sun ◽  
Klaus H. Ploog
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Surface Segregation ◽  
Multiple Quantum Well ◽  
Growth Conditions ◽  
High Energy ◽  
Growth Direction ◽  
Desorption Kinetics ◽  
Multiple Quantum ◽  
Kinetics Of

ABSTRACTWe discuss the growth of M-plane GaN films and (In, Ga)N/GaN multiple quantum well (MQW) structures on LiAlO2(100) substrates by plasma-assisted molecular beam epitaxy. The adsorption and desorption kinetics of Ga on M-plane GaN is studied by reflection high-energy electron diffraction, allowing us to identify the optimum growth conditions with regard to surface morphology. Furthermore, we investigate the compositional profile of M-plane (In, Ga)N/GaN MQWs grown under conditions resulting in comparatively abrupt interfaces. The results demonstrate that significant In surface segregation occurs for the case of M-plane (In, Ga)N. The dependence of the transition energies of the M-plane MQWs on the actual well thickness reveals, however, that the structures are indeed free of electrostatic fields along the growth direction.

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.

Effect of Buffer Design on AlGaN/AlN/GaN Heterostrucutres by MBE

2003 ◽  
Vol 798 ◽  
Author(s):  
Gon Namkoong ◽  
W. Alan ◽  
A. S. Brown ◽  
M. Losurdo ◽  
M. M. Giangregorio ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Buffer Layer ◽  
Growth Conditions ◽  
Buffer Layers ◽  
Structural Quality ◽  
Epitaxial Layers ◽  
Etch Pit Density ◽  
Etch Pit ◽  
Sheet Charge ◽  
Aln Buffer

ABSTRACTThe effect of the buffer layers on the subsequent GaN epitaxial layers and electrical properties of AlGaN/AlN/GaN heterojunction structures nitrided at various temperatures was investigated. For AlN buffer layers, two different growth conditions of AlN buffer layers were introduced to avoid Al droplets. We found that etch pit density and structural quality of GaN epitaxial layer strongly depends on the growth conditions of AlN buffer layers. When using a double buffer layer (low temperature GaN on high temperature AlN) for 200 °C nitridation, the etch pit density was measured to high 107 cm-2 in GaN epitaxial layers. Furthermore, we observed that electrical properties of AlGaN/AlN/GaN heterostructures depend on growth conditions of buffer layers and nitridation temperatures. The mobility in Al0.33Ga0.67N/AlN/GaN structures grown on single AlN buffer layers for 200 °C nitridation were 1300 cm2/Vs at a sheet charge of 1.6×1013 cm-2. Using the double buffer layer for 200 °C nitridation, the mobility increased to 1587 cm2/Vs with a sheet charge of 1.25×1013 cm-2.

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 (<250°C).

Characterization of Al/GaAs Schottky barriers with thin Si interfacial layers

1993 ◽  
Vol 51 ◽  
pp. 800-801
Author(s):  
M.W. Bench ◽  
T.J. Miller ◽  
M.I. Nathan ◽  
C.B. Carter
Keyword(s):  
Molecular Beam Epitaxy ◽  
Barrier Height ◽  
Molecular Beam ◽  
Schottky Diodes ◽  
Growth Conditions ◽  
High Energy ◽  
Exact Nature ◽  
Interfacial Layers ◽  
Transmission Electron ◽  
Layer Structures

It has been shown in previous reports that barrier height variations can be achieved in GaAs Schottky diodes grown using molecular beam epitaxy by utilizing a thin epitaxial Si layer (a few monolayers) between the GaAs and the Al contact. The effective barrier height was found to be dependent on the thickness and growth conditions of the Si layer. However, there has remained a question as to the exact nature of the interfacial Si layer. In the present investigation, samples with different Si layer thicknesses (no Si, 6 Å Si, and 20 Å Si, as determined in situ during growth using reflection high energy electron diffraction (RHEED)) were characterized using transmission electron microscopy (TEM) to determine the nature of the Si layers. In the present study, it was also found that the presence of the interfacial Si layers affected the growth orientation and morphology of the Al layers.The layer structures investigated were grown using molecular beam epitaxy in a system described elsewhere.

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