PEMBE-Growth of Gallium Nitride on (0001) Sapphire: A comparison to MOCVD grown GaN

1996 ◽  
Vol 1 ◽  
Author(s):  
H. Angerer ◽  
O. Ambacher ◽  
R. Dimitrov ◽  
Th. Metzger ◽  
W. Rieger ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Growth Conditions ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
Force Microscopy ◽  
Atomic Force ◽  
Metalorganic Chemical Vapour Deposition

Thin films of GaN on c-plane sapphire were grown by plasma-enhanced molecular beam epitaxy (PEMBE). The influence of different growth conditions on the quality of the epitaxial layers was studied by x-ray diffraction (XRD), atomic force microscopy (AFM) and Hall measurements. For low deposition temperatures, the growth of a thin buffer layer of AlN results in a decrease of the XRD rocking curve full width at half maximum (FWHM) but also in poorer quality in electronic and optical properties. Samples of 3μm thickness with 570 arcsec FWHM in the XRD rocking curve, a near band gap PL-emission FWHM at 5 K of 7 meV, charge carrier densities of ne = 2 × 1017 cm−3, and Hall mobilities of 270 cm2/Vs at 300 K were grown without a buffer layer. A comparison of the morphology and XRD rocking curves with those of GaN films deposited by metalorganic chemical vapour deposition (MOCVD) shows that the two methods have different growth mechanisms.

Growth of Boron Carbide Nanostructures on Silicon Using Hot Filament Chemical Vapour Deposition

2018 ◽  
Vol 42 (2) ◽  
pp. 73-76 ◽  
Author(s):  
Azadeh Jafari ◽  
Mohammad Mosavat ◽  
Alireza Meidanchi ◽  
H. Hossienkhani
Keyword(s):  
Boron Carbide ◽  
Grain Boundaries ◽  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Boron Concentration ◽  
Chemical Vapour ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Hot Filament

Boron carbide nanostructures were grown on Si wafers through introduction of a mixture of B2O3 dissolved in methanol using hot filament chemical vapour deposition. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), Raman spectroscopy and the four-point probe technique were applied to characterise the properties of the boron carbide nanostructures. The XRD results showed that two kinds of boron carbide chemical compounds (B4C and B2C2) were deposited and the effect of boron concentration was significant. The FESEM images showed that the boron carbide nanostructures are made of crystal clusters with a cauliflower-like shape, in which the grain boundaries appear more clearly with increasing boron concentration. In addition, the AFM results showed that the surface roughness of the boron carbide films decreased with increasing boron concentration due to grain boundary diffusivity. The Raman spectrum results confirmed the presence of a B4C network and G and D bands. The results of the four-point probe method indicated that samples with higher boron incorporation showed the lowest sheet resistance (0.06 ω sq−1), which may be because of the decrease in inter-grain boundaries caused by the larger cluster size. This study suggests that higher boron incorporation in boron carbide nanostructures results in larger crystal clusters, higher thickness and lower film resistivity.

In as a Surfactant for the Growth of AlGaN/GaN Heterostructures by Plasma Assisted MBE

2002 ◽  
Vol 743 ◽  
Author(s):  
E. Monroy ◽  
N. Gogneau ◽  
E. Bellet-Amalnc ◽  
F. Enjalbert ◽  
J. Barjon ◽  
...  
Keyword(s):  
Molecular Beam ◽  
Growth Conditions ◽  
Molecular Beam Epitaxy Growth ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Dimensional Growth

ABSTRACTIn this paper, we study the surfactant capability of In for the growth of AlGaN/GaN heterostructures by plasma-assisted molecular beam epitaxy. Growth conditions were determined to have a self-regulated 1×1 In adlayer on AlxGa1-xN (0001). The presence of this In film favors two dimensional growth of AlGaN under stoichiometric conditions, and inhibits the formation of metal droplets on the surface. The quality of these layers was assessed by high resolution X-ray diffraction, atomic force microscopy and photoluminescence.

Surface Structure and Transport Properties of YBa2Cu3O7-δ Using La2/3Ca1/3MnO3 as Buffer

2003 ◽  
Vol 10 (02n03) ◽  
pp. 317-323 ◽  
Author(s):  
W. S. Tan ◽  
L. Yang ◽  
H. Sha ◽  
X. S. Wu ◽  
J. Gao ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Ultrathin Films ◽  
Rf Magnetron Sputtering ◽  
Epitaxial Films ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Out Of Plane

The YBa2Cu3O7-δ (YBCO) ultrathin films were prepared by off-axis rf magnetron sputtering on SrTiO3 (STO) substrate with a 300-Å-thick La2/3Ca1/3MnO3 (LCMO) buffer layer. At low temperature, the magnetism of the LCMO buffer layer seemed to be screened by the epitaxial YBCO layer with a thickness of more than about 125 Å. A remarkable magnetoresistance (MR) ratio was obtained for thinner YBCO cap layer. The superconducting transition temperature, Tc, decreases with decreasing YBCO thickness and disappears at the thickness of less than 85 Å. X-ray diffraction (XRD) was used to characterize the quality of the buffer and epitaxial films. The out-of-plane lattice parameters for both buffer and epitaxial layer varied monotonically. The surface structures of the buffer and the epitaxial YBCO films were characterized by atomic force microscopy (AFM). Interfacial diffusions for cations such as Y, Cu, La, Ca and Sr were deduced from Auger electron spectroscopy (AES). The larger diffusion length was found at the interface between YBCO and LCMO, which may relate to the suppression of superconductivity and magnetoresistance.

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.

Investigation Of Nucleation And Initial Stage Of Gan Growth By Atomic Force Microscopy And X-Ray Diffraction

1997 ◽  
Vol 482 ◽  
Author(s):  
P. W. Yip ◽  
S.-Q. Wang ◽  
A. J. Drehman ◽  
L. D. Zhu ◽  
P. E. Norris
Keyword(s):  
Atomic Force Microscopy ◽  
Surface Morphology ◽  
Deposition Temperature ◽  
Yellow Luminescence ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Initial Stage

AbstractThe nucleation and initial stage of GaN growth on sapphire was investigated by atomic force microscopy, X-ray diffraction and photoluminescence. A 15 to 30 nm thick GaN buffer layer deposited at proper conditions was extremely smooth and nearly amorphous. Proper post deposition annealing resulted in the buffer crystallized. The buffer layer deposition temperature, thickness and annealing time and temperature must be coordinated. Low deposition temperature and/or insufficient annealing of the buffer results in a GaN wafer which has fine spiking surface morphology with an RMS of 3.4 nm for 1.4 μm wafer, strong yellow luminescence and wide xray rocking curve FWHM. High deposition temperature, longer crystallization time, and a low growth rate results in a wafer which exhibits strong band edge luminescence without noticeable yellow luminescence, and a narrow (002) diffraction rocking curve. However, the surface morphology exhibits well developed hexagonal feature with RMS roughness of 14.3 nm for a 570 nm thick layer. X-ray rocking curve analysis revealed buffer crystallization, domain coalescence and alignment process. The FWHM of the ω–scan of GaN (101) diffraction was 1700–2000 arc seconds for 200–1400 nm wafers which indicates that the twist of the domains is not changing much with the growth.

Growth of (0001) ZnO Thin Films on Sapphire

1996 ◽  
Vol 449 ◽  
Author(s):  
A. J. Drehman ◽  
P. W. Yip
Keyword(s):  
Surface Roughness ◽  
Buffer Layers ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Axis Orientation ◽  
Force Microscopy ◽  
Sapphire Substrates ◽  
Atomic Force

ABSTRACTUsing reactive rf sputtering, we have grown (0001) oriented ZnO films in situ on heated c-axis sapphire substrates, that are promising, particularly in terms of surface roughness, as buffer layers for the subsequent epitaxial growth of III-V nitride films. We compare the effects of on-axis and off-axis sputter geometries on the film epitaxy and smoothness. We also examined the effect of substrate temperature on the growth and smoothness and quality of the film. X-ray diffraction was used to verify the hexagonal ZnO phase, its c-axis orientation and, qualitatively, the degree of its epitaxy. Atomic Force Microscopy (AFM) was used to determine the ZnO growth morphology and roughness. Our best films, obtained by off-axis sputter deposition, have a surface roughness of less than 1 nm.

Gallium Nitride Growth Using Diethylgallium Chloride as an Alternative Gallium Source

1998 ◽  
Vol 537 ◽  
Author(s):  
Ling Zhang ◽  
Rong Zhang ◽  
Marek P. Boleslawski ◽  
T.F. Kuech
Keyword(s):  
Growth Conditions ◽  
Rocking Curve ◽  
X Ray ◽  
Force Microscopy ◽  
Organic Vapor ◽  
Atomic Force ◽  
Curve Line ◽  
Metal Organic ◽  
Increasing Temperature ◽  
Trimethyl Gallium

AbstractMetal organic vapor phase epitaxy (MOVPE) of GaN has been carried out using diethyl gallium chloride (DEGaCI) and ammonia. The growth rate and efficiency of the DEGaCl-based growth decreases with increasing temperature when compared to trimethyl gallium (TMG)-based growth under similar conditions. Both low temperature buffer and the high temperature GaN layers were grown using the DEGaCI-NH3 precursor combination on the basal plane of sapphire and compared to similar structures grown using TMG and NH3. DEGaCl-based growth reveals an improved growth behavior under identical growth conditions to the conventional TMGa and ammonia growth. X-ray, Hall, and atomic force microscopy (AFM) measurements have been carried out on these samples providing a direct comparison of materials properties associated with these growth precursors. For the DEGaCl-based growth, the x-ray rocking curve line width, using the (0002) reflection, is as low as 300 arcsec on a 2.5-micron thick film. A RMS surface roughness of ∼0.5nm measured over a 10x10 micron area.

Examination of Titanium Oxides, Lead Oxides and Lead Titanates Using X-Ray Diffraction and Raman Spectroscopy

1993 ◽  
Vol 310 ◽  
Author(s):  
Lynnette D. Madsen ◽  
Louise Weaver
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Vapour Deposition ◽  
Mixed Oxides ◽  
Chemical Vapour ◽  
Titanium Oxides ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lead Oxides ◽  
Metalorganic Chemical Vapour Deposition

AbstractSingle oxides (with titanium or lead) deposited as thin films by low pressure metalorganic chemical vapour deposition were investigated by x-ray diffraction and Raman spectroscopy. Examination of mixed oxides (titanates) and silicates were also carried out using these techniques. The crystallographic nature of these thin films were examined and comparisons made to their bulk counterparts. The deposition and anneal conditions 600 for producing cubic PbTiO3 films are discussed briefly.

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.

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