High Tc YBa2Cu3O7−x Thin Films on GaAs-Based Substrate Using MgO Buffer Layers with Sb Passivation Technique 1

1992 ◽  
Vol 275 ◽  
Author(s):  
M. Z. Tseng ◽  
W. N. Jiang ◽  
E. L. Hu ◽  
U. K. Mishra
Keyword(s):  
Molecular Beam ◽  
Full Width Half Maximum ◽  
Ybco Film ◽  
Buffer Layers ◽  
Mbe Growth ◽  
High Tc ◽  
Rocking Curve ◽  
Molecular Beam Epitaxial ◽  
Wet Chemical

ABSTRACTHigh quality YBCO films have been grown on GaAs-based substrates via depositing MgO epitaxial buffer layers prior to YBCO growth. The critical temperature of the best YBCO film, Tc(0) was 87K and Jc>6.7×104 A/cm2 at 77K. The MgO buffer layers are usually [100] oriented along the normal of GaAs (100) substrates with full-width-half-maximum (FWHM) of rocking curve varying from 1–3 degree. We found that the uniformity and quality of MgO buffer layers are very sensitive to the pre-deposition preparation of GaAs-based substrates. Nonuniform MgO buffer layers are often obtained on those substrates prepared by wet chemical processing. Reproducible, controlled formation of the MgO buffer layer was achieved using an antimony passivation scheme, after molecular beam epitaxial (MBE) growth of the desired structure of the substrate.

MBE Growth of Ferroelectric YMnO3 Thin Films on Si(111) Using Y2O3 Buffer Layers

1998 ◽  
Vol 541 ◽  
Author(s):  
Shogo Imada ◽  
Shigeto Shouriki ◽  
Eisuke Tokumitsu ◽  
Hiroshi Ishiwara
Keyword(s):  
Thin Films ◽  
Molecular Beam ◽  
Ferroelectric Properties ◽  
High Energy ◽  
Buffer Layers ◽  
Mbe Growth ◽  
Rocking Curve ◽  
X Ray ◽  
Si Substrates

AbstractA ferroelectric YMnO3 thin films are grown on Si (111) substrates using Y2O3 buffer layers by molecular beam epitaxy (MBE). In-situ reflection high-energy electron diffraction (RHEED) analyses show that both Y2O3 and YMnO3 films are epitaxially grown on Si substrates. X-ray rocking curve measurements also show that the best FWHM (full width at half maximum) values for Y2O3 and YMnO3 films are 0.40° and 0.8°, respectively. C-V characteristics of Al/YMnO3/Y2O3/Si structures indicate the ferroelectric properties of YMnO3 films with a memory window of 0.7V.

Lattice Relaxation of AlN Buffer on Surface-Treated SiC in Molecular-Beam Epitaxy for Growth of High-Quality GaN

2002 ◽  
Vol 743 ◽  
Author(s):  
Jun Suda ◽  
Kouhei Miura ◽  
Misako Honaga ◽  
Norio Onojima ◽  
Yusuke Nishi ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Lattice Relaxation ◽  
Buffer Layers ◽  
Rocking Curve ◽  
X Ray ◽  
Hcl Gas ◽  
Aln Buffer ◽  
Atomically Flat

ABSTRACTThe effects of SiC surface treatment on the lattice relaxation of AlN buffer layers and the crystalline quality of GaN layers grown on the buffer layers were studied. AlN buffer layers and GaN main layers were grown by plasma-assisted molecular-beam epitaxy on on-axis 6H-SiC (0001)Si substrates. High-temperature HCl-gas etching resulted in an atomically flat SiC surface with (√3×√3)R30° surface reconstruction, while HCl-gas etching followed by HF chemical treatment resulted in an atomically flat surface with (1×1) structure. The AlN layer grown on the (1×1) surface showed slower lattice relaxation. GaN grown on the AlN buffer layer exhibited a (0002) X-ray rocking curve of 70 arcsec and 107 cm−2 of screw-type dislocation density, which was superior than that of GaN grown on (√3×√3)R30° surface.

scholarly journals Beating in the RHEED Intensity Oscillations during Surfactant Mediated GaAs Molecular Beam Epitaxy: Process Physics and Modeling

VLSI Design ◽  
1998 ◽  
Vol 6 (1-4) ◽  
pp. 405-408
Author(s):  
Vamsee K. Pamula ◽  
R. Venkat
Keyword(s):  
Molecular Beam ◽  
Flux Ratio ◽  
High Energy ◽  
Equation Model ◽  
High Energy Electron ◽  
Fixed Temperature ◽  
Mbe Growth ◽  
Molecular Beam Epitaxial ◽  
Monolayer Coverage ◽  
Period Of Oscillation

In a recent work, beating in the reflection high energy electron diffraction (RHEED) intensity oscillations were observed during molecular beam epitaxial (MBE) growth of GaAs with Sn as a surfactant. The strength of beating is found to be dependent on the Sn submonolayer coverage with strong beating observed for 0.4 monolayer coverage. For a fixed temperature and flux ratio (Ga to As), the period of oscillation decreases with increasing Sn coverage. In this work, we have developed a rate equation model of growth to investigate this phenomenon. In our model, the GaAs covered by the Sn is assumed to grow at a faster rate compared to the GaAs not covered by Sn. Assuming that the electron beams reflected from the Sn covered surface and the rest of the surface are incoherent, the results of the dependence of the RHEED oscillations on Sn submonolayer coverages for various Sn coverages were obtained and compared with experimental data and the agreement is good.

MBE Growth and Ultrahigh Temperature Processing of High-Quality AlN Films

1999 ◽  
Vol 587 ◽  
Author(s):  
Z.Y. Fan ◽  
G. Rong ◽  
N. Newman ◽  
David J. Smith ◽  
D. Chandrasekhar
Keyword(s):  
High Quality ◽  
Mbe Growth ◽  
Rocking Curve ◽  
Molecular Beam Epitaxial ◽  
Dislocation Densities ◽  
High Kinetic Energy ◽  
Nitrogen Ion ◽  
Ultrahigh Temperature ◽  
Molecular Beam Epitaxial Growth

AbstractMolecular beam epitaxial growth of AlN on sapphire and 6H-SiC has been performed utilizing mono-energetic activated nitrogen ion beams (2-80 eV kinetic energies). The growth temperature of AlN in MBE is found to be limited by the sticking coefficient of incident reactants. The combination of elevated growth temperatures (1050-1150°C), high kinetic-energy reactive nitrogen (>40 eV) and post-growth thermal processing (1150-1350°C) produces high-quality AlN thin-f ilms with narrow rocking curve widths (<2 arcmin) and low dislocation densities (<∼3×108cm−2). In contrast, the use of in-situ step anneals during synthesis did not achieve similar quality materials.

Kinetics of Ge Segregation in the Presence of Sb During Molecular Beam Epitaxy

1991 ◽  
Vol 220 ◽  
Author(s):  
S. Fukatsu ◽  
K. Fujita ◽  
H. Yaguchi ◽  
Y. Shiraki ◽  
R. Ito
Keyword(s):  
Molecular Beam Epitaxy ◽  
Epitaxial Growth ◽  
Lower Limit ◽  
Molecular Beam ◽  
Growth Direction ◽  
High Concentration ◽  
Mbe Growth ◽  
Molecular Beam Epitaxial ◽  
Molecular Beam Epitaxial Growth ◽  
Kinetics Of

Kinetics of Ge segregation during molecular beam epitaxial growth is described. It is shown that the Ge segregation is self-limited in Si epitaxial overlayers due to a high concentration effect when the Ge concentration exceeds 0.01 monolayer (ML). As a result, segregation profiles of Ge are found to decay non-exponentially in the growth direction. This unusual Ge segregation was found to be suppressed with an adlayer of strong segregant, Sb, during the kinetic MBE growth. We develop a novel scheme to realize sharp Si/Ge interfaces with strong segregante. Lower limit of the effective amount of Sb for this was found to be 0.75 ML.

Si-MBE SOI

1985 ◽  
Vol 53 ◽  
Author(s):  
T.L. Lin ◽  
S.C. Chen ◽  
K.L. Wang ◽  
S. Iyer
Keyword(s):  
Porous Silicon ◽  
Molecular Beam ◽  
Silicon On Insulator ◽  
Etch Pit Density ◽  
Mbe Growth ◽  
Molecular Beam Epitaxial ◽  
Etch Pit ◽  
Beam Method ◽  
Step Growth ◽  
Van Der Pauw

ABSTRACT100 μm-wide silicon-on-insulator (SOI) structures have been accomplished by utilizing silicon molecular beam epitaxial (Si-MBE) growth on porous silicon anid subsequent lateral-enhanced oxidation of porous silicon through pattern widows. A silicon beam method was used for insitu cleaning of Si surface at 750°C, and the effectiveness of this method was demonstrated by Auger electron spectroscopy and checked by the etch-pit density of the grown film. A two-step growth process of Si MBE was used to grow epitaxial layers of high quality. An electron mobility of 1300 cm2V-1s-1 was obtained by van der Pauw measurements.

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