bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Investigation of the Dislocation Structure of the NI/AG Phase Boundary
Authors: Bamford T.A. 
Published: March 2011

AbstractThe Ni/Ag interphase boundary structure in the parallel cube-on-cube orientation was studied for the boundary planes (001) and (011). Coarsely spaced dislocations were found in all annealed interfaces; the origin of these was apparently differential thermal expansion of the bicrystal film. A detailed search for intrinsic periodic structure consistent with the O-lattice construction was made using X-ray diffraction, electron diffraction and transmission electron microscopy . No evidence for this could be found; such a relaxation, if present, is very weak. It is unlikely that such a small relaxation could account for the relative energy minimum associated with the parallel cube-on-cube orientation found by previous investigators.
Formation and Structure of Thin Mo Layers and Mo-Ni Multilayers on Ni(001) by Molecular Beam Epitaxy
Authors: Lee Y.H. , Burns R.P. , Posthill J.B. , Bachmann K.J. 
Published: March 2011

AbstractThe growth of Mo overtayers and Mo-Ni multilayers on single crystal Ni(001) substrates is described. The nucleation and growth processes of these thin films were analyzed by LEED, XPS, AES and SEM and High Resolution AES investigations without breaking vacuum. Growth of Mo-Ni multilayer heterostructures on Ni(001) with ≈20Å periodicity is possible at low temperature (≈200 °C). At high temperature (≈550 °C) the growth proceeds by the Volmer-Weber mechanism preventing the deposition of small period multilayers. Annealing experiments on ultra-thin (<20Å) Mo overiayers deposited at 200 °C show an onset of interdiffusion at ≈ 550°C coupled to the generation of a new surface periodicity.
Effect of Substrate Misorientation on Heteroepitaxy with Large Lattice Mismatch: Ag/Si(111)
Authors: McKenna D.C. , Park K.-H. , Wang G.-C. , Smith G.A. 
Published: March 2011

AbstractEpitaxial films of Ag(111) were grown by Molecular Beam Epitaxy (MBE) on small angle misoriented Si(111) substrates. The surface normal was tilted 0 to 6° away from the Si(111) axis toward the [112] direction. The structure of the films was analyzed by x-ray diffraction and MeV He+ ion channeling. Despite a large lattice mismatch, good quality epitaxial films, 600–1200 Å thick, were grown on the misoriented Si substrates. Interestingly, the angle between the Si(111) axis of the substrate and the Ag(111) axis of the film (the misalignment angle) is not zero. In contrast to the perfect alignment on a flat substrate, the Ag(111) axis is tilted away from the Si(111) axis toward the surface normal. Axial MeV He+ ion channeling shows the misalignment angle (up to .6°) increases with substrate misorientation angle (~1/10 substrate misorientation angle).
Growth of Epitaxial CoSi2 and NiSi2 on (111), (100), and (110) Si at Room Temperature
Authors: Tung R. T. , Schrey F. 
Published: March 2011

AbstractGrowth of high quality type-B oriented NiSi2 and CoSi2 on Si(111) at room temperature was demonstrated recently. It is proposed that a few monolayers of metal reacts with Si(111) to form type B disilicide which then serves as a template for subsequent homoepitaxial growth during co-deposition. Thin, pre-annealed, silicide layers on Si (100) and (110) arc used as templates to demonstrate the homoepitaxial growth of NiSi2 and CoSi2 along these two directions at room temperature. The high temperatures usually required for the formation of NiSi2 and CoSi2 are related to the nucleation and mass transport processes.
Growth of Epitaxial IrSi3 Layers on Si(111)
Authors: Lin T. L. , Nieh C. W. 
Published: March 2011

AbstractEpitaxial IrSi3 films have been grown on Si (111) by molecular beam epitaxy (MBE) at temperatures ranging from 630 to 800 °C and by solid phase epitaxy (SPE) at 500 °C. Good surface morphology was observed for IrSi3 layers grown by MBE at temperatures below 680 °C, and an increasing tendency to form islands is noted in samples grown at higher temperatures. Transmission electron microscopy (TEM) analysis reveals that the IrSi3 layers grow epitaxially on Si(111) with three epitaxial modes depending on the growth conditions. For IrSi3 layers grown by MBE at 630 °C, two epitaxial modes were observed with ~ 50% area coverage for each mode. Single mode epitaxial growth was achieved at a higher MBE growth temperature, but with island formation in the IrSi3 layer. A template technique was used with MBE to improve the IrSi3 surface morphology at higher growth temperatures. Furthermore, single-crystal IrSi3 was grown on Si(111) at 500 °C by SPE, with annealing performed in-situ in a TEM chamber.
High Resolution X-Ray Scattering Studies of Strain in Epitaxial Thin Films of Yttrium Silicide Grown on Silicon(111)
Authors: Martinez-Miranda L. J. , Siegal M. P. , Heiney P. A. , Santiago-Aviles J. J. , Graham W. R. 
Published: March 2011

AbstractWe have used high resolution grazing incidence x-ray scattering (GIXS) to study the in-plane and out-of-plane structure of epitaxial YSi2-x films grown on Si (111), with thicknesses ranging from 85Å to 510Å. Our results indicate that the films are strained, and that film strain increases as a function of thickness, with lattice parameters varying from a = 3.846Å/c = 4.142Å for the 85Å film to a = 3.877Å/c = 4.121Å for the 510Å film. We correlate these results with an increase in pinhole areal coverage as a function of thickness. In addition, our measurements show no evidence for the existence of ordered silicon vacancies in the films.
Silicon Consumption During Self-Aligned Titanium Suicide Formation on Shallow Junctions
Authors: Smith P.L. , Osburn C.M. , Wen D.S. , McGuire G. 
Published: March 2011

AbstractThe self-aligned-silicide (SALICIDE) process was developed to overcome the conductivity and contact resistance limitations associated with very shallow junctions. However this process is fundamentally limited by the roughening and the consumption of the silicon substrate that occurs during its selective reaction with metal. As junctions scale to smaller dimensions, me silicon consumption must also be scaled so mat the suicide does not consume the junction. The use of argon gas atmospheres during titanium suicide formation leads to more silicon consumption (75%) than can be explained simply on the basis of suicide formation. Lateral loss of silicon into the metal surrounding patterns is believed to be the mechanism responsible for this excess silicon consumption. More surprisingly, nitrogen annealing, which suppresses lateral suicide formation, also leads to an anomalously large (50%) silicon consumption. Suicides formed on amorphous substrates during the concurrent formation of junctions and suicides result in even more silicon consumption.
Surface Morphologies and Interfaces of TiSi2 Formed from UHV Deposited Ti on Si
Authors: Jeon Hyeongtag , Nemanich R. J. , Honeycutt J.W. , Rozgonyi G. A. 
Published: March 2011

AbstractThe island formation of TiSi2 and the surface morphologies and interfaces of TiSi2 on Si have been examined and related to the surface and the interface energies. Ti (200Å and 400Å) films were deposited on clean, reconstructed Si(100) and Si(111) substrates at room temperature and also at high substrate temperatures (500°C~800°C). The TiSi2 formation process is monitored with in-situ LEED and AES and the surface morphologies and interfaces are examined with ex-situ SEM and TEM. For annealing to temperatures such that the C54 phase forms, the results indicate island formation with clean reconstructed substrate regions between the islands. The TiSi2 islands show different morphology on the (100) and (111) oriented substrates. The mechanism of TiSi2 island formation is described in terms of a liquid-liquid model, and the surface and interface energies for the TiSi2 island are determined from contact angle measurements.
Epitaxial Growth of Metallic Layers by Solid Phase Interdiffusion : Study of the Ni/GaAs and Ni/AlAs Systems
Authors: Guerin Roland , Deputier S. , Caulet J. , Minier M. , Poudoulec A. , Ballini Y. , Durel V. , Dupas G. , Guivarc’h A. 
Published: March 2011

AbstractAn ideal metal/III-V semiconductor contact should be made by stable and epitaxial metallic films. In principle, such a contact may be obtained by the solid state ΐnterdiffusion of a metal film with a III-V SC substrate. We studied the solid state interdiffusions in the Ni/GaAs and Ni/AlAs systems. Our starting point was the experimental determination of the Ni-Ga-As and Ni-Al-As ternary phase diagrams. The main steps of the interaction appear to be different in the two systems. During the Ni/GaAs one, three successive steps as a function of the annealing temperature are observed : first a mixture of a Ga-rich ternary phase (C phase) + NiAs, then C phase + NiAs + NiGa and at last the two binaries NiAs + NiGa where the reaction stops. In the case of the Ni/AlAs reactions, the three steps successively correspond to a mixture of NiAl + an As-rich ternary phase then NiAl + another As-rich ternary phase + NiAs and finally NiAl + NiAs. NiAs and NiAl are the key compounds in Ni/GaAs and Ni/AlAs reactions respectively and all the reaction compounds are either textured (pseudocubic NiAs and ternaries) or epitaxial (cubic binaries NiGa and NiAl).
Diffraction Studies of the Growth of Strained Epitaxial Layers
Authors: Whaley G.J. , Cohen P.I. 
Published: March 2011

AbstractThe molecular beam epitaxial growth of strained InGaAs films grown on GaAs(100) substrates has been studied using in situ reflection high-energy electron diffraction (RHEED). Both the intensity, shape and position of the diffracted beams were monitored during growth. Growth was found to be layer-by-layer up to a strain dependent thickness, at which point three-dimensional clusters were formed. These clusters exhibited (114) facets and were elongated in the [011] direction. The onset of 3D cluster formation was simultaneous with measurable lattice relaxation. The relaxation was determined using electromagnetic deflection of the RHEED pattern across two detectors. With this arrangement, the lattice constant could be measured to within 0.003Å. The onset could be delayed by lowering the growth temperature. For misfit strain greater than about 2%, the onset occurs at thicknesses less than the Matthews-Blakeslee critical thickness. For smaller strains, the onset occurs at larger thicknesses.
InAs and InGaAs Growth by Chloride Atomic Layer Epitaxy
Authors: Shimawaki H. , Kato Y. , Usui A. 
Published: March 2011

AbstractInAs chloride ALE has been carried out in detail, resulting in successful InGaAs ALE on (111)B InP substrates. InAs growth of 0.9 ML/cycle is obtained for (111)B InAs substrates at temperatures below 375 °C, while growth rates for (100) and (111)A substrates steadily decrease with increases in growth temperature. The growth rates are independent of InCI pressure at 375 °C, suggesting a self-limiting growth factor in InAs chloride ALE. (GaAs)1(InAs)1 and (GaAs)2(InAs)2 superalloys can be prepared on (111)B InP substrates at 375 °C. Growth rates and crystal compositions for both layers agree well with the values expected for ideal superalloys. The presence of superlattice structures is indicated by X-ray diffraction measurement,
Trimethylgallium Decomposition on a Heated Si(100) Substrate
Authors: Gow T.R. , Lin R. , Masel R.I. 
Published: March 2011

AbstractTrimethylgallium (TMGa) is an important source gas for metal-organic chemical vapor deposition (MOCVD) and metal-organic molecular beam epitaxy (MOMBE). In the last three years, workers in three different laboratories have examined the pyrolysis of trimethylgallium (TMGa) on heated substrates. However, the mechanism of the decomposition process is still not understood. In this paper we consider the mechanism of the TMGa decomposition on a hot Si(100) substrate in a molecular beam system. It is found that at TMGa doses of 1×1015 molecules/cm2 or less, the decomposition process in the beam system is the same as that reported by Lee et al., Surface Sci. 216, 173 (1989) in studies where TMGa was dosed at low temperature and then the substrate was heated. However, at higher TMGa doses, the mechanism in the molecular beam system is different than the ones reported previously. It is possible to transiently populate a weakly bound state which we assign to TMGa adsorption in the second monolayer. If me sample is below 400 K, the TMGa in the second monolayer desorbs. However, at higher temperatures, the TMGa in the second monolayer can react to form a CHx group (x=3 or 4) and dimethylgallium. The dimethylgallium desorbs. However, some of the CHx groups remain bound to the substrate leading to extra carbon incorporation. There also is evidence for formation of traces of monomethylgallium above 500 K and an indication of methyl radical desorption above 650 K. Thus it seems that at high doses, the decomposition of TMGa on a hot substrate is somewhat different than the decomposition of a monolayer of TMGa which has been adsorbed at low temperatures and then heated. These results explain some of the apparent discrepancies in the literature.
Effect of Stoichiometry on the Activation of Implanted Si in MBE-grown GaAs on Si
Authors: Kim T.S. , Kao Y.C. 
Published: March 2011

AbstractIn this work, activation of Si implanted into GaAs-on-Si layers grown by molecular beam epitaxy (MBE) is studied. We have found that activation efficiency of implanted Si is lower in GaAs on Si than in bulk GaAs and varies widely. By studying the activation of non-amphoteric dopants such as Be and S, we have found that no donor- or acceptor-like defects exist in high concentrations in GaAs on Si and that amphoteric behavior of Si is the major compensation mechanism in MBE-grown GaAs on Si. Increased Si-acceptor concentration and S activation in GaAs on Si are apparently due to a high density of As vacancies which result from a low V(As):III(Ga) flux ratio during growth. The effect of the threading dislocations does not appear to be significant compared to that of As vacancies as no correlation is found between the density of threading dislocations and implanted Si activation.
MBE Grown GaAs on Si(100) Studied by Infrared Spectroscopy
Authors: Eickhoff T. , Morley S. , Zahn D.R.T. , Richter W. , Woolf D.A. , Westwood D.I. , Williams R.H. 
Published: March 2011

AbstractGaAs layers were deposited onto Si(100) substrates using molecular beam epitaxy (MBE). The substrates were prepared by various methods before the growth of 0.1µm thick GaAs buffer layers. Active GaAs layers were thereafter grown with thicknesses from 1 to 4µm. Infrared spectra were recorded in the spectral ranges from 12 to 65cm-4 and 50 to 500cm-1 of the thin buffer layers as well as the thick active layers. The infrared active phonon of GaAs already shows up in the spectra for the 0.1µm buffer layers. The phonon parameters were derived from a harmonic oscillator fit to the experimental data. The phonon damping constant is correlated with the bulk quality of the GaAs layers. These results are compared with those obtained from Raman and spectroscopic ellipsometry measurements.
A New Oxygen Plasma Source for In-Situ Thin Films Growth of DY1BA2CU3O7-x by Molecular Beam Epitaxy
Authors: Touzeau M. , Schuhl A. , Cabanel R. , Luzeau P. , Barski A. , Pagnon D. , Hirtz J.P. , Creuzet G. 
Published: March 2011

AbstractWe describe an atomic oxygen source based on a D.C. plasma discharge, compatible with cristal growth in a Molecular Beam Epitaxy(M.B.E.) system. The physical characteristics of the oxygen cell are presented. The efficiency of the cell has been proved by direct deposition of CuO at high temperature(500°C). Moreover, we used successfully this cell for direct epitaxial growth of high temperature superconductors, with an ambient pressure as low as 2 10-5 Torr.
Dependence of Mo/Si Multilayer Morphology on Deposition Angle
Authors: Cheng Yuanda , Beth Stearns Mary , Smith David J. 
Published: March 2011

AbstractStudies have been made of the dependence of the structure on the deposition angle and the substrate temperature of a series of Mo/Si multilyers fabricated in a UHV system by e-beam evaporation. The detailed morphology was determined by cross-sectional high resolution electron microscopy. Columnar growth in the crystalline Mo layers was found to follow the tangent rule. The overall quality of the multilayers was found to depend strongly on the growth conditions.
Reduction of Defect Density in Heteroepitaxial GexSi1-x Grown on Patterned Si Substrates
Authors: Fitzgerald E.A. , Xie Y.-H. , Michel J. , Freeland P.E. , Weir B.E. 
Published: March 2011

AbstractWe have investigated the molecular beam epitaxial growth of GexSi1-x on small growth areas patterned in Si substrates. Electron beam induced current, etch-pit density measurements, transmission electron microscopy, and photoluminescence were used to compare dislocation densities in GexSi1-x on patterned and unpattemed substrates. We find a dramatic reduction in both misfit and threading dislocation densities for the patterned substrate growth. Our results also show that dislocation introduction is dominated by heterogeneous nucleation.
An Introduction to Wavefunction Engineering
Authors: Pearsall T.P. 
Published: March 2011

AbstractExperimental and theoretical studies demonstrate that it is possible to redefine the basic character of band-edge electronic wavefunctions in superlattices, the period of which is comparable to the lattice parameter of the constituent materials. In using superlattice periodicity to redefine electronic wavefunctions, strain and crystalline orientation can be used to select which wavefunctions will form the band edge states. These principles can be used to form a direct bandgap semiconductor superlattice from Si and Ge, two indirect bandgap materials.
Photoluminescence from Si/Ge Superlattices
Authors: van de Walle G.F.A. , Montie E.A. , Gravesteijn D.J. , Fredriksz C.W. 
Published: March 2011

AbstractThe luminescence of short period Si/Ge superlattices was systematically studied as a function of composition, strain and superlattice period. With Rutherford backscattering spectrometry the composition was determined, while X-ray diffraction was used to determine the strain and superlattice period. Two luminescence bands around 1,6 µm were observed. Etching experiments showed that the signal originated from the superlattice. Changes in wavelength and intensity were found to be related to the composition and the strain, while no clear influence of the superlattice period was observed.
Characterization of Undoped Pseudomorphic InGaAs/GaAs Quantum Wells by Electron Beam Electroreflectance (EBER) and Photoluminescence (PL)
Authors: Herman M. H. , Dodabalafur A. , Ward I. D. , Streetman B. G. 
Published: March 2011

AbstractWe have investigated the interband optical transitions within undoped pseudomorphic InyGa1-yAs/GaAs quantum wells of a range of thickness from 50Å to 150Å, and y values 0.1 to 0.2. From photoluminescence (PL), we identify the lowest interband transitions. Electron beam electroreflectance (EBER) modulation spectroscopy is utilized to detect the lowest and the higher energy interband transitions within the quantum wells. We compare the measured interband energies to those calculated theoretically.We have observed exciton-like transitions attributable to the heavy hole and light hole levels and most importantly, confined states of the split-off valence band, not reported to date. The multiplicity of observed quantum transitions allows rectangular barrier model parametrization of these wells, using hypothetical strain splitting of the various subbands. For five such quantum wells, we find the estimated indium contents and well widths to be nearly nominal, with consistent values between independent 300K and 100K data. With respect to the heavy hole subband, the conduction band offset Qc is estimated to be 0.586 ±0.024. With suitable values, all of the transitions, including those of the splitoff band, are predicted accurately.
Magneto-Optical Studies of 2-D Electrons in GaAs-AlGaAs Single Heterojunctions
Authors: Lee K-S. , Perry C.H. , Worlock J.M. 
Published: March 2011

AbstractWe report low temperature magneto-photoluminescence(PL) investigations of ex-citon spectra of n-doped (AlGa)As-GaAs single heterojunctions. At zero field, the PL spectrum is dominated by the free excitons and excitons bound to the impurities in the bulk GaAs, which overlap a weak emission band associated with the radiative transition between the two dimensional electron gas(2DEG) and the photoexcited holes. In the presence of a magnetic field applied parallel to the growth axis the transitions from the 2DEG, now quantized into Landau levels, become well pronounced. Additionally, intensity oscillations are observed when the 2DEG line crosses the exciton lines, which we believe is due to the effect of a resonant tunneling of the 2DEG from the quantum well region to the bulk GaAs.
Raman Scattering from an Interfacial Thin Layer of GaAs Heteroepitaxially Grown on Silicon (100) Substrate
Authors: Akagi Yoshiro , Ishino Mariko , Nakajima Yoshiharu 
Published: March 2011

AbstractIn an epi-layer of GaAs less than 300nm to 100nm thick grown on silicon substrate by two-step MOCVD lethod, broad Raman scattering centered at 700cm-1(L+) and TO-like phonon at 268cm-1(L-1) were observed as well as LO phonon spectrum (292cm -1) in a back-scattering optical geometry. Emission peak of photoluminescence spectra in these epilayer of GaAs were found to shift by 33meV at 300K towards high energy side. In a thin buffer layer of GaAs less than 20nm thick, however, Raman spectra showed only LO phonon peak. These experimental facts shows n-carrier generation of 1018cm-3 only within interfacial epi-layer of GaAs less than 300nm thick, except for the very thin buffer layer of GaAs, because of incorporation of silicon atoms during growth of epilayer at 700°C. In addition, in both layers of GaAs less than 300nm, compressive stress of 109dyn·cm-2 was observed, which were found to relax abruptly with thickness.
Raman Characterization of InSb/GaAs Grown by Metalorganic Magnetron Sputtering
Authors: Feng Z. C. , Perkowitz S. , Rao T. S. , Webb J. B. 
Published: March 2011

AbstractThe new technique of metalorganic magnetron sputtering (MOMS) produces high-quality (100) epitaxial InSb films on (100) GaAs substrates, despite the large 14.6% lattice mismatch between InSb and GaAs. We have used Raman scattering to examine MOMS-grown InSb films of thicknesses 0.17 - 2.67 µm, and commercial bulk InSb. We observe the longitudinal optical (LO) phonon peak, and the second order 2LO peak, which is enhanced by outgoing resonance with the E1 + Δ1, gap of InSb. The half-widths and intensities of these bands are related to sample quality as a function of film thickness and to the role of biaxial stress in the InSb film.
High Pressure Optical Studies of GaSb-AlSb Multiple Quantum Wells
Authors: Rockwell Benjamin , Chandrasekhar H.R. , Chandrasekhar Meera , Pollak Fred H. , Shen H. , Chang L.L. , Wang W.I. , Esaki L. 
Published: March 2011

AbstractThe pressure coefficients (α) of the excitonic transitions arising from the conduction (CB) to the heavy (HH) and light (LH) hole sub-bands of a GaSb-AlSb multiple quantum well structure (MQW) grown on a GaAs substrate are determined. Photoreflectance (PR) and Photoluminescence (PL) studies are employed at cryogenic temperatures. The α for the ground sub-band transition is ~10% smaller than that for bulk GaSb. This effect is explained by in-plane deformation of the MQW arising from the substrate under external pressure. On the other hand, the α get progressively smaller for the higher sub-band transitions due to quantum confinement The PL intensity drops dramatically as the direct Γ CB crosses the L CB at ~10kBars but the PR intensity persists until the X CB crosses each sub-band energy.