bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth Properties of the Si(100) Steps: A Molecular Dynamics Study
Authors: Roland Christopher , Gilmer George H. 
Published: March 2011

ABSTRACTWe have mapped out the energy surfaces seen by a single silicon adatom over the Si(100) surface and Si(100) steps, using Molecular Dynamics methods. This identifies the most likely binding sites as well as the activation energies for diffusion over the terraces and steps. We find that only the 5e step with no rebonded atoms is a good sink for adatoms - the SA, rebonded Sb and Db steps are weak sinks. Because of a higher density of binding sites and lower activation energies for surface diffusion along die step edge, we expect mat growth at the Sb and Db steps take place much more readily man at the SA step.
Temperature-Dependent Evolution of Chemisorbed Digermane in Ge Thin Film Growth
Authors: Eres Djula , Sharp J. W. 
Published: March 2011

ABSTRACTThe formation and evolution of chemisorbed digermane layers in context with germanium thin film growth was investigated by time-resolved surface reflectometry. Modulation of the source gas supply made possible the separation and independent study of the temperature dependence of the adsorption and desorption processes. The regeneration of active sites by molecular hydrogen desorption was identified as the rate-limiting step at low substrate temperatures. A dynamic method of thin film growth was demonstrated by repetitively replenishing the active film growth sites regenerated between two successive source gas pulses. The film growth rate was shown to be related to the substrate temperature and the delay time between successive source gas pulses.
Grazing Incidence X-Ray Reflectometry Studies of Cadmium Arachidate Langmuir-Blodgett Films
Authors: Tanner B. K. , Bowen D. K , Petty M. C , Swaminathan S. , Granfeld F. 
Published: March 2011

ABSTRACTGrazing incidence X-ray reflectometry has been used to characterize Langmuir-Blodgett films of cadmium arachidate deposited on silicon substrates. The agreement between layer parameters deduced from the interference fringe period and low angle Bragg peak positions was excellent. Good agreement was found between experimental and simulated reflectivity profiles only when interface roughness and a varying molecular layer thickness was included. Inclusion of interface roughness alone results in a substantial enhancement in the intensity of the Bragg peaks. This effect is identified as being equivalent to the reduction in extinction found in classical X-ray diffraction due to crystal imperfections.
A Grazing Incidence X-Ray Diffraction Study of Self-Assembled Monolayers
Authors: Fenter P. , Li Jun , Eisenberger p. , Ramanarayanan T. A. , Liang K. S. 
Published: March 2011

ABSTRACTWe describe the two dimensional structure of n-Alkyl Thiols, CH3(CH217SH(C18, self-assembled on the surfaces of Au(111) and Ag(111). By using Grazing Incidence X-ray Diffraction (GIXD), we show that C18 forms ordered and dense monolayers. Although the properties of Au and Ag are very similar (for instance, the lattice constants of Au an Ag are nearly identical), the structure of C18on these two substrates is very different.
Electrochemical and Chemical Sulfidation of GaAs: A Surface Chemical Study
Authors: Yota J. , Burrows V. A. 
Published: March 2011

ABSTRACTTreatment of gallium arsenide with sulfur-containing media has been shown to improve GaAs surface electronic properties. However, there is still considerable controversy regarding the chemical nature of the surface film which results from the sulfidation, and of the basis of the electronic improvement and of the decay in the improved electronic properties with time. We have investigated the surface chemistry of the chemical sulfidation treatment of GaAs with Na2S-9H2O and the electrochemical sulfidation treatment of GaAs with Na2S-9H2O-ethylene glycol. Using surface infrared spectroscopy (SIRS), we have studied the film formed on the surface after the treatments and its behavior with time. Results show that the film on the GaAs surface contains sulfur which is often associated with oxygen, that this film slowly reacts in air to form unexpected species, e.g. sodium carbonate and sulfur-oxygen group-containing compounds, and that sulfur and oxygen are non-uniformly distributed.
Real-Time Studies of Interface Structural Dynamics
Authors: Lowe Walter P. , Clarke Roy 
Published: March 2011

ABSTRACTWe present dynamic structural studies of thin films and their interface with underlying substrates using real-time x-ray diffraction. Using synchrotron light we have observed, in real-time, interface dynamics in semiconductor systems such as GexSi(i−x)/Si. The measurements show that under large temperature changes thin epitaxial layers may behave cooperatively to modify the overall strain profile. Dynamic behavior is exhibited in a series of discontinuities in the perpendicular lattice constant of the overlayer.
Hydrogen Adsorption Effects on Thin Film Growth Mode Studied by Ion Scattering
Authors: ShojiK F. , Sumitomo K. , Kinoshita T. , Tanaka Y. , Oura K. , Katayama I. 
Published: March 2011

ABSTRACTThe effects of hydrogen adsorption on the growth process and structures of Ag thin films on Si(111)-7×7 surfaces has been studied. The growth process and film structures are investigated by low energy electron diffraction(LEED) and low energy ion scattering spectroscopy of time of flight mode(TOF-ICISS). The hydrogen adsorbed on the surface is investigated by low energy recoil detection analysis(TOF-ERDA). We have found that Ag thin films deposited onto hydrogen covered Si(111) surfaces grow with a mode definitely different from that on clean surfaces.
Change Of SI(111) Surface Reconstruction Under Noble Metal Films
Authors: Hong Hawoong , Aburano Richard , Lin D.-S. , Chiang T.-C. , Chen Haydn , Zschack P. , SPECHT E. D. 
Published: March 2011

ABSTRACTInterface structures between Si(111) and thick noble metal overlayers are studied by grazing-angle-incidence x-ray diffraction and crystal truncation rods. The 7×7 reconstruction is only preserved under a Ag film deposited at room temperature. This capped 7×7 structure changed to a 1×1 structure upon annealing over 250°C. A thick overlayer of room temperature deposited Au film destroyed the 7×7 reconstruction and changed the interface structure to 1×1. Our results are compared to a thick Cu/Si(111) interface structure1.
Profile Structures of Macromolecular Monolayers on Solid Substrates By X-Ray Interferometry/Holography
Authors: Kent Blasie J. , Xu Sontao , Murphy Margaret , Chupa Janine , McCauley John P. , Smith Amos B. , Petacolas Lawrence J. , Bean John C. 
Published: March 2011

ABSTRACTPrevious work has recently employed x-ray interferometry for the unique determination of the profile structures of ultrathin Langmuir-Blodgett multilayer films of Cd-arachidate and of tethered protein monolayers on the surface of Ge/Si multilayer substrates [1, 2]. These studies utilized the inorganic substrate as the reference structure for the interferometrie phasing of the meridional x-ray diffraction I (Qxy=0A-1, QZ) from the inorganic-organic composite structure. The substrates, fabricated by magnetron sputtering, contained only broad profile features (≥20 A), thereby limiting the spatial resolution of the organic profile structures so-determined. Molecular beam epitaxy (MBE) permits the fabrication of the multilayer reference structure with profile features as narrow as a single atomic monolayer, thereby providing delta-function-like features in the reference structure. The reference structure can then be tailored such that the autocorrelation function of the inorganic-organic composite profile structure [obtained by a Fourier transform of its meridional diffraction I (Qxy=0A-1, Qz) data without phase information] contains only the organic profile structure itself over a particular range of the profile coordinate z. This approach for uniquely determining the unknown profile structure of the organic overlayer is x-ray holography by analogy to simple off-axis holography with much longer wavelength radiation. We have initially utilized MBE fabricated Ge/Si multilayer substrates of the type N(Ge2Si30), e.g., for N=2 or 3 superlattice unit cells, each containing two Ge monolayers and thirty Si monolayers, to thereby determine the profile structures of four different organic overlayers, namely a) self-assembled alkylsiloxane monolayers, b) Langmuir-Blodgett cadmium alkylcarboxylate monolayers, c) a Langmuir-Blodgett Cd-arachidate head-to-head bilayer deposited on a)-above and, d) a covalently tethered protein monolayer.
Ion Channeling Study of Epitaxial Growth of α-Fe on H-Terminated Si (111) Surfaces
Authors: Karmarkar M. M. , Padmanabhan K. R. , Cheng Y.-T. , Chen Y. L. 
Published: March 2011

ABSTRACTEpitaxial α-Fe films deposited on H-terminated Si(111) surfaces by electron beam evaporation in ultra high vacuum were studied using ion channeling/Rutherford Backscattering spectrometry (RBS). A 700 Å thick Fe film deposited on a Si(1 11) substrate at room temperature has a surface minimum yield, χmin, of 22% at 2 MeV energy of 4He+ ions along Si <111>. A rapidly increasing yield in the aligned spectrum with the depdi of the film shows the presence of defects throughout the film. The sharp lower energy edge of the Fe signal indicates the absence of an amorphous region or a suicide layer at the interface. This establishes epitaxial growth of iron film on Si(111), a result supported by x-ray diffraction and transmission electron microscopy studies. A 700 Å thick iron film deposited at 300 °C shows a surface minimum yield of 12%. Ion channeling/ backscattering spectra of 1400 Å and 3000 Å thick Fe films deposited at 300 °C on Si(111) substrates show a χmin of about 3% for both films, indicating a substantial reduction in the defect density in the thicker Fe films. Etching of Si(111) substrates in either a 10% HF solution or a NH4F solution does not change the crystalline quality of the iron films significantly.
Surface Reconstructions of Strained Epitaxial CoSi2/Si(100) Layers Studied by Scanning Tunneling Microscopy.
Authors: Stalder R. , Schwarz C. , Sirringhaus H. , VON Känel H. 
Published: March 2011

ABSTRACTEpitaxial single-domain CoSi2(100) layers were grown on Si(100) by use of a template technique. In-situ scanning tunneling microscopy (STM) and reflection high energy electron diffraction (RHEED) were used for a detailed surface study. The (√2×√2)R45 reconstruction of the Co-rich “C-surface” and the (3√2×√2)R45 as well as a newly discovered (√2×√2)R45 of the Si-rich “S-surface” were resolved in real space and are discussed in detail. The transition from the C- to the S-surface above 500 °C is related to a (2×2) reconstruction.
A Novel Growth Method for High Quality GaAs/CaF2/Si(111) Structures by Using “Type-A” CaF2 Film
Authors: Mizukami H. , Ono A. , Tsutsui K. , Furukawa S. 
Published: March 2011

ABSTRACTControl of epitaxial relationship of CaF2 films grown on Si(111) substrates was considered to be important to improve surface morphology and crystallini ty of GaAs films on CaF2/Si(111) structures. We successfully grew CaF2 films with the “type-A” epitaxial relationship on Si(111) substrates, that is, the crystallographic orientation of the CaF2 films were aligned in the same direction as that of the Si(111) substrates. These “type-A” CaF2 films were grown by a two step growth method. It was found that surface morphology of GaAs films on the CaF2/Si(111) structures was drastically improved by growth of the “type-A” CaF2 films.
The Growth of Ni Overlayers on Au(100) Buffers Deposited on GaAs(100) and MgO(100) Substrates.
Authors: Gilles B. , Eymery J. , Marty A. , Joud J. C. , Chamberod A. 
Published: March 2011

ABSTRACTHigh quality single-crystal Au(100) buffers have been grown on GaAs(100) or MgO(100) substrates via a thin bcc Fe(100) nucleation layer. Using RHEED, LEED and Auger spectroscopy the growth of Ni overlayers at room temperature was observed to follow an epitaxial layer-by-layer mode for 2 monolayers, after which islanding occured. Detailed analysis of the Auger signal reveals that atomic mixing appears within the first completed layer. Grazing incidence diffraction has been used to investigate the structure of 5–10 nm films. A mixture of (100) and (110) grains have been characterized; the latter orientation shows a large number of stacking faults along the [111] direction in agreement with the Au[001] direction.
Epitaxial Growth of B-Doped SiGe Films Using Si-GeH4-B2H6 MBE
Authors: Kunii Yasuo 
Published: March 2011

ABSTRACTHigh-crystalline-quality B-doped SiGe films are epitaxial-ly grown on Si(100) substrates using the Si-GeH4-B2H6 MBE system. Both Ge and B profiles in the B-doped SiGe layer are readily controlled using the present system. This technique should be very promising in the bandgap engineering of SiGe base HBTs.
Selective Growth of GaAs on GaAs-Coated Si Substrate by Liquid Phase Electro-Epitaxy
Authors: Sakai Shiro , Ohashi Yasuno 
Published: March 2011

ABSTRACTThe selective LPEE (liquid phase electro-epitaxy) growth of GaAs on GaAs-coated Si substrate prepared by MOCVD has been performed. Several attempts, the use of the insulator melt cap, lowering of the melt height and optimization of the stripe direction, have been tried to increase the lateral growth rate. Very wide (60 μm) lateral overgrowth on the SiO2 mask is obtained by making the stripe window in <010> and equivalent directions and by increasing the lateral current component in the LPEE. The GaAs layer laterally grown on the SiO2 has much less EPD (etch pit density) showing that the defect in the MOCVD-GaAs is blocked by the SiO2. The growth mechanism and the method of increasing the lateral growth rate are discussed.
Solidification Interface Instabilities During Zone Melting Recrystallization Processing of Multilayer thin Film Structures
Authors: Yoon Sharon M. , Hess Christopher K. , Miaoulis Ioannis N. 
Published: March 2011

ABSTRACTThis paper describes a stability analysis of the solidification interface during graphite-strip zone-melting-recrystallization of Silicon-On-Insulator thin film structures. The study focused on instabilities induced by i) variations in the optical properties due to thickness perturbations in the structure and ii) changes in optical properties during phase change. Reflective and emissive interference effects between multilayers play a significant role in the temperature distributions during processing. The presence of a step perturbation imbedded within the film structure affects local heat absorption and resulting temperature profiles. Such disturbances that trigger instabilities at the solid-liquid interface were investigated numerically. Processing speeds which cause interface instability due to optical property variation during phase change were identified.
Numerical Transfer-Matrix Study Of Interfaces In Ising Models
Authors: Novotny M. A. , Richards H. L. , Rikvold P. A. 
Published: March 2011

ABSTRACTResults are reported for the surface tension, the surface free energy, the surface stiffness coefficient, and the single-step free energy for the Ising model in two and three dimensions. These are obtained by numerical transfer-matrix calculations, testing detailed predictions for the scaling of the largest eigenvalues of the transfer-matrix.
Thin-Film Reactive Interdiffusion in The TI-AL System
Authors: Maugis P. , Blaise G. , Philibert J. 
Published: March 2011

ABSTRACTWe have studied the thermodynamics and kinetics of growth of Al-Ti phases in thin-film interdiffusion couples, A lOOnm thick aluminum layer is vapor-deposited on a poly- or single-crystal titanium substrate, previously etched by ion bombardment. The sample is then annealed during a time ranging from a few minutes to a few hours, at temperatures from 300 to 600°C. The Al atomic fraction vs depth is determined using a sputtering technique, associated with thermo-ionization mass spectrometry (STIMS). At low temperature (300–450°C), titanium diffuses along the grain boundaries of the micro-crystalline aluminum layer, to form an Al-rich phase. At higher temperature (450–500°C), the T1AI3 phase grows rapidly up to the surface. Above 460°C, an intermediate Ti-72at/Al phase grows between TiAl3 and Ti‥ At 600°C, the aluminum layer becomes morphologically unstable.
The Growth Dynamics Of Solid 4He
Authors: Wang Chia-Lai , Agnolet Glenn 
Published: March 2011

ABSTRACTThe interfacial properties of the solid-liquid interface of 4He have been studied at temperatures below 0.5 K using crystallization waves. From the dispersion and damping of the crystallization waves, one can determine the interfacial stiffness, ᾶ, and the interfacial growth resistance, (Km)−1, respectively. Our measured values for ᾶ are consistently smaller than previously published values. At the lowest temperatures, the measured (Km)−1 increases as T4 which is consistent with the prediction that the growth velocity is limited by the scattering of ballistic phonons by the moving interface. We also observe that above 0.25 K the phonon damping is dramatically reduced.
Domain Growth and Wetting in a Low Molecular Weight Binary Fluid System
Authors: Shi Bill Q. , Cumming Andrew W. 
Published: March 2011

AbstractWe present the results of phase-separation experiments performed on the pseudo-binary fluid system guaiacol-glycerol-water. Elastic light scattering and optical microscopy were used to follow the phase-separation after quenches into the coexistence region of the phase diagram. For critical quenches, we observed the well known bicontinuous infinite cluster morphology normally associated with spinodal decomposition, but with two distinct growth modes. In the bulk, at early times we observed L(t) ∼ t1/3 consistent with diffusion driven dynamics, crossing over to L(t) ∼ t1 at later times, as hydrodynamics became important. Near the sample walls, there obtained a novel fast growth with L(t) ∼ t3/2, just as in the case of recent studies with polymer blends, inconsistent with either diffusion or interface driven dynamics. We attribute this large exponent to wetting effects, and the observation of the same phenomenon in such disparate systems as polymer blends and polar organic solvents is strong evidence that the phenomenon is generic to binary systems.
Dislocation Dissociation in the Σ13 Grain Boundary in Silicon
Authors: Sagalowicz Laurent , Beanland Richard , Clark William A. T. 
Published: March 2011

ABSTRACTTransmission electron microscopy has been used to study the atomic and dislocation structure of deformed and undeformed Σ13 {510} boundary in Si. It is shown that there are several alternative structures for this boundary, which may be separated by imperfect and partial grain boundary dislocations. It is also shown that the dissociation of crystal lattice dislocations which interact with the boundary during deformation results is far more complicated than simple geometrical models applicable in monatomic materials predicts.
High Resolution Analysis of Structure and Chemistry of Grain Boundaries in Silicon
Authors: Kim M. J. , Carpenter R. W. 
Published: March 2011

ABSTRACTHigh resolution electron microscopy and high spatial resolution analytical electron microscopy were used to analyze the structure and chemistry of a Σ3 {111} twin boundary in cast polysilicon and a Σ13 (510), [001] tilt boundary in a Si bicrystal. Twin boundaries in cast polysilicon were associated with lattice defects and discrete second phase precipitates. The precipitate was single phase amorphous and faceted on the Si {111} planes. Nanospectroscopy showed mem to be substoichiometric oxide. Similar oxide precipitates, but with different morphology, were also observed on the Σ13 tilt boundary in Si bicrystal, indicating that tilt grain boundaries and steps on twin boundaries were effective heterogeneous sites for nucleation of oxygen containing precipitates. The observed Σ13 tilt boundary exhibited a coincident site lattice periodicity but had an aperiodic interface dislocation core structure. Oxygen that diffused into the boundary in regions where precipitation did not occur may have played a role in modifying the GB core structures, resulting in aperiodicity. For both cases, a detailed analysis of grain boundary atomic structure and precipitate morphology is presented.
Combined Experimentaland Theoretical Determination of the Atomic Structure of the (310) Twin in NB
Authors: Campbells Geoffrey H. , King Wayne E. , Foiles Stephen M. , Gumbsch Peter , Rühle Manfred 
Published: March 2011

ABSTRACTA (310) twin boundary in Nb has been fabricated by diffusion bonding oriented single crystals and characterized using high resolution electron microscopy. Atomic structures for the boundary have been predicted using different interatomic potentials. Comparison of the theoretical models to the high resolution images has been performed through image simulation. On the basis of this comparison, one of the low energy structures predicted by theory can be ruled out.
Grain Boundary Structure and Morphology in 30° <100> Tricrystal Films of Al
Authors: Thangaraj N. , Dahmen U. 
Published: March 2011

ABSTRACTThe structure and morphology of 30° <100> tilt grain boundaries in tricrystal films of Al have been investigated by conventional and high resolution electron microscopy. By inducing heteroepitaxial growth on single crystal (111) Si substrates, Al formed polycrystalline thin films made of grains in three symmetry-related (100) orientations. The grain boundaries were well-faceted and a number of symmetric and asymmetric tilt boundaries and triple junctions were observed. Their morphology, topology and preferred faceting was related to the 12mm two-dimensional point symmetry of the tricrystal.
Study of Thermal Oxide Solid-State Reaction on GaAs Surfaces
Authors: Lu Z. , Chen D. , Osgood R. M. , Podlesnik D. V. 
Published: March 2011

ABSTRACTIn this paper, we will present a study of the thermal reaction of AsjOs with GaAs at temperatures below 550°C using monochromatic X-ray photoelectron spectroscopy (MXPS). A solid-state interface reaction of 4GaAs + 3AS2O5 → 2Ga2O3 + 3AS2O3 + 4As, which includes the usual native oxide thermal reaction: 2GaAs + AS2O3 → Ga2O3 + 4As, as well as a decomposition reaction AS2O5 → AS2O3 + O2 is responsible for the thermal reaction in this temperature range.
Phase Formation at Pd/Si1−xGex Interfaces
Authors: Buxbaum A. , Eizenberg M. , Raizman A. , Schäffler F. 
Published: March 2011

ABSTRACTIn this work we describe the interaction of Pd with Si1−xGex layers in terms of structure, composition and electrical properties. Strained epitaxial layers of Si1−xGex with x=0.09 and 0.18 were grown on Si (100) by Molecular Beam Epitaxy (MBE) at a growth temperature of 550°C, to a thickness of 3300Å and 2300Å, respectively, and then capped with a 100Å Si layer. At low temperatures (around 250°C), the formation of a ternary phase Pd2Si1−xGex along with small amounts of PdGe takes place. At high temperatures (around 550°C), the interaction is characterized by the formation of a double layered structure, where a Ge rich Si1−xGex region is formed between the Pd2Si1−xGex compound and the unreacted Si1−xGex. The high temperature treatment results in strain relaxation in the epilayer below the compound region. Electrical characterization of diodes formed from these layers clearly shows they are rectifying, with Schottky barrier heights around 0.65 eV.