bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Observations of the Redistribution of Implanted Nitrogen at the Si-SiO2 Interface During RTA Processing
Authors: Lysaght Patrick S. , Nguyen Billy , Bennett Joe , Williamson Gary , Torres Kenneth , Gilmer Mark , Luo Tien-Ying , Brady David , Guan Jay , Brown George A. , Zeitzoff Peter , Bersuker Gennadi , Mucha Jay , Geyling Franz , Gebara Gabriel , Vishnubhotla Lucky , Jackson Michael D. , Huff Howard R. 
Published: April 2011

ABSTRACTThe redistribution of nitrogen from silicon to the Si-SiO2 interface due to thermal processing is investigated by Secondary Ion Mass Spectroscopy (SIMS) using Metal-Oxide-Semiconductor (MOS) capacitors. SIMS profiles of implanted atomic nitrogen concentration indicate a significant redistribution of the nitrogen, from the silicon to the oxide layer in response to variations of the steady state time and temperature parameters of Rapid Thermal Anneal (RTA) processing. RTA treatment, in N2 ambient, over a temperature range of 750°C - 1100°C, results in a measured increase of the integrated nitrogen peak at the interface. High Frequency Capacitance Voltage (HFCV) measurements of an implanted (N/ 5 × 1014 cm2/s / 26keV) and annealed (900°C / 10s) sample is compared with a control (without N implant) sample to determine the relative nitrogen abundance at the interface. This value corresponds to the increase in fixed oxide charge Q that produces a negative shift in the flat band voltage Vo under negative gate bias conditions.
Decaborane as Ion Source Material for Boron Implantation
Authors: Sosnowski Marek , Gurudath Ravidath , Poate John , Mujsce Anthony , Jacobson Dale 
Published: April 2011

ABSTRACTFormation of p-type shallow junctions for future generations of Si technology will require ion implantation of B at very low energies, i.e. below 1 keV, where the beam formation and transport at reasonably high currents are hindered by Coulomb repulsion of ions at high volume density. An alternative to implantation of monomer ions at a very low energy is implantation of large molecular ions at a higher energy. In the latter case, the implantation depth of the atoms corresponds to a fraction of the beam energy, partitioned between the atoms of the molecule. The decaborane molecule (B10H14) is of particular interest for implantation of p-type shallow junction in Si, because each of the B atoms carries only 9% of the molecule's kinetic energy. Experimental PMOS devices made using decaborane implantation have been demonstrated recently. It also has been shown that transient enhanced diffusion (TED) of B in Si implanted with B ions and with decaborane ions at the equivalent dose and energy are the same. The prospect for using decaborane in ion sources is examined, based on measurements of its ionization and dissociation properties. It is shown that decaborane molecules are effectively ionized by electron impact in the energy range near 100 eV.
In Situ, Real-Time Studies of Film Growth Processes Using Ion Scattering and Direct Recoil Spectroscopy Techniques
Authors: Smentkowskiv V.S. , Krauss A. R. , Auciello O. , Im J. , Gruen D.M. , Holecek J. , Waters K. , Schultz J. A. 
Published: April 2011

ABSTRACTTime-of-flight ion scattering and recoil spectroscopy (TOF-ISARS) enables the characterization of the composition and structure of surfaces with 1–2 monolayer specificity. It will be shown that surface analysis is possible at ambient pressures greater than 3 mTorr using TOF-ISARS techniques; allowing for real-time, in situ studies of film growth processes. TOF-ISARS comprises three analytical techniques: ion scattering spectroscopy (ISS), which detects the backscattered primary ion beam; direct recoil spectroscopy (DRS), which detects the surface species recoiled into the forward scattering direction; and mass spectroscopy of recoiled ions (MSRI), which is a variant of DRS capable of isotopic resolution for all surface species - including H and He. The advantages and limitations of each of these techniques will be discussed.The use of the three TOF-ISARS methods for real-time, in situ film growth studies at high ambient pressures will be illustrated. It will be shown that MSRI analysis is possible during sputter deposition. It will be also be demonstrated that the analyzer used for MSRI can also be used for time of flight secondary ion mass spectroscopy (TOF-SIMS) under high vacuum conditions. The use of a single analyzer to perform the complimentary surface analytical techniques of MSRI and SIMS is unique. The dual functionality of the MSRI analyzer provides surface information not obtained when either MSRI or SIMS is used independently.
On the Diffusivity of Au in Pb
Authors: Campbell Ann N. , Turnbull David 
Published: April 2011

AbstractThe precipitation of Pb3Au from dilute Pb(Au) alloys and the subsequent Ostwald ripening of the precipitate phase have been studied. The Au diffusivity which limits the precipitation from Pb(500 at. ppm Au) specimens is in good agreement with Dp = 45 exp[(−20.8 kcal/mol)/RT], found previously to control the precipitation rate in Pb(900–1000 at. ppm Au) alloys (Rossolimo and Turnbull, 1973). In contrast, precipitation from Pb(100 at. ppm Au) alloys and Ostwald ripening in the Pb(500 at. ppm Au) specimens appear to be governed by the high temperature Au tracer diffusivity, DAu = 0.0041 exp[(−9.35 kcal/mol)/RT], which is about 103 times greater than Dp at the temperatures of interest, 75 to 112°C, and is attributed to the motion of a Au interstitial defect. In the 100 ppm alloys the Au is incorporated most easily at the ends of the Pb3Au crystals and a ribbon- or whisker-like morphology results. The particles which form at the grain boundaries in the 500 ppm Au alloy specimens are at least six times larger in volume than the matrix particles and ripen at their expense. The Ostwald ripening kinetics of the grain boundary particles scale with t1/2 rather than with t1/3 as is usual. The Pb3Au formed whiskers, blades, ribbons, or equiaxed particles depending upon the Au concentration and precipitation temperature. The precipitation and ripening kinetics are critically dependent on the morphology of the second phase.
Amorphous Ni-Zr Phase Formation in Self-Supporting Thin-Film Lateral-Diffusion Couples
Authors: Barbour J. C. , Mayer J. W. 
Published: April 2011

AbstractThe formation of an amorphous Ni-Zr alloy, by heating to cause interdiffusion in the temperature range 250°C to 325°C, was demonstrated in a self-supporting lateral-diffusion couple. Micro-area diffraction in a scanning transmission electron microscope (STEM) indicates that microcrystalline ordering in the amorphous phase must be on a scale less than 5 nm. The samples were heated in a vacuum furnace to form the amorphous phase and later heated in the STEM for in situ observation of crystalline compoundformation. The amorphous to crystalline transformation occurs first in theZr-rich regions at 370°C. A crystalline phase begins to consume the Ni rich amorphous material, at 450° C; but at 325° C, the amorphous phase is stable up to 20.5 hours, even in the presence of crystalline compounds.
Transformation Kinetics for Crystalline, Quasicrystalline, and Glassy Alloys in the Binary Al100-xMnx and Pseudobinary Al84-ySiyMn16Systems
Authors: Bagley B. G. , Chent H. S. 
Published: April 2011

AbstractThe condensed state phase transition energetics and kinetics are reported for specific compositions within the Al-Si-Mn system which demonstrate crystal → crystal, quasicrystal→ crystal, and glass.→crystal structural transformations. Our observations, and their interpretation, for the solid state crystalline AI(Mn)→Al+Al6 Mn reaction and the crystallization of glassy Al54Si 30Mn16 are consistent with the anticipated mode for these transformations. The nature of the quasicrystal→ crystal transformation, consistent with our observations, is an enigma.
Precipitation Kinetics in Metastable Solid Solutions – Theoretical Considerations and Application to Cu-Ti Alloys
Authors: Kampmann R. , Eckerlebe H. , Wagner R. 
Published: April 2011

AbstractCu-2.9 at.% Ti single crystals were homogenized at various temperatures (780 °C ≤ TH ≤ 960°C) and quenched. Subsequent isothermal aging at 350 °C led to phase separation, the kinetics of which have been followed by employing small-angle neutron scattering (SANS). According to comple-mentary transmission electron and analytical field ion microscopy studies, the resulting transformation products of this first order phase transition are stoichiometrically ordered ellipsoidal Cu4Ti particles, the aspect ratio of which changes with aging time (t) as revealed by two-dimensional SANS-detection. In the early stages of phase separation, the decomposition kinet-ics are strongly influenced by the quenching rate via quenched-in excess vacancies. During aging the structure factor S(K,t) develops a maximum, the height (Sm) of which increases and the position (Km) of which decreases with t. Neither Sm(t) nor Km(t) follow a power law as predicted by several recent theories on spinodal decomposition. On the other hand, the time evolution of the mean Ti-rich cluster size (R), their number density (Nv), and the supersaturation (Δc) as inferred from the SANS-data and the diffuse Laue-scattering, are well predicted by a precipitation model which describes nucleation, growth and coarsening as competing processes.
Superheating of Metallic Crystals
Authors: Däges J. , Gleiter H. , Perepezko J. H. 
Published: April 2011

AbstractFor crystals that melt into fluid liquids, superheating of the solid has been detected in only a few cases. In these cases, a crystal was subjected to focused heating in the center. Under a high thermal gradient some interior superheating was possible, but usually only a few degrees or less. A new approach is reported for preparing samples which can exhibit superheating under more uniform thermal conditions. To exclude the vapor from contact with the crystal a continuous coating is developed with a melting temperature in excess of that for the pure core crystal. For single crystal spherical Ag samples with a diameter of about 130 μm the free surface was coated with a continuous higher melting point layer of Au to inhibit surface initiated melting of silver at its melting point. The coated Ag crystals were observed to exhibit superheating of at least 7.5 K above the melting point of pure Ag for time periods of the order of one minute. Under the experimental conditions used, internal stresses could be excluded as the reason for the observed increase in the melting onset temperature of Ag. The superheating duration is related to the interdiffusion between the coating layer and the core crystal. Some microstructural observations and electron microprobe composition scans also relate to the observed superheating behavior. The results seem to disagree with lattice stability models of melting and may open the way to the study of crystals in the metastable superheated state.
Near-Field Optical Imaging of Electromigration Damages in Passivated Metal Stripes
Authors: Bonera E. , Borghesi A. , Caprile C. 
Published: April 2011

AbstractElectromigration is one of the main failure mechanisms limiting the miniaturization of microelectronic devices. As a consequence of the high current densities in the interconnections, hillocks and voids are formed and their evolution can modify the electrical performances of devices till failure. To characterize electromigration damages,. today's failure analysis techniques require removal of the protection passivation to allow scanning electron microscope or focused ion beam microscope imaging, but the removal process itself can damage the surface of the metal stripes. Due to the optical transparency of the passivation, near-field scanning optical microscopy can be used to overcome this problem. We succeeded in obtaining the first near-field images in resolution < 150 nm of electromigration-damaged metal structures without complete removal of the passivation. The latter was thinned to 100 – 200 nm to allow the evanescent waves to reach the metal structures and illuminate a subwavelength zone of the sample. Near-field images show the presence of hillocks and voids of dimensions down to 250 nm which can be due only to electrornigration, and, in this sense, they are more reliable than the usual scanning electron microscope images.
Fabrication and Characterization of 2D and 3D Ordered Arrays of Nanoparticles
Authors: Gates Byron , Zhong Ziyi , Xia Younan 
Published: April 2011

ABSTRACTTwo methods are presented which have been successfully used to fabricate highly ordered 2D and 3D arrays of nano-scale particles. The first method uses a combination of microcontact printing (μCP) and surface-templated reactions to form 2D patterned arrays of nanoparticles on silicon substrates. The second method uses confined self-assembly to crystallize colloidal particles into 3D cubic-close-packed (ccp) arrays (or opaline structures).
Lateral Transport through Self-Assembled InAs Quantum Dots Located in the Narrow Gap Electrodes
Authors: Jung S. K. , Hwang S. W. , Park J. H. , Min B. D. , Kim E. K. , Kim Yong 
Published: April 2011

ABSTRACTWe have fabricated and characterized the lateral electron transport through InAs quantum dots with double barrier system. Aluminum metal electrodes with the inter-electrode spacing of 30 nm have been deposited on an InAs self-assembled quantum dot wafer to form the planar type quantum dot devices. Current peak structure and negative differential resistance effects are observed above 77 K in current-voltage characteristics. These results are interpreted as due to 3D-0D resonant tunneling through the single quantum dot positioned in between the electrodes.
1.3 μm InAs/GaAs Quantum Dot Led
Authors: Childs D. , Malik S. , Siverns P. , Roberts C. , Murray R. 
Published: April 2011

ABSTRACTWe have determined the growth conditions which result in a narrow linewidth and room temperature emission at 1.3pm from InAs/GaAs Quantum dots (QDs). The QDs formed under these conditions are extremely uniform in size and exhibit an emission linewidth of only 25meV. Single QD layers have been incorporated into p-i-n diodes which exhibit strong electroluminescence. We have compared the efficiency of these devices with a nominally identical quantum well device. The QD based device exhibits a higher electroluminescence efficiency, especially at low current densities. At higher current densities there is a loss of efficiency due to recombination from excited states.Operated under reverse bias, the diodes act as photo-detectors and the measured photocurrent spectrum exhibits peaks due to absorption in the ground and excited states of the QDs as well as the 2D confining layer.
Properties of Ion Beam Synthesized Iron Disilicide Dots
Authors: Galli M. , Marabelli F. , Pagetti A. , Grimaldi M.G. , Coffay S. , Spinella C. , Miglio L. 
Published: April 2011

ABSTRACTSemiconducting iron silicide dots with dimensions ranging between 5 and 100 nm can be obtained by ion implantation on Si wafers and exhibit interesting photo- and electro- luminescent properties.In our study we use structural and optical characterization as well as theoretical modelling in order to: i) discriminate among intrinsic effects of FeSi2 dots and effects due to lattice damage and Si matrix; ii) identify the range of physical parameters (size, phase, electronic structure) corresponding to the luminescent dots.
Three Dimensional Finite Element Simulations of Vertical Dot Correlation in Quantum Dot Superlattice
Authors: Zhang Y.W. 
Published: April 2011

ABSTRACTA three dimensional finite element method is used to simulate the kinetic process of island formation in quantum dot superlattices. Depending on the thickness of spacer layers and interruption time, top layer islands can be fully vertically aligned with the same morphology as the buried islands, or can be partially vertically aligned with increasingly less uniform and regular arrangement, or can be alternately misaligned with increasingly uniform and regular arrangement.
Preparation and Optical Properties of Ge and C-Induced Ge Quantum Dots on Si
Authors: Eberl K. , Schmidt O. G. , Kienzle O. , Ernst F. 
Published: April 2011

ABSTRACTPure Ge epitaxially grown on Si (100) at high temperatures forms typically 100 nm lateral size islands on top of a 3–4 monolayer thick wetting layer. In stacked layers of Ge dots pronounced vertical alignment is observed if the thickness of the Si spacer layers is smaller than about 50 nm. Pregrowth of a small amount of C on Si substrate induces very small 10 nm size Ge quantum dots after deposition of about 2 to 3 monolayers Ge. Photoluminescence (PL) studies indicate a spatially indirect radiative recombination mechanism with the no-phonon line strongly dominating. Strong confinement shift in the 1–2 nm high and 1Onm lateral size dots results in low activation energies of 30 meV, which causes luminescence quenching above 50K.For large stacked Ge islands with 13 nm thin Si spacer layers we observe a significantly enhanced Ge dot-related PL signal up to room temperature at 1.55μm wave length. This is attributed to a spatially indirect transition between heavy holes confined within the compressively strained Ge dots and two-fold degenerated A state electrons in the tensile strained Si between the Ge stacked dots.
Preparation of Nanocrystalline Silicon Quantum Dots by Pulsed Plasma Processes with High Deposition Rates
Authors: Nishiguchi K. , Hara S. , Amano T. , Hatatani S. , Oda S. 
Published: April 2011

ABSTRACTA new method for the fabrication of nanocrystalline silicon (nc-Si) in SiH4plasma with very-highfrequency (VHF; 144MHz) excitation is proposed to increase the deposition rate, to control the size, and to minimize size dispersion of nc-Si. Nanocrystalline silicon is formed in the gas phase of the SiH4plasma cell by coalescence of radicals. Supplying Ar enhances the nucleation of nc-Si because of high efficiency of SiH4excitation into SiH2radicals resulting in the nucleation. The deposition rate is thus increased by a factor of 100 to 1012/cm2.h. At the low flow rate of SiH4, smaller nc-Si with small dispersion is obtained. Moreover, when pulsed-SiH4is supplied into Ar plasma, the growth of nuclei is limited by the time when SiH4flows. The size of nc-Si and its dispersion are adjusted by the duration of SiH4gas pulse.
Colloidal Synthesis and Properties of InAs/InP and InAs/CdSe Core/Shell Nanocrystals
Authors: Cao Yun-Wei , Aksenton Julia , Soloviev Victor , Banin Uri 
Published: April 2011

ABSTRACTHigh-temperature colloidal synthesis of InAs/InP and InAs/CdSe core/shell nanocrystal quantum dots is reported. InP and CdSe shells with several thicknesses were grown on InAs cores ranging in diameter between 20 to 50 Å. Optical spectra, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and X-ray diffraction (XRD) were used to analyze the core/shell quantum dots and determine their chemical composition, average size, size distributions, and structures. The experimental results indicate that shell growth is uniform, expitaxial, and controllable. For both InP and CdSe shells, growth is accompanied by a red shift of the band gap energy as a result of the extension of the electron wavefunction into the shell region. An increase of the room temperature photoluminescence quantum yield by a factor of∼4 is observed with CdSe shell growth on InAs Cores. The growth of InP shells, however, quenches the photoluminescence quantum yield. The difference is assigned to outer surface effects in core/shell nanocrystals.
Reservoir Layers in High Tc Mercury Cuprates
Authors: Geballe T. H. , Moyzhes Boris Y. , Dicktnson P. H. 
Published: April 2011

AbstractWe put forward the hypothesis that cations with 6s electrons (Hg,Tl,Pb,Bi) in the charge reservoir layers of high Tc cuprate superconductors actively participate in the pairing interaction as negative-U centers. We further argue that the Hg-cuprates are outstanding superconductors (Tc > 160 K) because they can exist as two-ion negative-U centers, . Their electrons are less localized than in single-site centers (negative-U or bipolaron) and can have a strong pairing interaction with a smaller increase in effective mass. The centers are oriented in the x and y directions and can have phase differences compatible with the d-wave symmetry of the CuO2 planes.
Mott Transition Field Effect Transistor: Experimental Results
Authors: Schrott A. G. , Misewich J. A. , Scott B. A. , Gupta A. , Newns D. M. , Abraham D. 
Published: April 2011

AbstractIn this paper we describe the fabrication of oxide based devices similar in architecture to a conventional FET with source, drain, and gate electrodes and a channel. This distinctive characteristic of our device is the use of a channel material capable of undergoing a field-induced Mott insulator-metal transition at room temperature. Lithographic techniques developed for oxide materials have been combined with pulsed laser deposition of perovskite materials onto single-crystal strontium titanate (STO) substrates to fabricate these devices. Materials chosen for the Mott transition channel include La2CuO4 (LCO) and YBCO, p-type; and Nd2CuO4, n-type.
Inspection and Manipulation of Ferroelectrics on the Nanometer Scale
Authors: Eng L. M. 
Published: April 2011

AbstractThe increasing interest in scanning probe instruments (SPM) stems from the outstanding possibilities in measuring electric, magnetic, optical, and structural properties of surfaces and surface layers down to the molecular and atomic scale. For the inspection of ferroelectric materials both the scanning force microscope (SFM) and the scanning near-field optical microscope (SNOM) are promising techniques revealing information on the polarization vector and the electric field induced stress within a crystal. Polarization sensitive modes are discussed as is friction force microscopy, dynamic force microscopy (DFM) and voltage modulated SFM. From these measurements, 180° domain walls (c-domains) are resolved down to 4 nm, while 3-dimensional polarization mapping in ferroelectric BaTiO3 ceramics reveals a 25 nm resolution. On the other hand, non-contact DFM measurements in ultra-high vacuum are able to resolve ferroelectric surfaces down to the atomic scale. Then also the chemical heterogeneity at the sample surface is differentiated from ferroelectric domains down to a 5 nm lateral resolution, taking advantage of the short range chemical forces. SNOM in contrast probes the optical properties of ferroelectric crystals both in transmission and reflection. Here image contrast arises from changes in the refractive index between different domains as well as at domain walls. In addition, SPM instruments are used for the local modification of ferroic samples by applying a relatively high voltage pulse to the SPM tip. Domains with diameters down to 30 nm are thus created with the size depending on both the switching and material parameters.
Correlated Magnetoexcitons in Semiconductor Quantum Dots at Finite Temperature
Authors: Dean D.J. , Strayer M.R. , Wells J.C. 
Published: April 2011

ABSTRACTWe describe computational methods for the theoretical study of explicit correlations beyond the mean field in excitons confined in semiconductor quantum dots in terms of the Auxiliary-Field Monte Carlo (AFMC) method [1]. Using AFMC, the many-body problem is formulated as a Feynman path integral at finite temperatures and evaluated to numerical precision. This approach is ideally suited for implementation on high-performance parallel computers. Our strategy is to generate a set of mean-field states via the Hartree-Fock method for use as a basis for the AFMC calculations. We present preliminary results.