bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sub-Nanometric Resolution Depth Profiling of Ultrathin Ono Structures
Authors: Radtke C. , Salgado T.D.M. , Krug C. , Andrade J. de , Baumvol I.J.R. 
Published: April 2011

ABSTRACTUltrathin silicon oxide/nitride/oxide films on silicon prepared by the usual route -thermal growth of an oxide followed by deposition of a nitride layer by chemical vapor deposition, and finally a reoxidation step - were characterized using isotopic substitution of N and O and depth profiling with sub-nanometric resolution. The redistribution of N and O during the oxide/nitride/oxide film processing was investigated by: i) 15N and 18O depth profiling by means of narrow nuclear resonance, and ii) 16O profiling using step-by-step chemical dissolution associated with areal densities determinations by nuclear reaction analysis. It was observed that the reoxidation step, here performed varying temperature and time, induces atomic transport of O and N thus resulting in oxide/nitride/oxide structures which are not stacked layered ones, but rather silicon oxynitride ultrathin films, in which the N concentration presents a maximum in the bulk and is moderate in the near-surface and near-interface regions.
Process Definition for Obtaining Ultra-Thin Silicon Oxides Using Full-Wafer Electrical and Optical Measurements
Authors: Oberhofer A. , Chen J. , Koh K. , Schrader M. , Shah S. , Venables R. , Young C. , Xu M. , Kuehn R. , Maher D. , Venables D. 
Published: April 2011

ABSTRACTThe objective of this research was to establish a new baseline process for obtaining ultra-thin silicon-oxide gate material in a prototype vertical furnace. Of particular concern was the optimization of a process sequence whereby unpatterned 150 mm diameter wafers ‘see’ the same processing steps prior to gate oxidation as patterned device wafers ‘see’. The figures-of-merit for evaluating process optimization include: i) full-wafer current-voltage (I-V) maps using Hg-gate capacitors; ii) the variation in the current or current density at a given bias voltage, extracted from an I-V map; iii) the variation in electrical oxide thickness that is extracted from full-wafer capacitance-voltage measurements using Hg-gate capacitors; and iv) the variation in optical oxide thickness that is extracted from full-wafer spectroscopic ellipsometry measurements. The results from this research demonstrate that: i) the addition of 1% O2 to the usual N2 gas during the ramp-up cycle in the vertical furnace is necessary to achieve acceptable across-the-wafer oxide-thickness uniformity as determined from both electrical and optical figures-of-merit; and ii) a full-wafer response surface of the current at a given bias voltage is a powerful finger print for process development when the question of variation in as-grown silicon-oxide thickness is at issue.
Modeling of {311} Defects
Authors: Hobler G. , Rafferty C.S. 
Published: April 2011

ABSTRACTAn improved model of {311} defect evolution is developed based on the rate equations approach. A new expression for the reaction rate constant is presented that is based on the assumption that interstitials may react with the {311} defects along their whole surface. The energetics of {311} defects is treated by calculating the strain energy within the framework of the theory of dislocations in isotropic continua. Using the core energy of the atoms in the defects as the only fit parameter, we explain a wide range of experimental data. Furthermore, we apply the model to investigate closure assumptions used in moments models and propose a new two-moments model that uses the rate equations solver as a pre-processor.
Transient Enhanced Diffusion and Dose Loss of Indium in Silicon
Authors: Dokumaci Omer , Ronsheim Paul , D'emic Christopher , Domenicucci Anthony G. , Hegde Suri , Kozlowski Paul , Wong H.-S. Philip 
Published: April 2011

ABSTRACTThe dose loss and transient enhanced diffusion of indium in silicon were studied as a function of dose. Indium was implanted into silicon through a 90 A oxide at 50 keV for doses ranging from 3x 1012 to 2x14 cm−2. These conditions provide peak concentrations that approximately range from 1x1018-1x1020 cm−3. After an RTA anneal at 1000°C for 5s, indium exhibits substantial motion at both the tail and peak regions for high doses. The enhanced diffusion is mostly over within 5s. There was not any observable enhanced diffusion in the tail region at the lowest dose although there was significant movement at the peak region. The dose loss correlates very well with the enhancement in the diffusivity. TEM images show that the amorphization dose lies between 3x1013 and 8x1013 cm−2. In spite of the amorphization, diffusion enhancement in the tail region still keeps increasing with dose, which is contrary to a model of “+1” interstitials and complete removal of interstitials in the regrown layer. The 550°C lh anneals show that the dose loss can partially be attributed to the sweeping of the dopant by the growing a/c interface. Previously, the solubility of indium has been estimated to be around 1–2×1018 cm−3. At high doses, significant movement is observed at the peak of the indium profile although the peak concentration exceeds the solubility level by at least an order of magnitude. This shows that indium is not precipitating into an immobile phase like antimony or boron.
Relative Stability of Perfect and Faulted Dislocation Loops in Silicon
Authors: Omri M. , de Mauduit B. , Claverie A. 
Published: April 2011

ABSTRACTWe have studied by TEM the thermal evolution of a population of extrinsic defects composed of a mixture of both perfect and faulted dislocation loops (PDL's and FDL's respectively). It is shown that, when isolated from an external sink, the FDL's trap the Si interstitial atoms emitted by PDL's. When a highly recombining surface is located close to the defects, it preferably « pumps » the PDL's. On the contrary, injecting Si(int)'s from the surface helps stabilizing the PDL's while the FDL's grow. These experiments clearly show that FDL's are more stable, i.e. have higher binding energies than PDL's.
Two-dimensional Dopant Diffusion Study using Scanning Capacitance Microscopy
Authors: Yu Guanyuan M. , Griffin Peter B. , Plummer James D. 
Published: April 2011

ABSTRACTThe results of a two-dimensional dopant diffusion study using two new sample preparation techniques and a database-driven deconvolution technique are presented. These techniques are applied to real devices to justify complex implantation and diffusion models. It will be shown that the dose loss behavior is not uniform along the silicon/oxide interface from the source/drain region to the channel region. A new non-uniform dose loss model is proposed and used to explain the experimental results.
Practical Aspects of Forming Ultra-Shallow Junctions by Sub-keV Boron Implants
Authors: Foad M. A. , Murrell A. J. , Collart E. J. H. , de Cock G. , Jennings D. , Current M. I. 
Published: April 2011

ABSTRACTAs the drive towards the production of 100 nm CMOS devices pick up speed, the practical aspect of transistor shallow junction formation, including a large menu of process integration issues, must now be solved in a short order. The most direct path to 50 nm junction depths is through the sub-keV boron implantation and rapid thermal annealing.The material aspects of the process integration centers on: (1) CMOS devices for shallow, highly-activated and abrupt junctions (involving the choice of ion species [B, BF, B10H14, BSi2, etc.], substrate materials [ Cz, Epi, SOI], anneal conditions [ramp rate, soak time, ambient gas], etc.) and (2) Defect-dopant interactions during annealing (including surface reactions of high concentration species [B, F], diffusion and carrier trapping by background and co-implanted species [C, 0, F, etc.].Process data for atomic and electrical activity profiles as well as defect and interface structures will be presented to illustrate progress towards understanding these complex process interactions. A particular focus will be the effects of anneal ambient and rapid temperature rise times approaching the “pike” anneal ideal.
Polytope Models of Metallic Glasses: S-Band Electronic Properties
Authors: Selinger Jonathan V. , Nelson David R. 
Published: April 2011

AbstractInspired by the experiments of Turnbull (1952) on undercooled liquid mercury, many investigators have argued that polytetrahedral short-range order is an important ingredient in the structure of undercooled liquids and metallic glasses. A paradigm for such order is “polytope {3,3,5},” which is a regular lattice of 600 perfect tetrahedra with an icosahedral point symmetry embedded on the surface of a four-dimensional sphere. We present results for the band structure of polytope {3,3,5} in the presence of disclinations, and compare them with band structures obtained from dense random packing models of metallic glasses.
Metal Alkoxide Synthesis of Glasses and Glass-Ceramics
Authors: Drummond Charles H. 
Published: April 2011

AbstractMetal alkoxide syntheses of the general form or can be used to form soluble alkoxides of most metals. Mutual solution of these alkoxides followed by acid or base hydrolysis, drying and calcining results in the formation of fine-grained (<10Å) amorphous powders at low temperatures. Subsequent hot-pressing or calcining leads to densification and/or crystallization. Compositions in the MgO-Al2O3-SiO2 system with ZrO2 contents to 30 mol% are discussed. Also glass formation of transition oxides derived from metal alkoxides of Hf, Zr, Y and Nb in various combinations are presented.
Density and Packing in Uranium Based Metallic Glasses
Authors: Drehman A. J. 
Published: April 2011

AbstractDensity and x-ray diffraction measurements were performed over a wide compositional range of U-Fe and U-Co metallic glass ribbons. The compositional dependence of both the density and the average nearest neighbor distance exhibits a change in slope at approximately 28 at.% transition metal. This suggests an “ideal” glass composition possessing a minimum excess volume. A qualitative model of atomic packing is proposed, which is based on the compositional dependence of the atomic volume and nearest neighbor distance.
Diffusion in Crystalline and Amorphous Solids
Authors: Lazarus David 
Published: April 2011

AbstractDecades of work by a wide variety of techniques were required to establish unambiguously the essential role of simple – and sometimes not so simple – “point” defects in mediating bulk diffusion in crystalline solids. Amorphous solids present new problems for establishing basic diffusion mechanisms. Most experimental techniques which work well for study of diffusion in crystalline solids are useless for study of amorphous materials because of their inherent nonequilibrium structures. A survey of some current results also gives a strong impression that more complex basic mechanisms than simple point defects may be required to account for volume diffusion in these materials.
Application of Nucleation and Growth Theory to the Development of Industrial Products
Authors: May John E. 
Published: April 2011

AbstractIn this paper we discuss some features of the microstructure of large-grainsized very low voltage varistors and the effects of heat treatments on the pre-breakover electrical characteristics. It is shown that a second phase precipitates in the bismuth-rich segregation phase and is thought responsible for the reduced device leakage properties.
MBE Growth and Characterization of Composite InAlAs/In(Ga)As Vertically Aligned Quantum Dots
Authors: Kovsh A. R. , Zhukov A. E. , Egorov A.Yu. , Maleev N. N. , Mikhrin S. S. , Ustinov V. M. , Odnoblyudov V. A. , Musikhin Yu. G. , Livshits D. A. , Tsatsul'nikov A. F. , Maximov M. V. , Shernyakov Yu. M. , Volovik B. V. , Bedarev D. A. , Ledentsov N. N. , Kop'ev P. S. , Alferov Zh. I. , Suvorova A. A. , Werner P. , Bimberg D. 
Published: April 2011

ABSTRACTIn the present work we study the effect of vertical alignment in the quantum dot array formed by successive deposition of several rows of InAlAs and InGaAs quantum dots separated by thin AIGaAs spacer layers. Transmission electron microscopy and photoluminescence studies revealed that the InAlAs QDs characterized by high areal density force InGaAs to be transformed into the denser array as compared to the case of spontaneous transformation. Using denser array of composite quantum dots in the active region of a diode laser leads to the increase in modal gain, decrease in internal loss, and decrease in the threshold current density for short cavity diodes. Room temperature continuous wave output power as high as 3.3 W at 0.87 µm is achieved.
Theory of Addition Spectra in Double Quantum Dots: Single-Particle Tunneling vs Coulomb Interactions
Authors: Rontani M. , Rossi F. , Manghi F. , Molinari E. 
Published: April 2011

ABSTRACTWe study coupled semiconductor quantum dots theoretically using a generalized Hubbard approach, where intra- and inter-dot Coulomb correlation, as well as tunneling effects are described on the basis of realistic electron wavefunctions. We find that the ground-state configuration of vertically coupled double dots undergoes non-trivial quantum transitions as the inter-dot distance d changes; at intermediate values of d we predict a new phase that should be observable in the addition spectra and in the magnetization changes.
New Self-Organized Nanostructure: Chain of Crystalline-Silicon Nanospheres
Authors: Kohno H. , Takeda S. , Iwasaki T. 
Published: April 2011

ABSTRACTWe have grown chains of crystalline-Si nanospheres: the crystalline-Si nanospheres of about 10 nm in diameter are supported in amorphous silica and carbon at a nearly equal spacing by a self-organized process. The self-organized phenomenon was attributed to the periodic instability of catalyst on the top of growing wire and oxidization during the growth of nanowires.
Optical Near-Field Properties of Lithographically Designed Metallic Nanoparticles
Authors: Weeber J.C. , Krenn J.R. , Dereux A. , Bourillot E. , Goudonnet J.P. , Schider B. , Aussenegg F.R. , Girard Ch. 
Published: April 2011

ABSTRACTWe report on the experimental observation of localized surface plasmons sustained by small metallic particles using a photon scanning tunneling microscope (PSTM). The surface plasmons are excited in gold nanostructures tailored by electron beam lithography. The constant height operation of the PSTM allowed a direct comparison with theoretical computations of the distribution of the optical near-field intensity. Plasmon coupling above a chain of Au particles and electromagnetic energy transfer from a resonantly excited nanoparticle to a nanowire are demonstrated. Our experimental results appear to be in good agreement with theoretical computations based on the Green's Dyadic Technique.
Thermal Annealing Effects in Vanadium Pentoxide Films Intercalated with Eu3+
Authors: Oliveira H. P. , Rosolen J. M. , Calefi P. S. , Brunello C. A. , Graeff C. F. O. 
Published: April 2011

AbstractThis work reports on the spectroscopic properties of europium ions intercalated in a vanadium pentoxide matrix, as well as the effects of thermal treatment on its structural and electronic properties. X-ray diffraction, TG/DTA, ESR, luminescence as well as XANES were used in order to characterize the intercalation compound. For the as grown samples, the intercalation of Eu3+ is observed to have little effect in the V2O5 lamellar structure, however the inter-planar spacing grows from 1.19 nm to 1.33nm for a 10% Eu3+ content. The luminescence for the as grown samples are dominated by the host, the same happening with the ESR spectra. However ESR data show that the presence of Eu3+ in the host induces the partial reduction of vanadium to V4+ For samples treated above 873K the luminescence excitation spectra presents a new shoulder at 300 nm, which when excited shows emissions bands typical of the Eu3+ In ESR the same thermal treatments are marked by the appearance of a new broad line assigned to ferromagnetic EuO, as well as the partial oxidation of V4+ to V5+ This result may be correlated to suppression of Eu3+ luminescence due to the presence of water in the neighborhood of Eu3+.
Epitaxial Growth of BaZn1/3Ta2/3O3 Thin-Films for Microwave Applications
Authors: Rong G. , Tsakalakos L. , Browning J. , Newman N. 
Published: April 2011

AbstractBaZn1/3Ta2/3O3 (BZT) ceramics are widely used in current microwave communication applications due to the material's large-dielectric constant (εr > 25), ultra-low loss tangent (tan δ < 2×10−5 at 2 GHz) and a near-zero temperature-coefficient of resonant frequency (τf∼0). In this paper, we report the first growth of epitaxial BZT thin films. The films are grown on MgO substrates using pulsed laser deposition. X-ray diffraction data indicate the films have a disordered pseudocubic perovskite structure with a small tetragonal distortion (i.e. a = b = 4.100 Å; c = 4.088 Å). An optimized substrate temperature of 575°C results in films which are over 98% oriented in the (001) direction and are relatively smooth (rms roughness of 5.2 Å). X-ray diffraction Φ scans of off-axis (202) reflection show four-fold symmetry, indicating a high degree of in-plane epitaxy, albeit with small angle grain boundaries. The refractive index of epitaxial BZT films is inferred to be 5 from Fabry- Perot fringes in optical transmission spectra. Substrate temperatures during growth are limited to ∼600°C as a result of Zn loss.
Influence of Cation Stoichiometry of la1-xSrxCoO3 Bottom Electrodes on the Orientation and Ferroelectric Properties of Pb(Ta0.05ZrO0.48Ti0.47)O3 Films
Authors: Yin J. , Liu Z. G. 
Published: April 2011

AbstractThe Ta-doped PZT films (PTZT) were deposited on Pt/TiO2/SiO2/Si(001) substrates by pulsed laser deposition using La1-xSrxCoO3 buffer layers. The grain orientation of PTZT films is strongly influenced by the cation ratio of La1-xSrxCoO3. The PTZT films deposited using La0.75Sr0.25CoO3 with rhombohedral structure prefer (110)-orientaion, and those deposited using La0.25Sr0.75CoO3 with psuedo-cubic structure prefer (001)-orientation. It is found that the fatigue property of the PTZT capacitors can be improved enormously by using (001)-oriented La0.25Sr0.75CoO3 bottom electrodes. SEM morphology pattern for the surface of PTZT films and for the cross-section show that no obvious interdiffusion occurs across the interfaces. The ferroelectric capacitor La0.25Sr0.75CoO3/PTZT/La0.25Sr0.75CoO3/Pt/TiO2/SiO2/Si(001) shows almost no degradation in its polarization after 1.5×1010 switching cycles at an applied voltage 5 V and a frequency 1MHz.
Nucleation and Growth of Sputter Deposited Zno:Al Thin Films on Soda-Lime Glass Substrates
Authors: Rieth L. W. , Holloway P. H. , Lambers E. 
Published: April 2011

AbstractDegenerately doped thin films of zinc oxide are useful in a variety of applications, including front transparent contacts to Cu(In,Ga)Se2 thin film solar cells and flat panel displays. To gauge the influence of the interface on the performance of sputter deposited ZnO:AI transparent electrodes, the structure and electrical properties of the interfacial region has been investigated during nucleation and growth of the thin films. RF magnetron sputter deposited films with thicknesses ranging from ∼20 to 1580 Å were characterized using Atomic Force Microscopy (AFM), Auger Electron Spectroscopy (AES), Hall measurements, and four point probe. AES spectra of the films with thickness between ∼20 and 60 Å exhibited clear Si (1619eV) peaks suggesting the thin films were discontinuous islands on the substrate. AFM micrographs indicated a distribution of hillocks on the surface which agrees with AES results, and suggest a Volmer-Webber nucleation and growth mechanism. Hall measurements indicated that the films had electron carrier concentrations on the order of 1019 to 1020/cm−3, mobilities of <10cm2V.s, and resistivities on the order of 10−2 to10−3Ω-cm depending on the film thickness. The possible impact of these results on solar cell performance is discussed.
Exotic Doping for Zno Thin Films: Possibility of Monolithic Optical Integrated Circuit
Authors: Fujimura Norifumi , Shimura Tamaki , Wakano Toshifumi , Ashida Atsushi , Ito Taichiro 
Published: April 2011

AbstractWe propose the application of ZnO:X (X = Li, Mg, N, In, Al, Mn, Gd, Yb etc.) films for a monolithic Optical Integrated Circuit (OIC). Since ZnO exhibits excellent piezoelectric effect and has also electro-optic and nonlinear optic effects and the thin films are easily obtained, it has been studied as one of the important thin film wave guide materials especially for an acoustooptic device[1]. In terms of electro-optic and nonlinear optic effects, however, LiNbO3 or LiTaO3 is superior to ZnO. The most important issue of thin film waveguide using such ferroelectrics is optical losses at the film/substrate interface and the film surface, because the process window to control the surface morphology is very narrow due to their high deposition temperature. Since ZnO can be grown at extremely low temperature, the roughness at the surface and the interface is expected to be minimized. This is the absolute requirement especially for waveguide using a blue or ultraviolet laser. Recently, lasing at the wavelength of ultraviolet, ferroelectric and antiferromagnetic behaviors of ZnO doped with various exotic elements (exotic doping) have been reported. This paper discusses the OIC application of ZnO thin films doped with exotic elements.
Pulsed Laser Deposition of Superconductor/Ferromagnetic YBa2Cu3Oy/SrTiO3/La2/3Sr1/3MnO3 Heterostructures
Authors: Trtík V. , Sánchez F. , Ferrater C. , Varela M. , Fábrega L. , Rubi R. , Fontcuberta J. 
Published: April 2011

AbstractYBa2Cu3Oy/SrTiO3/La2/3Sr1/3MnO3 heterostructures have been deposited on LaAlO3(001) and SrTiO3(001) substrates by pulsed laser deposition. First, the influence of deposition conditions on crystallinity and morphology of single LSMO films was examined. Results were used for preparation of heterostructures in tri-layer and cross-strip geometry. Cross-strip geometry was defined by direct shadow mask patterning. Different characterization techniques have been used to determine and correlate the heterostructure properties. A complete analysis of the crystal structure has been carried out with a four-circle difractometer. Morphology has been studied by scanning electron microscopy and atomic force microscopy in order to determine surface roughness and droplet density. Basic electrical properties of films have been determined.
Influence of Post-Deposition Annealing on Lattice Strain, Electrical Transport and Magnetic Properties in Epitaxial La0.8Ca0.2MnO3 CMR Films
Authors: Nath T. K. , Rao R. A. , Lavric D. , Eom C. B. 
Published: April 2011

AbstractThe effect of annealing on 3-dimensional lattice strain, crystallographic domain structure, magnetic and electrical properties of both 250 Å and 4000 Å thick epitaxial La0.8Ca0.2MnO3 (LCMO(x=0.2)) thin films grown on (001) LaAlO3 substrates have been studied. While short annealing time (∼2hrs. at 950 °C in oxygen of 1 atm. pressure) leads to anomalous increase of the peak temperature (Tp) and Curie temperature (Tc) above room temperature and that of the bulk material, longer annealing time (∼10 hrs.) restores the Tp and Tc to almost the same values as that of the as-grown films. Furthermore, as the annealing time is increased, the lattice strain relaxes with film's lattice parameter approaching the bulk value. In-plane and out-of-plane lattice parameters and strain states of the as-grown and annealed films were measured directly using normal and grazing incidence x-ray diffraction. A clear correlation is observed between Tp and perovskite unit cell volume for both the films. Tp is found to increase with the decrease of perovskite unit cell volume. This is attributed to the enhancement of overlap between Mn d orbitals and oxygen p orbitals leading to increased bandwidth and conductivity. Crystalline quality of the films as determined by the full width at half maximum (FWHM) of the x-ray rocking curves, improves with the annealing time. This work highlights the importance of controlling the 3-dimensional lattice strain for optimizing the properties of CMR films.