bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth Temperature and Properties of Ge4Sb3Te3 Films
Authors: Song W. D. , Shi L. P. , Miao X. S. , Hu X. , Lee H. K. , Zhao R. , Chong J. F. , Chong T. C. 
Published: April 2011

ABSTRACTThe growth temperature and properties of Ge4Sb3Te3 thin films are presented in this paper. The critical growth temperature of Ge4Sb3Te3 is between 300 and 340 °C. The Ge4Sb3Te3 films can only be grown on a substrate below the critical growth temperature. The typical resistivity and carrier density are in the order of 10-4 Ωcm and 1021 cm-3 for crystalline phase. It has a rock salt crystal structure with a lattice constant of 0.602 nm. Ge4Sb3Te3 has a better thermal stability but a lower crystallization speed than Ge2Sb2Te5.
Preparation of Strontium Bismuth Tantalate Thin Film by Liquid-Delivery Metalorganic Chemical Vapor Deposition
Authors: Silinskas M. , Lisker M. , Kalkofen B. , Matichyn S. , Garke B. , Burte E. 
Published: April 2011

ABSTRACTThin films of BiOX, SrXTaYO, and SrXBiYTaZO (SBT) were deposited by liquid-delivery metalorganic chemical vapor deposition (MOCVD). The substrate temperature and the deposition pressure were varied from 300 to 600°C and from 0.35 to 7 mbar, respectively. Triallylbismuth (Bi-1), triphenylbismuth (Bi-2) or alkyl bismuth (Bi-3) and strontium bis-pentaethoxy-methoxyethoxy tantalate (Sr-Ta) were used as Bi precursors and as Sr-Ta precursor, respectively. X-ray photoelectron spectroscopy (XPS), ellipsometry, and scanning electron microscopy (SEM) were carried out to characterize the film properties.The growth rates of the MOCVD of BiOX and SrXTaYO were compared to the growth rate of SBT to obtain information about mutual interaction between the precursors. The growth rate of bismuth oxide thin films deposited from Bi-1 and Bi-2 was low (∼10 nm/h at 0.35 mbar). The growth rate of strontium tantalate films was higher (up to 50 nm/h) and depended strongly on the temperature. Eight times higher (∼400 nm/h) growth rates of BiOX and SBT films were observed for the Bi-3 precursor. The deposition rate of the SBT films was quite similar to the rate of the bismuth oxide. However, the deposition rate of SBT was always lower than the deposition rate of the single Bi precursors. The growth rate significantly depended on the deposition pressure. A decrease of the deposition pressure in the reactor chamber reduced the deposition rate of BiOX, SrXTaYO, and SBT, but on the other hand, it improved the uniformity of the film thickness over the entire 150 mm wafer surface.The XPS measurements showed a deficit of bismuth in the SBT films even though the concentration of the Bi-1 or Bi-2 precursor was several times higher compared to the Sr-Ta precursor. This problem disappeared when Bi-3 source was used.
Prospect of Emerging Nonvolatile Memories
Authors: Jeong Hongsik , Kim Kinam 
Published: April 2011

ABSTRACTConventional nonvolatile memories such as Flash and EEPROM memory have successfully evolved toward high density and low cost. Especially, the market and density of flash memories has grown rapidly which leads semiconductor technology. However, there have been concerns about whether this successful progress can be maintained in the future nano era and can satisfy the requirement of diversified future IT market. Flash memories have the advantage of high density with small cell size and by contraries the disadvantage of slow writing speed and limited endurance. This slow writing speed and limited endurance is not aligned with the trend of high speed and reliability for future semiconductor memories.The future for these conventional nonvolatile memories forces many research groups and companies to develop alternative memories with ideal memory characteristics such as non-volatility, high density, high speed, and low power, which none of the conventional memories can satisfy at the same time.In this article, I will evaluate the characteristics of future nonvolatile memories such as ferroelectric random access memory (FRAM), magnetoresistive random access memory (MRAM) and phase change random access memory (PRAM). These memories have been recently evaluated because of the possibility that they can overcome the challenges that conventional memories are facing. Finally we will review critical technology barriers in developing future memory and predict the promising technology to overcome the barriers in conventional and emerging new memories, which will be technology guidelines for future memory development.
Effect of Deposition Temperature and Post-Heat-Treatment Condition on the Characteristics of (100)-Self-Orientation LaNiO3 Films Prepared by RF Magnetron Sputter Deposition
Authors: Takahashi Kenji , Suzuki Muneyasu , Oikawa Takahiro , Chen Haydn , Funakubo Hiroshi 
Published: April 2011

ABSTRACTLa-Ni-O films were deposited at deposition temperature ranging from 250 to 540°C by rf magnetron sputter deposition. The effects of deposition temperature and the following heat-treatment condition on the constituent phases and characteristics of LaNiO3 films were investigated. LaNiO3 phase was obtained at the deposition temperature of 250 and 360°C, while La-rich phase of La2NiO4 was appeared above 540°C. Crystalline phases of resultant films after the following heat-treatment strongly depended on the partial pressure of oxygen gas in ambience, i.e., in case of the heat-treatment at 800°C, diffraction peaks originated from LaNiO3 phase disappeared on XRD patterns in pure nitrogen gas ambience, while impurity peaks of NiO appeared in oxygen-excess (>50%) ambience. As a result, LaNiO3 films with high crystallinity and the same lattice parameter as the bulk one were obtained in the deposition at 360°C followed by the heat-treatment at 700°C in air.
Pulsed DC Sputtered Aluminum Nitride: A Novel Approach To Control Stress And C-axis Orientation
Authors: Soussan Philippe , O'Donnell Kathy , D'Haen Jan , Vanhoyland Geert , Beyne Eric , Tilmans Harrie A. C. 
Published: April 2011

ABSTRACTThis paper reports on a novel low temperature sputter deposition of AlN on an Al substrate, yielding films with stresses and crystalline orientation comparable to those of films deposited on Pt. The study focuses on the importance of the initial film growth step on both the stress and crystalline orientation of the film. The AlN layer is deposited using Pulsed DC (250 kHz, 90% duty cycle) magnetron reactive sputtering (93% N2, 7% Ar) using an Al target. The substrates are 150mm Si wafers with an aluminum seed layer (100 nm). The thickness of the AlN films is ≈2.5μm with uniformity across the wafer of 0.4%. The films were deposited in 4 passes of 0.625μm each to avoid overheating of the substrate. The influence of the substrate bias (0 V, 80 V and 120V) and argon pre-sputtering of the aluminum substrate been investigated. The film stress, and to a smaller extent the crystalline orientation, were mainly driven by the properties of the film deposited during the first pass. The bias is useful at the beginning of the film growth for stress control. This study suggests that it is beneficial not to use bias during the entire film deposition. With this approach, it was possible to deposit c-axis oriented AlN layers on Al with a FWHM of the rocking curve of 1.63° and low stress (<300MPa).
Integrated On-chip Planar Solenoid Inductors with Patterned Permalloy Cores for High Frequency Applications
Authors: Kim Jinsook , Ni Weiping , Kan Edwin C. 
Published: April 2011

ABSTRACTThe on-chip magnetic inductors with patterned permalloy (Ni80Fe20) cores are fabricated on Si-substrates with different resistivities and thicknesses as well as on thin membranes. With the patterned permalloy cores, the on-chip magnetic inductors achieve high self-resonant frequencies over 25GHz in thin membranes. To distinguish the influence from the permalloy core patterns and substrate losses on the inductance and quality factor, multiple solenoids in series and parallel are designed to investigate the resistive, capacitive, and magnetic coupling losses.
Prevention of InP/InGaAs/InP Double Heterojunction Bipolar Transistors from Current Gain Reduction during Passivation
Authors: Min Byoung-Gue , Lee Jong-Min , Kim Seong-Il , Ju Chul-Won , Lee Kyung-Ho 
Published: April 2011

ABSTRACTA significant degradation of current gain of InP/InGaAs/InP double heterojunction bipolar transistors was observed after passivation. The amount of degradation depended on the degree of surface exposure of the p-type InGaAs base layer according to the epi-structure and device structure. The deposition conditions such as deposition temperature, kinds of materials (silicon oxide, silicon nitride and aluminum oxide) and film thickness were not major variables to affect the device performance. The gain reduction was prevented by the BOE treatment before the passivation. A possible explanation of this behavior is that unstable non-stoichiometric surface states produced by excess In, Ga, or As after mesa etching are eliminated by BOE treatment and reduce the surface recombination sites.
Stroboscopic X-Ray Diffraction Measurements of sub-ns Domain Dynamics in Ferroelectric Films
Authors: Zolotoyabko E. , Quintana J. P. , Towner D. J. , Wessels B. W. 
Published: April 2011

ABSTRACTWe used the Advanced Photon Source (APS) at Argonne National Laboratory to perform fast (ps range) time-resolved diffraction measurements of the dynamic characteristics in BaTiO3 films subjected to strong high-frequency electric fields. The time-dependent lattice response measured at frequencies between 6.5 MHz and 1.3 GHz revealed damped domain movements with attenuation time rapidly increasing with electric field frequency, v. We found that at frequencies higher than ν ∼ 600 MHz the domain motions in BaTiO3 films become heavily damped, information that may be important to future device operation. A minimum attenuation time, τ ∼ 330 ps, measured at ν = 1.3 GHz was limited by the time constant of the electrical circuit.
Temperature Dependent Dielectric Properties of Polycrystalline 96%Al2O3
Authors: Chen Liang-Yu , Hunter Gary W. 
Published: April 2011

AbstractPolycrystalline Al2O3 substrates have been proposed and tested for high temperature micro devices packaging intended for operation at temperatures up to 500°C. The dielectric properties of this material, including dielectric constant and effective volume conductivity, at elevated temperatures are of interest, especially for RF packaging applications. This article reports temperature dependent dielectric properties of polycrystalline 96% Al2O3 substrates from room temperature to 550°C measured by the AC impedance method at 120 Hz, 1 kHz, 10 kHz, 100 kHz, and 1 MHz. We observed negative temperature coefficients of volume electrical conductivity of 96% Al2O3 at 1 k, 10 k, and 100 kHz between room temperature and 50°C. The dielectric constant of the material increases significantly with temperature at frequencies below 10 kHz. The physical mechanisms of these dielectric behaviors of 96% Al2O3 at elevated temperatures are discussed.
Solvable Model of Two-Dimensional Magnetophotonic Crystal
Authors: Khanikaev A. B. , Inoue M. , Granovsky A. B. , Vinogradov A.P. 
Published: April 2011

ABSTRACTWe present theoretical investigation of two-dimensional (2D) magnetophotonic crystal (MPC) with square lattice constructed from two infinite arrays of magnetoactive dielectric sheets at right angle, in the limit of very small sheet thickness and very high dielectric constant, such that their product is constant. Alteration of band structure by external magnetic field is studied. We show that optical activity reduces symmetry of the system and removes degeneracy in the photonic band structure. Also, despite of natural weakness of the magnetooptic activity, dispersion near band edges is found to be strongly sensitive to external magnetic influence.
Optical and Transport Effects in LaGa1-xMnxO3: Experiment and Modeling
Authors: Noginova N. , Chen F. , Chelule G. , Gavrilenko V. I. 
Published: April 2011

AbstractCharge transport and optical properties have been studied experimentally and theoretically in a series of LaGa1-xMnxO3 crystals in the dependence on the material composition. Electron energy structure and optical functions of LaGa1-xMnxO3 are calculated by ab initio pseudopotential method within density functional theory using generalized gradient approximation. Theoretical results are discussed in comparison with the experimental data for different alloy compositions.
Room Temperature Ferromagnetic Properties of Epitaxially Grown Zn1-xCoxO Thin Films
Authors: Yun F. , Rengarajan Varatharajan , Nause J. , Morkoç H. 
Published: April 2011

ABSTRACTWe have conducted a systematic magnetic characterization of a series of Zn1-xCoxO samples with different cobalt composition. The Zn1-xCoxO thin films were epitaxially grown by metal organic chemical vapor deposition (MOCVD) on quartz and ZnO substrates. The Co composition was adjusted by controlling the bubbler temperature and carrier gas flow. The magnetization measurements were performed using a Quantum Design MPMS system, which utilizes a superconducting quantum interference device (SQUID) magnetometer. Magnetic hysteresis curves were observed at 5K which persisted up to 300K, possibly characteristic of ferromagnetic behavior. Temperature dependent magnetization was recorded under both zero-field cooled (ZFC) and field cooled (FC) conditions. Changes of magnetization were observed under ZFC and FC conditions in some samples from 5K up to 300K. Composition-dependent changes in magnetization were also observed among samples with different cobalt doping, indicative of ferromagnetism related directly to cobalt incorporation. Magnetic field dependent magnetization at various temperatures with field up to 5 Tesla suggests the Zn1-xCoxO layers were not paramagnetic.
Structure, proton incorporation and transport properties of ceramic proton conductor Ba(Ce0.7Zr0.2Yb0.1)O3-δ
Authors: Li Yaping , Kolesnikov Alexander I. , Richardson James W. , Zuo Chendong , Lee Tae H. , Balachandran U. 
Published: April 2011

ABSTRACTDense ceramics with composition Ba(Ce0.7Zr0.2Yb0.1)O3-β (BCZY) were synthesized by solid state reactions, and their structures were characterized by Rietveld refinements of time-of-flight (TOF) neutron diffraction data collected for the samples at high-temperature and controlled atmospheres. The structure phase transition from orthorhombic Imma to cubic Pm3m was observed at the temperature between 500 and 700°C and in flowing 100ppm H2/Ar gases. At 900°C, the sample was subsequently exposed to different oxygen partial pressures (pO2, ranging from ∼10−17 to ∼10−23 atm) and water vapor pressures (pH2O) up to ∼0.18 atm. The expansion of lattice parameters of BCZY, instead of following the normally expected relationship with pO2, was actually correlated with the increase of pH2O, implying proton incorporation into the structures. The presence of H-containing species in the structure was confirmed by comparing both inelastic neutron scattering spectra and neutron diffraction data collected for dry and “wet” samples at 10K. The observed vibrational peaks at 104 and 150 meV and absence of a peak around 420 meV indicate the hydrogen occupation in the structure but the absence of any hydroxyl groups (hydrogen covalently bonded to oxygen). Electrical conductivities of BCZY were investigated at different temperatures in both dry and wet conditions.
Preparation and Hydrogen Pumping Characteristics of BaCe0.8Y0.2O3-δ Thin Film
Authors: Lee T. H. , Harder B. J. , Zuo C. , Dorris S. E. , Balachandran U. 
Published: April 2011

ABSTRACTThin films of BaCe0.8Y0.2O3-δ (BCY) were prepared by colloidal spray deposition. Dense, crack-free BCY films having a grain size of 2–7 μm were successfully deposited on NiO/BCY substrates. Electrochemical hydrogen pumping with the BCY films showed that the maximum current density increased with temperature. The maximum current density was sensitive to the moisture in the cathode gas; the value obtained with a dry cathode gas was only half that with a wet cathode gas. A very high hydrogen-pumping current density of 3.4 A/cm2 was measured at 700°C with an applied voltage of 1.5 V.
Oxygen Permeable Properties of Ce0.8Gd0.2O1.9 - MFe2O4 Composite Thin Films Prepared by a Chemical Solution Deposition Method
Authors: Kagomiya Isao , Iijima Takashi , Takamura Hitoshi 
Published: April 2011

ABSTRACTCe0.8Gd0.2O1.9 (CGO) - MFe2O4 (M=divalent cation) is a composite-type oxygen-ionic and electronic mixed conductor. Dense nanocrysalline CGO-CoFe2O4 thin films with a thickness of approximately 1 μm were prepared on CGO porous substrates by a chemical solution spin-coating method. The oxygen permeable flux of the thin film was investigated in temperature range of 700°C - 800°C without physical leak of N2 gas. The permeable flux depends on the measuring time, when the measuring temperature was kept at 750°C before increasing to 800°C. This fact suggests that the O2 permeable properties were affected by a slight change of the film morphology and the crystallinity.
Electrical and Hydrogen Transport Properties of SrCe0.8Yb0.2O3−δ/Ni Cermet Membranes
Authors: Song S.-J. , Lee T. H. , Chen L. , Zuo C. , Dorris S. E. , Balachandran U. 
Published: April 2011

AbstractResearch on hydrogen separation membranes is motivated by the increasing demand for an environmentally benign, inexpensive technology for separating hydrogen from gas mixtures. Although most studies of hydrogen separation membranes have focused on proton-conducting oxides by themselves, the addition of metal to these oxides increases their hydrogen permeability and improves their mechanical stability. This study began by determining the electrical and hydrogen permeation properties of SrCe0.8Yb0.2O3−δ (SCYb). The results showed that the hydrogen permeation rate is limited by electron flow at the investigated temperatures (600 – 900°C). To further enhance hydrogen permeability, a cermet (i.e., ceramic-metal composite) membrane was made by adding Ni to the SCYb. The cermet showed no phase change after sintering in a reducing atmosphere. At 900°C, with 20% H2 /balance He as a feed gas (pH2O = 0.03 atm), the hydrogen permeation rate was 0.113 cm3/min-cm2 for Ni/SCYb (0.43-mm thick) and 0.008 cm3/min-cm2 for SCYb (0.7-mm thick). The dependences of hydrogen permeability on temperature, thickness, and hydrogen partial pressure gradients are also determined. The results demonstrate that adding Ni to SCYb considerably increases its hydrogen permeability by increasing its electron conductivity.
Specificity of the Local Structure of Nanocrystalline Doped Ceria Solid Electrolytes
Authors: Sadykov Vladislav A. , Frolova Yulia V. , Kriventsov Vladimir V. , Kochubei Dmitrii I. , Moroz Ella M. , Zyuzin Dmitrii A. , Potapova Yulia V. , Muzykantov Vitalii S. , Zaikovskii Vladimir I. , Burgina Elena B. , Borchert Holger , Trukhan Sergei , Ivanov Vyacheslav P. , Neophytides Stylianos , Kemnitz Erhard , Scheurell Kerstin 
Published: April 2011

ABSTRACTThis work presents results of studies of the structural features of nanocrystalline doped Ce1−xMexO2−y samples (Me = Sm, Bi, Gd; X = 0–0.5) prepared via the polymerised precursor (Pechini) route by using a combination of diffraction (XRD, TEM, WAXS on SR) and spectroscopic (EXAFS, Raman, FTIRS of lattice modes, XPS, SIMS) methods.
Influence of B-site ion valence on ion conduction for perovskite-type Li ion conductor, (La2/3–1/3p Lip)(Mg1/2W1/2)O3 (p =0.05, 0.11 and 0.14)
Authors: Katsumata Tetsuhiro , Takahata Megumi , Mochizuki Nobuko , Inaguma Yoshiyuki 
Published: April 2011

AbstractWe synthesized perovskite-type Li ion conductor, (La2/3–1/3p Lip)(Mg1/2W1/2)O3 (p =0.05, 0.11 and 0.14), and investigated the variation of the Li ion conductivity with p. Furthermore, the variation of the activation energy with the valence of B-site ion was elucidated from the site potential at A-site and a bottleneck position. As results, it is suggested that the Coulomb repulsion between B-site and Li ions at the bottleneck dominates the activation energy for (La2/3–1/3p Lip)(Mg1/2W1/2)O3.
Growth of Ceria-Zirconia Electrolyte Nanostructures with High Interface Density by Using Sol-gel/GLAD Combination
Authors: Saraf Laxmikant , Matson D. W. , Young J. S. , Wang C. M. , Thevuthasan S. 
Published: April 2011

ABSTRACTWe report a process for the successful incorporation of ceria in to yttria-stabilized zirconia (YSZ) columnar nanostructures grown by glancing angle deposition (GLAD) technique, resulting in high interface density columnar nanostructures. The incorporation of ceria into YSZ columns is confirmed by scanning electron microscopy (SEM) in a cross sectional geometry with in-situ analysis of elemental x-ray mapping technique and energy dispersive x-ray analysis (EDX). Controlled engineering of such nanostructures is potentially important in the future development of high efficiency solid oxide fuel cell electrolytes. The challenges and advantages of this process are discussed.
Advance in Nanostructural Electrochemical Reactors for NOX Treatment in the Presence of Oxygen.
Authors: Hamamoto Koichi , Fujishiro Yoshinobu , Awano Masanobu , Katayama Shingo , Bredikhin Sergei 
Published: April 2011

ABSTRACTDramatic improvement in the selective separation and purification of NOX in exhaust gases by an electrochemical reactor with a catalytic electrode has been achieved. The novel electrochemical cells for NOX decomposition were developed by nano-scale control of penetrating pores from the catalytic electrode surface to the bottom of the catalytic electrode layer. The penetration pores and nano-size Ni grains are self-assembled at NiO/YSZ interfaces in the catalytic electrode by oxidization-reduction reaction of the NiO during the cell operation. In order to use reduced Ni for NOX decomposition reaction efficiently, we successfully designed a functional multilayer catalytic electrode. By multilayering of the catalytic electrode, adsorption and decomposition of coexisting oxygen in exhaust gases was suppressed and the selectivity of NOX decomposition reaction is improved. Structural change of the catalytic electrode as a result of the electrochemical processes was investigated and correlated with the NO decomposition properties of the cell.
Dendritic CuIn Films Grown by Electroless Deposition
Authors: Lane David W , Painter Jonathan D , Rogers Keith D , Forbes Ian , Miles Robert W , Hynes Kathleen M 
Published: April 2011

ABSTRACTCuInS2 films are often grown in a two-step process with the deposition of a Cu-In alloy followed by high temperature sulphurisation in either S vapour or H2 S. Numerous techniques exist for the deposition of Cu-In. In this work Cu-In films have been deposited on tin oxide coated glass using the electroless deposition technique, a low cost, low temperature approach. The films were found to consist of a two layered structure. Initially, Cu islands grew forming a layer on the substrate. The deposition process subsequently produced dendritic Cu-In alloys from the tops of the Cu islands. Various CuIn phases were observed, namely Cu9In4 and CuIn, the presence of which was related to the solution pH. None of the films were found to contain metallic In, indicating that this process may be well suited to subsequent high temperature sulphurisation.