bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Ca(OH)2-Treated Ceramic Microspheres on the Mechanical Properties of High-Temperature Lightweight Cement Compos
Authors: Sugama Toshifumi 
Published: June 2019

ABSTRACTThe compressive strength and water permeability of high-temperature lightweight cementing materials containing sillimanite-based hollow microspheres as a filler can be improved by treating the surfaces of the microspheres with a Ca(OH)2-saturated solution at temperatures up to 200°C. The precipitation of an epitaxial layer formed by an interaction between a hot calcium hydroxide solution and the surface of the sphere plays an essential role in developing favorable bonding characteristics at the interfaces and in promoting the hydration of the cement matrix. The properties of the composites include a slurry density of <1.2 g/cc at 25°C, a 300°C-24 hour compressive strength of >1015 psi (7.0 MPa), a water permeability of <10-4 Darcy, and a bulk density of <1.0 g/cc. It was observed that tobermoritetruscottite transformation and anorthite formation during autoclave exposure for 180 days in brine at 300°C results in slight strength reductions and increased water permeability.
The Microstructure of Cement Aggregate Interfaces
Authors: Zhang X. , Groves G. W. , Rodger S. A. 
Published: June 2019

ABSTRACTMortar bars of tricalcium silicate or ordinary portland cement with small aggregate particles have been sectioned and examined in the transmission electron microscope (TEM). The presence of calcium silicate hydrate (CSH) gel at the interface is seen by TEM in many cases in intimate contact with the aggregate. In some cases calcium hydroxide (CH) is observed near the interface but is seldom in contact with the aggregate. Microanalysis in the TEM shows that in the case of reactive silica aggregate a gel of relatively low Ca:Si ratio is found at the interface. Aggregates of different degrees of reactivity and mortars of different ages are compared. It is suggested that interface fractures may occur beyond the coating of CSH rather than at the true interface in the case of the type of particles we have studied.
Improvement of Compressive Strength in Ordered Polymer Films and Fibers by Sol-Gel Glass Processing
Authors: Kovar Robert F. , Haghighat R. Ross , Lusignea Richard W. 
Published: June 2019

ABSTRACTSol-gel glass processing of poly (benzobisthiazole) (PBZT) films increased the compressive strength of PBZT/PEEK film laminates by more than four times, with the potential for further improvement indicated. This was accomplished by infiltrating sol-gel glass precursor reagents into microfibrillar regions of PBZT film, forming PBZT/sol--gel glass microcomposites that combined the high compressive strength of glass with the exceptional strength and toughness of PBZT ordered polymer. The presence of glass within PBZl/sol-gel microcomposite films inhibited the buckling of microfibrils during film compression, greatly increasing the resistance of the films to compressive failure. The use of sol-gel glass compositions that fuse at temperatures within thermal stability limits of PBZT (600 C) should further improve PBZI film compressive strength.Preliminary experiments involving sol-gel processing of PBZT fibers did not show improvements in fiber compressive strength. Microscopic analysis of treated fibers indicated that fiber abrasion and kinking had occurred during batch processing steps.The results of our continuing efforts to achieve 100 Ksi compressive strength in PBZT films and fibers will be discussed.
Viscosity, Structural Relaxation and Defect Annihilation Kinetics of Amorphous Si
Authors: Witvrouw Ann , Spaepen Frans 
Published: June 2019

AbstractSubstrate curvature measurements were used to monitor viscous flow in ion beam sputtered amorphous Si for temperatures ranging from 150 to 400 °C. The viscosity increases linearly with time, characteristic of a bimolecular defect annihilation process. This is consistent with the defects governing viscous flow being dangling bonds. The isoconfigurational activation enthalpy for the viscosity is 1.8 ±.3 eV.
Electron Cyclotron Resonance Hydrogen Plasma Induced Defects in Thermally Grown and Spuiter Deposited SiO2
Authors: Hallett W. L. , Ditizio R. A. , Fonash S. J. 
Published: June 2019

ABSTRACTIn this study we show that upon exposure to electron cyclotron resonance hydrogen plasmas, both thermally grown and sputter deposited oxides are degraded, resulting in large shifts of flat band voltage, and increases in fixed charge and interface state density.
Study of the Orientation of Y1Ba2cu/3O7−x Thin Films In-Situ Prepared by Reactive Coevaporation With RF Activated Oxygen-Ozone Plasma.
Authors: Nagata M. , Nojima H. , Shintaku H. , Koba M. 
Published: June 2019

ABSTRACTSuperconducting films of Y1Ba2Cu3O7−x have been prepared in-situ onto SrTiO3 (100) substrates by reactive coevaporation with rf activated oxygenozone plasma. Crystal quality and orientation of the films were evaluated as a function of substrate temperature(Ts). The films evaporated at Ta between 680°C, and 690°C had an a,b-axis orientation perpendicular to the substrate. The zero resistance temperature(Tc) of the film evaporated at Ts, of 690°C was 80K. The films evaporated at Ta above 700°C had c-axis orientation. The Ts of the film evaporated at a Ts, of 710°C was 90K.
Preparation of Optically Smooth Surfaces of High TcSuperconducting Films
Authors: kim J. H. , Kapitulnik A. , Harris J. S. , Char K. , Bozovic I. , Lee W. Y. 
Published: June 2019

ABSTRACTWe report optical studies of predominantly c-axis oriented high-Tc superconducting films before and after ion milling. A significant increase in midinfrared reflectivity resulted from ion milling of a few thousand Å Features associated with α-axis texture vanished after ion milling, resulting in pure c-axis films. This suggests that α-axis grains reside mostly near the surface in post-annealed high-Tc superconducting films. Therefore, even after annealing (for the purpose of raising Tc), highly oriented c-axis films can be retained by ion milling. This may be important for device applications where optically smooth surfaces and interfaces are to be routinely prepared.
Persistent Photoconductivity And Thermal Recovery Kinetics Of Low Energy Ar + Bombarded GaAs
Authors: Vaseashta A. , Burton L. C. 
Published: June 2019

ABSTRACTKinetics of persistent photoconductivity, photoquenching, and thermal and optical recovery observed in low energy Ar+ bombarded on (100) GaAs surfaces have been investigated. Rate and transport equations for these processes were derived and simulated employing transport parameters, trap locations and densities determined by deep level transient spectroscopy. Excellent correlation was obtained between the results of preliminary simulation and the experimentally observed values. The exponential decay of persistent photoconductivity response curve was determined to be due to metastable electron traps with longer lifetime and is consistent with an earlier proposed model.
Evidence of Oscillating Oxide Growth Mechanism during Oxygen Plasma Oxidation of Silicon
Authors: Nguyen Son , Nguyen Tue , Dobuzinsky D. , Gleason R. , Gibson M. 
Published: June 2019

ABSTRACTEvidence of an oscillating thin-film oxide growth reaction was observed on silicon surfaces during low RF power (13.6 MHz, < I W/cm2) plasma oxidation. Ex-situ ellipsometric, X-ray photoelectron (XPS) and Fourier-transform infrared (FTIR) spectroscopic measurements show that the oscillating growth layer is silicon-rich oxide and its oscillating thickness is very sensitive to both surface preparation and plasma oxidation conditions. A simple low-energy oxygen ion-assisted plasma oxidation and sputtering mechanism is proposed to clarify and to account for the observed oscillating oxide growth reaction.
Room Temperature Nitridation and Oxidation of Si, Ge and Mbegrown Sige Using Low Energy Ion Beams (0.1-1 Kev).
Authors: Vancauwenberghe O. , Hellman O. C. , Herbots N. , Olson J. L. , Tan W. J. , Croft W. J. 
Published: June 2019

ABSTRACTDirect Ion Beam Nitridation (IBN) and Oxidation (IBO) of Si, Ge, and Si0.8Ge0.2 were investigated at room temperature as a function of ion energy. The ion energies were selected between 100 eV and 1 keV to establish the role of energy on phase formation and film properties. Si0.8Ge0.2 films were grown by MBE on Si (100) and transferred in UHV to the ion beam processing chamber. The modification of composition and chemical binding was measured as a function of ion beam exposure by in situ XPS analysis. The samples were nitridized or oxidized using until the N or O 1s signal reached saturation for ion doses between 5×1016 to 1×1017 ions/cm2. Combined characterization by XPS, SEM, ellipsometry and cross-section TEM showed that insulating films of stoichiometric SiO2 and Si-rich Si3N4 were formed during IBO and IBN of Si at all energies used. The formation of Ge dielectric thin films by IBO and IBN was found to be strongly energy dependent and insulating layers could be grown only at the lower energies (E ≤ 200 eV). In contrast to pure Ge, insulating SiGe-oxide and SiGe-nitride were successfully formed on Si0.8Ge0.20.2 at all energies studied.
Atomic Hydrogen Passivation of High Energy Hydrogen Implants
Authors: Srikanth K. , Shenal J. , Ashok S. 
Published: June 2019

ABSTRACTHigh-energy hydrogen ion (proton) implantation is used in Si for creating defects, while low-energy H is known for passivation of a variety of defects and impurities. We have carried out a study of low-energy (<0.4 keV) H passivation of defects produced by 100 keV H implantation. Both Schottky barrier transport and deep level transient spectroscopy measurements give evidence for self-passivation of defects produced by H.
Synthesis of Boron Nitride Film by Ion Beam Deposition
Authors: Xia Z. , Zhang G. L. , Lin W. L. 
Published: June 2019

ABSTRACTThin films of cubic boron nitride (c-BN) together with hexagonal one (h-BN) have been prepared by using the ion beam deposition method (IBD). Boron was deposited onto silicon wafers by a sputtering beam of 600 eV argon ions, and the growing films were simultaneously irradiated by nitrogen ions at 200 eV. The films were subsequently characterized by infrared absorption (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and microhardness measurements. The IR spectra show the evidence of BN layer formation by the absorption peaks at about 1350, 1120 and 810 cm−1, which are in good agreement with those of bulk BN.
The Role of Dilution Gas in Plasma Deposition of Amorphous Hydrogenated Carbon
Authors: Lu Hsueh Yi , Petrich Mark A. 
Published: June 2019

ABSTRACTWe have studied the effect of hydrogen dilution on the structural and optical properties of plasma-deposited amorphous hydrogenated carbon. Electron spin resonance reveals that the dangling bond density does not change with hydrogen dilution, presumably because there is an excess of hydrogen present during these depositions. Information from 13C NMR, however, shows that hydrogen dilution induces changes in composition, hydrogenation, sp2/sp3 carbon bonding ratio, and the size of sp2 bonded clusters. These changes modify the electronic band structure, as observed by shifts in optical measurements.
Ion Bean Deposition of Multilayer Magnetic Films
Authors: Senda Masakatsu 
Published: June 2019

ABSTRACTThis work investigates the modification of Fe based ion beam sputtered magnetic multilayer films in order to realize good soft-magnetic properties. Fe is used as the main magnetic material because it is the single element with the highest saturation magnetization. Then, I attempt to obtain Fe with zero magnetostriction and soft-magnetic properties artificially using a multilayering technique, while maintaining the highest possible saturation magnetization. Magnetostriction is changed by one of two following causes: by a change in the balance between positive and negative magnetostriction layers, as seen in for example Fe/Co film, or by a change in crystal orientation, as seen in for example Fe/Si02 film. Multilayer film with positive and negative magnetostriction layers is confirmed to show the same inverse magnetostrictive effect as that in uniform film. Also, the small crystal grains and the magnetostatic coupling cause a decrease in anisotropy dispersion, and lead to soft-magnetic properties, in the multilayer films. Additionally, the minimum coercivity in Fe/ SiO2 film corresponds well to the maximum in-plane uniaxial anisotropy and the minimum perpendicular anisotropy where magnetization is restricted almost completely in the plane.
Island Evolution During Early Stages of Ion-Assisted Film Growth: Ge ON SiO2
Authors: Nikzad Shouleh , Atwater Harry A. , Watson Thomas J. 
Published: June 2019

ABSTRACTMicrostructure evolution has been studied in the early stages of growth of polycrystalline Ge on SiO2 in ultrahigh vacuum by ion beam-assisted deposition, and has been systematically compared to conventional thermal film growth. Experimental results indicate that, at equivalent substrate coverages, films grown by ion beam-assisted deposition exhibit increased island density and decreased island size with respect to thermally-deposited films. The increased island density is not a result of an increased island nucleation rate associated with defects produced in the SiO2 substrate during ion beam-assisted deposition. Instead, a new model for ion beam-induced adatom desorption from islands is proposed to account for the increased island density and decreased island size.
Properties of SiO2 Films Fabricated by Microwave Ecr Plasma Processing with and Without Energetic Particle Bombardment During Film Deposition Part I. Fabrication Processes and Physical Properties
Authors: Chau T. T. , Mejia S. R. , Kao K. C. 
Published: June 2019

ABSTRACTSilicon dioxide (SiO2) films were fabricated by microwave ECR plasma processing. Two groups of films were fabricated; group A with the substrates placed in a position directly facing the plasma so that the substrates as well as the on-growing films were subjected to bombardment of energetic particles produced in the plasma, and group B with the substrates placed in a processing chamber physically separated from the plasma chamber in order to prevent or suppress the damaging effects resulting from these energetic particle bombardment. The systems used for fabricating these two different groups of samples are described. The films were deposited at various deposition temperatures. On the basis of the deposition rate as a function of deposition temperature the film growth for group A samples is due mainly to mass-limited reaction, and that for group B samples is due to surface rate limited reaction. The stoichiometric level for group A does not change with deposition temperature though the films density increases with increasing deposition temperature. However, group B samples exhibit an off-stoichiometric property but they become highly stoichiometric as the deposition temperature is increased beyond 200 °C
Cubic Boron Nitride Prepared by an ECR Plasma
Authors: Osaka Y. , Okamoto M. , Utsumi Y. 
Published: June 2019

ABSTRACTA number of deposition techniques for cubic BN films from the vapor phase at low pressures have been proposed. We show that the essential factor for creating cubic BN films is a negative self-bias applied to the substrate. The optical and mechanical properties of the deposited films are characterized by reflectance and stress measurements, respectively.
The ECR-Plasma Deposition of Silicon Nitride on a Tunnel Oxide
Authors: Barbour J. C. , Stein H. J , Outten C. A. 
Published: June 2019

ABSTRACTGate dielectric-quality silicon nitride films were deposited on a tunnel oxide from an SiH4/N2 gas mixture using an electron cyclotron resonance (ECR) plasma. Electrical characteristics depend not only upon the quality of the nitride film but also upon the state of the interfacial oxide. Quasi-static and 1 MHz capacitance-voltage measurements show that a nitride film deposited at 200°C on 2 nm thick thermally-grown oxide (tunnel oxide) on an unbiased Si substrate have an interface state density of l.5×1011/cm2-eV. Time-of-flight elastic recoil detection (TOF-ERD) was used to examine the level of mixing between the tunnel oxide and the deposited silicon nitride as a function of bias voltage. TOF-ERD showed that for an applied bias of −350 V (ion energy ≈ 380 eV), the deposition of a 10 nm thick film was completely mixed to form an oxynitride whereas the tunnel oxide remained intact for an unbiased sample. (Interdiffusion resulting from energetic-beam heating was ruled-out as a possibility for the mixing.)
Laser and Thermal Annealing of Co-Implanted Si Studied by Mossbauer Spectroscopy
Authors: Langouche G. , de Potter M. , Van Rossum M. , de Bruyn J. , Dezsi I. , Coussement R. 
Published: June 2019

ABSTRACTMössbauer spectroscopy was used to study the lattice location of Fe in Si. Strikingly different spectra were recorded depending on the implantation dose and implantation temperature. Drastic changes were also observed in the spectra upon thermal treatment or laser irradiation of the samples. Implantation profiles of several of these sources were also measured. Laser irradiation and thermal annealing above 400° C results in surface segregation of the implanted 57 Co activity.
A Study on Hermetic Glass Sealing Using a Modified Direct Bonding Method
Authors: Ju B. K. , Ko C. G. , Lee Y. H. , Kang I. B. , White P. , Samaan N. , Haskard M. , Oh M. H. 
Published: June 2019

AbstractThis paper presents the process and experimental results about the improved initial bonding between #7740 glass and silicon wafers. We employed a modified initial bonding procedure, called by water-enhanced direct bonding(WDB) technique, and could obtain large initially-bonded area(≥ 95% of the whole wafer area) at room temperature and high interface energy (≥ 2,000 erg/cm2) through 250 °C post-annealing even though the glass wafer had high surface roughness. The main factors contributing to the wider bonded area and higher interface energy in the developed WDB process could be inferred the increase of chemical species (oxygen and hydroxyl groups) responsible for initial hydrogen bonding and conversion from hydroxyl bonds to siloxane bonds in the temperature range between room temperature and 250 °C.
Fabrication Processes and Characteristics of Microelectromechanical System Using PZT Films
Authors: Yoon Y. S. , Kim J. H. , Lim T. H. , Bonne U. A. , Schmidt A. M. , Polla D. L. 
Published: June 2019

AbstractThis paper gives a brief overview of fabrication problems and solutions for microelectromechnical system (MEMS) using PZT films based on surface micromachining techniques. In addition we report characteristics of PZT films on diagnostic test structures designed to test the new bottom electrode for MEMS. PZT(53/47) films were deposited by metalorganic decomposition on a 3″ silicon wafer with Pt/Ti/TiO2/Poly-Si/Si3N4 structure in order to fabricate piezoelectric cantilever beam microaccelerometers and uncooled infrared (IR) detectors. In order to investigate the feasibility of RuO2/Ru and Pt/RuO2 conducting layers as a new bottom electrode for piezoelectric MEMS, the piezoelectric constant (d33) of the PZT films on each bottom electrode was measured. Furthermore, we show the fraction of working top electrodes among 20 total electrodes according to electrode size to investigate the stability of PZT with different bottom electrodes. These results suggest that RuO2/Ru and Pt/RuO2 are possible for bottom electrodes of MEMS.
Pulsed Laser Deposition and Acoustic Property of Piezoelectric / Nonpiezoelectric Multilayer Films
Authors: Hu W. S. , Liu Z. G. , Chen Y-F. , Yu T. , Zhao H. W. , Hu X. B. , Liu X. , Wu R. X. 
Published: June 2019

AbstractPiezoelectric/nonpiezoelectric multilayer films were prepared by using pulsed laser deposition technique. The piezoelectric ZnO layers were completely (0001) textured and had the piezoelectric coefficient d33. The nonpiezoelectric (inactive) Al2O3 layers were amorphous and acted as good media for microwave and supersonic wave propagation. The periods were controlled by the deposition time in the range of 2.0 to 400 nm with the total period number of 4 to 30. In the multilayer films with ultrashort period of 2.1 nm, (0002) X-ray diffraction peak of ZnO layers was considerably broadened by the noncrystalline Al2O3 layers. In the multilayer films with short period of 6.4 nm, the diffraction peaks presented in small angle implies that the interfaces between layers were much flat and sharp, And in the multilayer films with long period, (0002) peak was very sharp, similar to the normal ZnO thin films. High frequency resonance was measured in the long-period multilayer films in the range of 1 - 20 GHz and higher frequency resonance is expected in the multilayer films with shorter period.
A New Technique for Measuring Poisson's Ratio of Mems Materials
Authors: Sharpe W. N. , Vaidyanathan K. R. , Yuan Bin , Edwards R. L. 
Published: June 2019

AbstractNew techniques and procedures for measuring Poisson's ratio of MEMS materials are presented. Tensile specimens of polysilicon that are 3.5 μm thick are pulled in a small test machine that has a linear air bearing to eliminate friction. Biaxial strain is measured directly by laser-based interferometry from four gold lines deposited on the specimen surface. The value of Poisson's ratio for vapor-deposited polysilicon is 0.22 +/- 0.01 as determined from 19 tests..
Photoconductivity in Vacuum Deposited Films of Silicon-Based Polymers
Authors: Okumoto H. , Shimomura M. , Minami N. , Tanabe Y. 
Published: June 2019

AbstractSilicon-based polymers with σconjugated electrons have specific properties; photoreactivity for microlithography and photoconductivity for hole transport materials. To explore the possibility of combining these two properties to develop photoresists with electronic transport capability, photoconductivity of polysilanes is investigated in connection with their photoinduced chemical modification. Increase in photocurrent is observed accompanying photoreaction of poly(dimethylsilane) vacuum deposited films. This increase is found to be greatly enhanced in oxygen atmosphere. Such changes of photocurrent can be explained by charge transfer to electron acceptors from Si dangling bonds postulated to be formed during photoreaction.
Hardening of Nickel Alloys by Ion Implantation of Titanium and Carbon
Authors: Myers S. M. , Follstaedt D. M. , Knapp J. A. , Christenson T. R. 
Published: June 2019

AbstractDual ion implantation of titanium and carbon was shown to produce an amorphous surface layer in annealed bulk nickel, in electroformed Ni, and in electroformed Ni7 5Fe 2 5. Diamond-tip nanoindentation coupled with finite-element modeling quantified the elastic and plastic mechanical properties of the implanted region. The amorphized matrix, with a thickness of about 100 nm, has a yield stress of approximately 6 GP and an intrinsic hardness near 16 GPa, exceeding by an order of magnitude the corresponding values for annealed bulk Ni. Implications for micro-electromechanical systems are discussed.
Impact of Electrodes on Gate Oxide Reliability: Examples from Isolation and Gate-Stack Processing
Authors: Chapek D. L. , Schuegraf K. F. , Thakur R. P. S. 
Published: June 2019

ABSTRACTThis paper discusses the challenges involved in improving gate oxide reliability for advanced integrated circuits through review of literature and other relevant data. We believe that gate oxide reliability improvements can be engineered by paying special attention to the process conditioning of the top and bottom electrode components of the thin oxide dielectric system in advanced ULSI technologies. We present examples that demonstrate the impact of process and materials on the performance of thin oxide. The data encompasses the effects of substrate, isolation, and top electrodes on gate oxide quality using a variety of methodologies to assess reliability.