bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microstructural Control of Internal Electromigration Failure in Narrow Al-Cu-Si Lines
Authors: Morris J.W. , Kim C. , Kang S.H. 
Published: April 2011

AbstractAl-Cu lines of submicron width ordinarily have quasi-bamboo microstructures that contain both bamboo grains and polygranular segments. The usual mechanism of internal electro-migration failure in such lines involves the formation of a transgranular void across a bamboo grain at the upstream end of a long, polygranular segment. The voiding is preceded by the depletion of Cu from both the polygranular segment and the upstream bamboo grain. At least three metallurgical mechanisms are available to inhibit this failure mechanism and improve the useful lifetime of the line. First, the line can be annealed after patterning to break up long polygranular segments. Second, the line can be aged at relatively low temperature to stabilize the distribution of Cu and retard its depletion from polygranular segments. Third, the line can be subjected to reverse currents to restore the distribution of Cu and provide a Cu reservoir. Each of these methods has been demonstrated in the laboratory environment.
Control of the Microstructure of Al Metallization by Graphoepitaxy
Authors: Van Den Homberg Marc J.C. , Alkemade P.F.A. , Hurd J.L. , Leusink G.J. , Radelaar S. 
Published: April 2011

AbstractMicrostructure is an important factor determining the lifetime of Al metallization lines. Deposition conditions, substrate material, alloying elements, and anneal treatments are the key parameters that influence microstructure. In this work we explore the use of graphoepitaxy as a tool for additional control over the grain structure of metallization lines. Onto a submicrometer topography in SiO2 (viz., a large number of parallel grooves), a pure Al film is grown by dc magnetron sputtering, followed by an in situ rapid thermal anneal. The topography of the annealed Al is investigated by cross section SEM. It is observed that if it is heated up to its melting point, Al fills the grooves and leaves the ridges between the grooves uncovered. X-Ray Diffraction, TEM, and Backscatter Kikuchi Diffraction are used to determine the global as well as the local crystallographic orientation of the grains in the quenched aluminum. The analyses are performed for various anneal and cool down treatments. Depending on the treatment, the Al lines in the grooves are either polycrystalline with an almost perfect (111) texture, or single crystalline but with a gradual change of 0.067°/μm in orientation. In the latter case, there is no preferred orientation. The single crystalline Al lines will be used as a starting point for the fabrication of model systems for fundamental electromigration studies.
The Electromigration and Failure Behaviour in Layered Tungsten Via Structures
Authors: Elliott L.J. , Spooner T. , Rose J.H. , Shuman R. 
Published: April 2011

AbstractThis work investigated the electromigration and failure behaviour of layered tungsten vias. It has long been recognized that the flux divergence caused by the tungsten-aluminum interface is an area of high reliability risk. In an attempt to lower this risk, several process experiments were initiated. The thickness (500Å, 800Å, and 1200Å), composition (TiN and Ti), and etch and rinse rates of the underlaying layers of the tungsten plugs were varied. Test structures consisting of a chain of eight M1 to M2 vias were placed on electromigration testing. Their variability in lifetimes, resistance vs. time characteristics and failure behaviour is reported. The fail sites were characterized using TEM analysis and FIB cross-sections. Based on these results process improvements for improved reliability were developed.
XRD and Tem Characterization of Cathodic MnO2 and Discharge Products in the Li-MnO2 Cell
Authors: Shao Y. , Hackney S.A. , Cornilsen B.C. 
Published: April 2011

ABSTRACTThe crystal structures of the undischarged, heat-treated electrolytic manganese dioxide (HEMD) and discharge products are characterized by high spatial resolution convergent beam electron diffraction (CBED). The results are compared with the x-ray diffraction (XRD) patterns characterized by broad, diffuse peaks. The CBED results for HEMD show that the starting cathodic material has the pyrolusite space group, but with a range of c/a ratios. The variability of the lattice parameter from grain to grain is found to coincide with the broadening on the low angle side of the XRD peaks. The CBED patterns of discharge products suggest a reduction range in c/a ratios and the formation of another phase.
Preparation and Properties of Manganese Dioxide/Polypyrrole Composites as an Active Material for Lithium Secondary Batteries
Authors: Kuwabata Susumu , Yoneyama Hiroshi 
Published: April 2011

ABSTRACTComposite powder of spinel LiMn2O4 and polypyrrole has been successfully prepared by injecting pyrrole into an HClO4 aqueous solution containing suspended LiMn2O4 powder which was used as an oxidizing agent for polymerization of pyrrole. The amount of LiMn2O4 in the composite increased with increasing the amount of the suspended oxide powder in the bath, whereas decrease in the amount of ClO4− dopant was observed. Charge-discharge tests of the resulting composite taken in a mixed solvent of propylene carbonate and 1,2-dimethoxyethane (1:1) containing 1 mol dm−3 LiClO4 revealed that polypyrrole of the composite worked well as an active material as well as a conducting network for the incorporated LiMn2O4 powder. Elemental analyses of the charged and discharged composites showed that Li+ cation alone was involved in the charge-discharge reactions of the LiMn2O4/PPy composite.
XPS Analysis of Lithium Surface and Modification of Surface State for Uniform Deposition of Lithium
Authors: Kanamura K. , Shiraishi S. , Takehara Z. 
Published: April 2011

ABSTRACTThe surface modification of lithium deposited at various current densities in propylene carbonate containing 1.0 ml dm−3 LiCIO4 was performed by addition of various amount of HF into the electrolyte, in order to investigate the effect of the HF addition on the surface reaction of lithium. XPS and SEM analyses showed that the surface state of lithium was influenced by the concentration of HF and the electrodeposition current. These two parameters are related to the chemical reaction rate of the lithium surface with HF and the electrodeposition rate of lithium, respectively. The surface modification was highly effective in suppressing lithium dendrite formation when the chemical reaction rate with HF was greater than the electrochemical deposition rate of lithium.
Advanced Catalytic Electrode Development for Nickel-Hydrogen Batteries
Authors: Coates D. K. , Grindstaff B. K. , Hoofnagle P. S. , Chiappetti D. P. 
Published: April 2011

ABSTRACTLow catalyst loading gas diffusion membrane electrodes have been developed for spaceflight qualified nickel-hydrogen (NiH2) batteries. These electrodes involve the use of new electrode designs and innovative manufacturing methods. Supported catalysts, mixed catalysts and alternative catalyst systems have been developed to decrease catalyst loading levels, and therefore reduce electrode cost, without reducing performance or reliability. This advanced electrode technology has currently accumulated more than 13,000 charge/discharge cycles in real-time, low-earth-orbit (LEO) testing. The technology has been incorporated into several nickel-hydrogen spaceflight programs including the TUBSAT B spacecraft, built by the Technical University of Berlin and launched in January of 1994 aboard a Russian Cyclone rocket.
Recent Progress in the Development of a Lightweight Nickel Electrode
Authors: Britton Doris L. 
Published: April 2011

ABSTRACTThe nickel-hydrogen (Ni-H2) cell is rapidly replacing nickel-cadmium (Ni-Cd) cell as the system of choice for aerospace applications where weight is crucial. The heavy-sintered nickel electrode used in this cell accounts for about 38% of the cell weight. The use of small diameter fiber nickel electrodes will reduce the weight and improve the specific energy of the state-of-the-art Ni-H2 cell by about 50%. One advantage of this small diameter nickel fiber material is the increase in the surface area available for the deposition of active material. Initial testing of this type of electrode is very promising. This electrode is also applicable to other nickel-based batteries, such as nickel-zinc, nickel-iron, and nickel-metalhydride, both for space and commercial applications.
Electrochemical Properties of Carbons Obtained From Precursors of Electrochemically Polymerized Polymers
Authors: Hashizume Kenichi , Tsutsup Miho , Kaneko Tomohiko , Otani Sugio , Yoshimura Susumu 
Published: April 2011

ABSTRACTElectrochemically polymerized polymers from pyrrole, fluoranthene and pyrene were heat-treated at temperatures between 600 to 3000 °C. The electrochemical properties of these heat-treated samples were examined by chronoamperometry using an electrolyte solution of IM LiClO4in propylene carbonate. Lithium doping capacities of carbons from fluoranthene and pyrrole polymer heat-treated at 3000 °C were 1.5 and 1.2 times that of the theoretical capacity of graphite as LiC6, respectively.
Characteristics of Mesophase Pitch-Based Carbon Fibers as Anode Materials for Lithium Secondary Cells
Authors: Tamaki Toshio 
Published: April 2011

ABSTRACTMesophase pitch-based Carbon Fibers(MPCF) have been investigated as anode materials for lithium secondary cells by examining their physical and electrochemical properties. Discharge capacity and initial charge-discharge efficiency of the materials were studied in relation to the heat treatment temperatures of MPCF. Carbon fiber which was heat treated at about 3,000’C gave the highest discharge capacity(over 300mAh/g), good efficiency (92%) and superior current capability (600mA/g). Carbon fiber heat treated at less than 1,000·C, also has superior discharge capacity(over 500mAh/g) at the first cycle, however efficiency was relatively low. Some of the relationships between structure of MPCF and electrochemical properties are discussed below.
Electronic/Ionic Conductivity and Oxygen Diffusion Coefficient af the Sr-Fe-Co-O System
Authors: Ma B. , Park J.-H. , Segre C. U. , Balachandran U. 
Published: April 2011

ABSTRACTOxides in the Sr-Fe-Co-O system exhibit both electronic and ionic conductivities. Recently, the Sr-Fe-Co-O system attracted great attention because of its potential to be used for oxygen-permeable membranes that can operate without electrodes or external electrical circuitry. Electronic and ionic conductivities of two compositions of the Sr-Fe-Co-O system, named SFC-1 and SFC-2, have been measured at various temperatures. The electronic transference number is much greater than the ionic transference number in SFC-1, whereas the electronic and ionic transference numbers are very similar in SFC-2. At 800°C, the electronic and ionic conductivities are ≈76 and ≈4 S•cm−1, respectively, for SFC-1; whereas, for SFC-2, the electronic and ionic conductivities are ≈10 and∼1S•cm−1, respectively. By performing a local fitting to the equation σ • T = Aexp(-Ea/ kT), we found that the oxide ion activation energies are 0.92 and 0.37 eV, respectively, for SFC-1 and SFC-2. The oxygen diffusion coefficient of SFC-2 is ≈ 9 x 10−7cm2/sec at 900°C.
Growth of Vacancy Clusters During Post-Irradiation Annealing of Ion Implanted Silicon,
Authors: van Veen A. , Schut H. , Rivera A. , Fedorov A.V. 
Published: April 2011

AbstractAnnealing experiments of deuterium implanted silicon have been performed while positron beam analysis was used for monitoring the cavity growth. The experiments indicate up to annealing temperature 500° C similar defect evolution for both the low dose of 1016 cm-2 as for a 3 times higher dose. At this temperature the deuterium stabilized vacancy clusters dissociate and only in the case of the high dose micro-cavities are formed. Monte Carlo simulations of vacancy cluster growth in silicon based on vacancy cluster dissociation energies, calculated with the Stillinger Weber potential, have been performed. The results indicate that for low initial defect concentrations vacancy clusters might be hindered to grow because the vacancy binding energy of the clusters does not increase monotonically with the cluster size. Only a high concentration guarantees that growth barriers will be overcome.
Effects of Arsenic Deactivation on Arsenic-Implant Induced Enhanced Diffusion in Silicon
Authors: Dokumaci O. , Law M.E. , Krishnamoorthy V. , Jones K.S. 
Published: April 2011

AbstractThe enhanced diffusion of boron due to high dose arsenic implantation into silicon is studied as a function of arsenic dose. The behavior of both the type-V and end-of-range loops is investigated by transmission electron microscopy (TEM). The role of arsenic deactivation induced interstitials and type-V loops on enhanced diffusion is assessed. Reduction of the boron diffusivity is observed with increasing arsenic dose at three different temperatures. The possible explanations for this reduction are discussed.
Growth of Si1-x.Snx Layers on Si by Ion-Beam-Induced Epitaxial Crystallization (Ibiec) and Solid Phase Epitaxial Growth (Speg)
Authors: Kobayashi N. , Hasegawa M. , Hayashi N. , Katsumata H. , Makita Y. , Shibata H. , Uekusa S. 
Published: April 2011

AbstractSynthesis of metastable group-IV binary alloy semiconductor thin films on Si was achieved by the crystalline growth of Si1-xSnx layers using Sn ion implantation into Si(100) followed either by ion-beam-induced epitaxial crystallization (IBIEC) or solid phase epitaxial growth (SPEG). Si(100) wafers were implanted at room temperature with 110keV 120Sn ions to a dose of 1×1016 cm-2 (x=0.029 at peak concentration) and 2x1016 cm-2 (x=0.058 at peak concentration). By this process about 90nm-thick amorphous Si1-xSnx and about 30nm-thick deeper amorphous Si layers were formed. IBIEC experiments performed with 400keV Ar ions at 300–400°C have induced an epitaxial crystallization of the amorphous alloy layers up to the surface and lattice site occupation of Sn atoms for samples with the lower Sn concentration (LC). XRD analyses have revealed a partial strain compensation for the crystallized layer. Samples with the higher Sn concentration (HC) have shown an epitaxial crystallization accompanied by defects around the peak Sn concentration. SPEG experiments up to 750°C for LC samples have shown an epitaxial crystallization of the fully strained alloy layer, whereas those for HC samples up to 750°C have revealed a collapse of the epitaxial growth around the interface of the alloy layer and the Si substrate. Photoluminescence (PL) emission from both IBIEC-grown and SPEG-grown samples with the lower Sn concentration has shown similar peaks to those by ion-implanted and annealed Si samples with intense I1 or I1-related (Ar) peaks. Present results suggest that IBIEC has a feature for the non-thermal equilibrium fabrication of Si-Sn alloy semiconductors.
Structural Disorder in Hard Amorphous Carbon Films Implanted with Nitrogen Ions
Authors: Freire F.L. , Franceschini D.F. , Achete C.A. , Brusa R.S. , Mariotto G. , Karwasz G. P. , Canteri R. 
Published: April 2011

AbstractHard amorphous hydrogenated carbon films deposited by self-bias glow discharge were implanted at room temperature with 70 keV-nitrogen ions at fluences between 2.0 and 9.0×1016 N/cm2. The implanted samples were analyzed by Raman spectroscopy, SIMS and positron annihilation spectroscopy (Doppler broadening technique with the determination of the parameter S. For samples implanted with 2.0x1016 N/cm2 the S parameter follows the vacancies depth profile predicted by Monte Carlo simulation. For higher fluences we observed a reduction in the measured value of S. This result is discussed in terms of both hydrogen loss and structural modifications(increase of disorder at local scale and of the number of graphitic domains) induced in the carbon film by ion implantation.
Bombarding Effects of Gas Cluster Ion Beams on Sapphire Surfaces; Characteristics of Modified Layers and their Mechanical and Optical Properties
Authors: Takeuchi D. , Matsuo J. , Yamada I. 
Published: April 2011

AbstractGas cluster ions contain tens, hundreds or even more than thousands of atoms or molecules as ionized particles. It has been shown that the bombarding effects of gas cluster ions on solid surfaces are quite different from those by monomer ions and involve unique material processing characteristics. In order to make clear the bombarding effects, a study of surface modification of sapphire by Ar and CO2 gas cluster ion beams has been performed.
Thickness of the damaged layer and surface roughness produced on sapphire depends strongly on cluster ion energy. Damage layer thickness on a sapphire surface bombarded by 150 keV clusters with average size of about 3000 atoms was 40Å. No significant difference was observed in IR transmittance after cluster bombardment. Mechanical properties of sapphire surfaces can be changed by cluster irradiation at a dose of 1011 ions/cm2.
Suspended Conductive Polymer Bridges From Ion Implanted Polymers
Authors: Kaufmann James , Moss Mary G. , Wang Yongqiang , Giedd Ryan E. 
Published: April 2011

AbstractPhotolithographic processing capabilities of ion implanted polymer (IIP) films spin-coated onto silicon substrates were evaluated to determine the optimum conditions for producing stable, small geometry devices. Films which had a thickness approximately equivalent to or less than the mean range of ions in the polymer had good quality and stability, and could be patterned without change of conductivity to form small geometry resistors with dimensions of 10 to 50 micrometers. Sixteen-element, packaged resistor arrays were produced from ion implanted poly(styrene-acrylonitrile) films. High quality films with resistivities from 400 ohms/square to 10 megohms/square could be produced by the ion implantation technique. Suspended conducting polymer bridges were formed from IIP resistors by etching of a sacrificial layer underlying the IIP film. Electrical and mechanical properties of the bridges are presented.
Structural and Optical Properties of Rare-Earth Doped Lithium Niobate Waveguides Formed by Mev Helium Implantation
Authors: Herreros B. , Lifante G. , CussÓ F. , Kling A. , Soares J.C. , Da Silva M.F. , Townsend P.D. , Chandler P.J. 
Published: April 2011

AbstractResults of investigations of optical waveguides formed by high energy helium implantation into lithium niobate codoped with 5 mol% MgO and 1 mol% Tm3+ or 1 mol% Er3+ are reported. A comparative study of structural and luminescence properties between implanted and untreated samples has been performed by means of Rutherford backscattering (RBS) combined with channeling and photoluminescence methods, respectively in order to investigate residual lattice damage and the incorporation of the optical active rare earths. For the case of Tm a full substitutional incorporation on the lithium site and a high crystal quality in both bulk and implanted waveguide material has been found. For Er doped lithium niobate the channeling results show a fraction of Er randomly incorporated or forming precipitates and a deterioration of the waveguide's lattice. The optical investigations show in both cases only a slight broadening of the emission lines of the rare earths in the waveguides compared to the bulk material.
Nanocrystal Formation Via Yttrium Ion Implantation into Sapphire
Authors: Hunt E. M. , Hampikian J. M. , Poker D. B. 
Published: April 2011

AbstractIon implantation has been used to form nanocrystals in the near surface of single crystal A12O3. The ion fluence was 5 x 1016 Y+/cm2, and the implant energies investigated were 100, 150, and 170 keV. The morphology of the implanted region was investigated using transmission electron microscopy, x-ray energy dispersive spectroscopy, Rutherford backscattering spectroscopy and ion channeling. The implantation causes the formation of an amorphous surface layer which contains spherical nanosized crystals with a diameter of ∼13 nm. The nanocrystals are randomly oriented and exhibit a face-centered cubic structure with a lattice pmeter of ∼4.1 A ± .02 A. Preliminary chemical analysis shows that these nanocrystals are rich in aluminum and yttrium and poor in oxygen relative to the amorphous matrix.
Residual Stress Control by Ion Beam Assisted Deposition
Authors: Was G. S. , Jones J. W. , Parfitt L. , Kalnas C.E. , Goldiner M. 
Published: April 2011

AbstractThe origin of residual stresses were studied in both crystalline metallic films and amorphous oxide films made by ion beam assisted deposition (IBAD). Monolithic films of AI2O3 were deposited during bombardment by Ne, Ar or Kr over a narrow range of energies, E, and a wide range of ion-to-atom arrival rate ratios, R and were characterized in terms of composition, thickness, density, crystallinity, microstructure and residual stress. The stress was a strong function of ion beam parameters and gas content and compares to the behavior of other amorphous compounds such as MoSix and WS12.2 With increasing normalized energy (eV/atom), residual stress in crystalline metallic films (Mo, W) increases in the tensile direction before reversing and becoming compressive at high normalized energy. The origin of the stress is most likely due to densification or interstitial generation. Residual stress in amorphous films (Al2O3, MoSix and WSi2.2) is initially tensile and monotonically decreases into the compressive region with increasing normalized energy. The amorphous films also incorporate substantially more gas than crystalline films and in the case of Al2O3 are characterized by a high density of voids. Stress due to gas pressure in existing voids explains neither the functional dependence on gas content nor the magnitude of the observed stress. A more likely explanation for the behavior of stress is gas incorporation into the matrix, where the amount of incorporated gas is controlled by trapping.
Low-Energy Deposition of High-Strength AI(O) Alloys From an ECR Plasma
Authors: Barbour J.C. , Follstaedt D.M. , Knapp J.A. , Marshall D.A. , Myers S.M. , Lad R.J. 
Published: April 2011

References and AcknowledgmentsLow-energy deposition of AI(O) alloys from an electron cyclotron resonance (ECR) plasma offers a scaleable method for the synthesis of thick, high-strength AI layers. This work compares alloy layers formed by an ECR-O2 plasma in conjunction with AI evaporation to O-implanted AI (ion energies 25–200 keV), and it examines the effects of volume fraction of AI2O3 phase and deposition temperature on the yield stress of the material. TEM showed the AI(O) alloys contain a dense dispersion of small y-AbOa precipitates (∼1 nm) in a fine-grain (10–100 nm) fee AI matrix when deposited at a temperature of ∼100°C, similar to the microstructure for gigapascal-strength O-implanted AI. Nanoindentation gave hardnesses for ECR films from 1.1 to 3.2 GPa, and finite-element modeling gave yield stresses up to 1.3 ± 0.2 GPa with an elastic modulus of 66 GPa ± 6 GPa (similar to pure bulk AI). The yield stress of a polycrystalline pure AI layer was only 0.19+0.02 GPa, which was increased to 0.87+0.15 GPa by implantation with 5 at.% O.
Hydrogen Etching Effects During Plasma Doping Processes and Impact on Shallow Junction Formation
Authors: Qin Shu , Bernstein James D. , Chan Chung 
Published: April 2011

AbstractHydrogen etching effects in plasma ion implantation (PII) doping processes alter device structure and implant dopant profile and reduce the retained implant dose. This has particular relevance to the shallow junction devices of ultra large scale integrated circuits (ULSI). Hydrogen etching of semiconductor materials including Si, poly-Si, SiO2, Al, and photoresist films have been investigated. The effects of varying different PII process parameters are presented. The experimental data show that the spontaneous etching by hydrogen radicals enhanced by ion bombardment is responsible for the etching phenomena. A computer simulation is used to predict the as-implanted impurity profile and the retained implant dose for a shallow junction doping when the etching effect is considered.