bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Self-Aligned Silicide Process for Thin Silicon-on-Insulator MOSFETs and Bulk MOSFETs with Shallow Junctions
Authors: Cohen G. M. , Cabral C. , Lavoie C. , Solomon P. M. , Guarini K.W. , Chan K.K. , Roy R.A. 
Published: April 2011

AbstractWe discuss a modified self-aligned silicide (salicide) process that uses a silicon cap to reduce the substrate silicon consumption by 50% as compared with a conventional salicide process. We have used a metal-silicon mixture to form the metal-rich phase reliably in the first anneal. After etching the unreacted mixture we deposit a silicon cap. This forces the metal to react with the silicon cap as well as with the substrate during the second anneal, thus minimizing silicon consumption from the substrate. The unreacted portion of the silicon cap is selectively etched, leaving a structure with a raised source and drain. We expect this process to be useful for forming silicide on shallow junctions and thin SOI films, where silicon consumption is constrained.
Neutron Irradiation-Induced Dimensional Changes in MEMS Glass Substrates
Authors: Allred Clark L. , Borenstein Jeffrey T. , Hobbs Linn W. 
Published: April 2011

AbstractA study is made of radiation-induced expansion/compaction in Pyrex and Hoya SD-2 glasses, which are used as substrates for MEMS devices. Glass samples were irradiated with a neutron fluence composed primarily of thermal neutrons, and a flotation technique was employed to measure the resulting density changes in the glass. Transport of Ions in Matter (TRIM) calculations were performed to relate fast (∼1 MeV) neutron atomic displacement damage to that of boron thermal neutron capture events, and measured density changes in the glass samples were thus proportionally attributed to thermal and fast neutron fluences. The trend for strain with thermal neutron fluence (n/cm2) was found to be a linear compaction of -2.8×10−20 for Pyrex and -1.0×10−21 for Hoya SD-2. For fast neutron fluence, the trend for strain was also linear: -6.1×10−21for Pyrex and -7.9×10−22 for Hoya SD-2. The measured radiation-induced compaction of Pyrex is found to agree with that of previous studies. To our knowledge, this work represents the first study of compaction in Hoya SD-2 with neutron fluence. Hoya SD-2 is of considerable importance to MEMS, owing to its close thermal expansivity match to silicon from 25-500 C.
Issues with Gold Electroplating for Microelectromechanical System Applications
Authors: Kondoleon Caroline A. , Marinis Thomas F. 
Published: April 2011

AbstractElectro-plated gold films are used extensively in packaging of MEM sensors to make connections to signal conditioning electronics. Over the past two years, production lots of gold plated substrates, procured from various vendors, failed an accelerated aging qualification test. In this test, 0.0025 [mm] diameter aluminum wires were ultrasonically welded to the film, aged at 120°C for 48 hours, and then pulled to destruction. The criterion for passing this test was that the wires should break both before and after aging. In the defective lots, the wires lifted off of the gold film after aging. Analysis of these defective films by SEM, Auger, and TOF-SIMS suggested that residues, deposited from the plating bath, concentrated beneath the bond as the gold and aluminum reacted to form an inter-metallic compound during aging. A combination, etch and cleaning treatment was developed for defective substrates, which removed a sufficient amount of residues from the gold to pass the qualification test.
Microstructuring of Silica and Polymethylmethacrylate Glasses by Femtosecond Irradiation for MEMS Applications
Authors: Juodkazis Saulius , Yamasaki Kazuhiko , Marcinkeviĉius Andrius , Mizeikis Vygantas , Matsuo Shigeki , Misawa Hiroaki , Lippert Thomas 
Published: April 2011

AbstractWe report the fabrication of complex 3D microstructures in silica and polymethyl- methacrylate glass by a combination of femtosecond laser microfabrication and chemical wet etching techniques. It is demonstrated that fabrication of interconnected network of channels having lengths of about 200 νm, and diameters as small as 10 νm is possible due to the enhanced etching selectivity (typically 20 - 60) in the laser-irradiated regions. Thus, it becomes feasible to form 3D micro-fluidic and photonic crystal structures in transparent glass-like materials using this approach. In addition, preliminary results on microstructuring of rubber are presented.
Characterizing Transport Current Defects in 1-cm-Wide YBa2Cu3O7-δ Coated Conductors
Authors: Brown G. W. , Hawley M. E. , Peterson E. J. , Coulter J. Y. , Dowden P. C. , Arendt P. N. , Foltyn S. R. , Mueller F. M. 
Published: April 2011

ABSTRACTWe have used a low temperature magnetic imaging system to determine current pathways in 5 cm long “good” and “bad” regions of a 1-cm-wide YBa2Cu3O7-δ coated conductor. The good and bad regions were identified with 4 point probe measurements taken at 1 cm intervals along the tape length. The current density map from the good region showed the expected edge peaked structure, similar to that seen in previous work on high quality test samples grown on single crystal substrates. The structure was also consistent with theoretical understanding of thin film superconductors where demagnetizing effects are strong. The maps from the bad region showed that the current was primarily confined to the right half of the sample. The left half carried only a small current that reached saturation quickly. Effectively halving the sample width quantitatively explains the critical current measured in that section. Spatially resolved x-ray analysis with 1 mm resolution was used to further characterize the bad section and suggested an abnormally large amount of a-axis YBCO present. This may be the result of non-uniform heating leading to a low deposition temperature in that area.
In-situDeposition of Superconducting MgB2 Films
Authors: Stelmashenko N. , Yates K. A. , Tsaneva V. N. , Kambara M. , Cardwell D. A. , Blamire M. G. 
Published: April 2011

ABSTRACTThe discovery of superconductivity in MgB2 has been followed by many papers reporting attractive thin film properties. In most cases these have involved the deposition of precursor films followed by in-situ or ex-situ post annealing in a Mg-rich atmosphere. Although simple device structures have been fabricated from such films, it is desirable for a number of reasons that a heterostructure device technology be developed. Heterostructure growth is likely to require in-situ growth, preferably without post-annealing. To achieve this, low oxygen and high Mg background pressures are required in the vicinity of the sample. By using a novel heater geometry we have been able to grow superconducting MgB2 films from Mg-rich targets at temperatures below 500 °C. This paper reports the growth method, and structural and electrical characterization of the films.
Observation of Vortices and Columnar Defects by 1-MV Lorentz Microscopy II
Authors: Kamimura O. , Kasai H. , Matsuda T. , Harada K. , Tonomura A. , Okayasu S. , Sasase M. , Nakayama Y. , Shimoyama J. , Kishio K. , Hanaguri T. , Kitazawa K. 
Published: April 2011

ABSTRACTTwo types of shape and contrast features of superconducting vortices in a Lorentz micrograph were obtained by the newly developed 1-MV field-emission transmission electron microscope on a Bi2Sr2CaCu2O8+8(Bi-2212) thin specimen containing tilted columnar defects. The shape and contrast features could be consistently interpreted by the simulation that some vortices were pinned along tilted columnar defects and others were unpinned. The interesting property for temperature change of vortex core inside the material was also observed.
Intrinsic Josephson Junctions on High-quality BSCCO-2212/2223 Superlattice Thin Films Grown by MOCVD
Authors: Endo K. , Sato H. , Yoshizawa T. , Abe K. , Itoh J. , Kajimura K. , Akoh H. 
Published: April 2011

ABSTRACTWe report on the successful preparation of intrinsic Josephson junctions on high-quality BSCCO-2212/2223 superlattice thin films grown by MOCVD. The surface of as-grown films was very smooth with the roughness of the order of a half unit cell. Mesas were effectively structured on the film by the liquid-nitrogen-cooled dry etching method. A typical I-V characteristic in the c-axis direction of a BSCCO film shows the hysteresis and multiple resistive branches. The number of branches is consistent with that of junctions calculated from the height of a mesa structure. This indicates that BSCCO-2212/2223 superlattice films consist of a series array of S(CuO2 bilayer) / I(SrO, BiO layers) / S(CuO2 trilayer) junction. The formation of stacked Josephson junctions was also confirmed by the temperature dependence and the magnetic field dependence of Ic.
Effect of High Magnetic Field during Melt-Solidification Process on Crystal Alignment of REBCO Bulk
Authors: Yamagiwa R. , Horii S. , Eto H. , Otzschi K. , Shimoyama J. , Kishio K. 
Published: April 2011

ABSTRACTDisk-shaped samples of REBa2Cu3Oy ( RE123, RE = Y, Ho ) with 40%-by-molar RE2BaCuO5 (RE211, same RE of RE123 ) were melt-solidified without seeding under various magnetic fields (μ0Ha = 0 ˜ 8 T) and at various cooling rates ( Cr = 5.0, 10.0°C/h) in ambient atmosphere. Crystal alignment was evaluated by the X-ray diffraction, magnetization measurement using a SQUID magnetometer and observation of microstructure using a scanning electron microscope and a polarizing microscope. The melt grown RE123 crystals were c-axis-aligned under magnetic fields parallel to the applied field, (Ha), while the effect of alignment were systematically changed by the conditions of cooling rate and RE elements and the magnitude of Ha. The best c-axis-aligned sample showed that the value of anisotropy ( where the ratio of ΔMH//Ha /ΔMH⊥Ha) was approximately 20 at 85K and at μ0H = 0.3 T for the condition of RE = Y, Cr = 5.0°C/h, μ0Ha = 8 T.
Phase Relationships and Phase Formation in the System BaF2-BaO-Y2O3-CuOx-H2O
Authors: Wong-Ng W. , Cook L. P. , Suh J. , Levin I. , Vaudin M. , Feenstra R. , Cline J. P. 
Published: April 2011

ABSTRACTThe interplay of melting equilibria and reaction kinetics is important during formation of the Ba2YCu3O6+x (Y-213) phase from starting materials in the quaternary reciprocal system Ba,Y,Cu//O,F. For experimental investigation of the process we used a combination of differential thermal analysis (DTA) for study of melting equilibria, and in-situ high-temperature x-ray diffraction (HTXRD) for study of the phase formation and reaction kinetics. DTA investigation of compositions spaced along compositional vectors extending from the oxide end to the fluoride end of the reciprocal system have given evidence of low melting liquids (∼600 °C) near the fluorine-rich end. Work is continuing to determine whether similar thermal events observed in the interior of the system also indicate low temperature liquids, and on the extent to which low-melting liquids could be involved in Y-213 phase formation. HTXRD investigations have been initiated on the conversion of 0.3 μm and 1.0 μm thick BaF2-Y-Cu precursor films to Y-213 in the presence of water vapor. Preliminary results indicated that the thickness of film has a strong influence on the texture of the Y-213 film: a 0.3 μm film showed mainly (001) texture, whereas a 1.0 μm film showed a greater volume fraction of (h00) texture. While the HTXRD method cannot directly reveal the presence of liquid, we are working to combine DTA and HTXRD data for a unified picture of Y-213 phase formation during the “BaF2 ex-situ” process for coated-conductor fabrication.
Theoretical Considerations for Finding New Thermoelectric Materials
Authors: Singh David J. 
Published: April 2011

ABSTRACTThis paper reviews the connections between the transport properties underlying the thermoelectric performance of a material and microscopic quantities, particularly as they may be obtained from first principles calculations. These are illustrated using examples from work on skutterudites. The results are used to suggest yet to be explored avenues for achieving higher thermoelectric performance within this class of materials.
Synthesis and Properties of Lead Selenide Nanocrystal Solids
Authors: Chen Feng , Stokes Kevin L. , Zhou Weilie , Fang Jiye , Murray Christopher B. 
Published: April 2011

ABSTRACTWe present results of our investigation of the synthesis, structural properties and electrical transport properties of lead selenide (PbSe) nanoparticle-derived solids. Stable colloidal solutions containing crystalline PbSe particles with sizes on the order of 5-10 nm were synthesized using an organometallic lyothermal growth method in high-temperature organic solvents (100∼200 °C). The nanoparticle powders have been characterized by X-ray scattering (WAXS/SAXS), electron microscopy and optical absorption. Thin lms were formed by controlled precipitation of the nanoparticles from solution onto insulating substrates. Electrical resistance (R) and Seebeck coecient (S) for conductive PbSe lms from dierent annealing conditions were studied and compared. We were able to obtain conductive PbSe lms from colloids by low temperature annealing which did not disturb the nanoparticle self-assembly.
Multinuclear NMR and Powder X-ray Diffraction Studies of Si and Sn Clathrates of Alkali Metals: Vacancies, Disorder and Knight Shifts
Authors: Ferguson Michael J. , Moudrakovski Igor L. , Ratcliffe Christopher I. , Tse John S. 
Published: April 2011

ABSTRACTThe Structure I type binary metal clathrates of K/Si, Rb/Si and Cs/Sn have been synthesised and studied by powder X-ray diffraction and solid state NMR. Rietveld analysis shows that in all three materials some of the cages are empty, and that in the Cs/Sn clathrate there are vacancies in the Sn framework. The NMR results yield Knight shifts for 29Si and 39K and confirm that the Cs/Sn clathrate is not conducting. Many of the features of the NMR spectra can be understood in terms of the distributions of atom vacancies.
Experimental Thermopower of Quantum Wires
Authors: Vedernikov M. V. , Uryupin O. N. , Goltsman B. M. , Ivanov Yu. V. , Kumzerov Yu. A. 
Published: April 2011

ABSTRACTExperimental investigation of thermoelectric properties of nanowires with diameter of about 5 nm was carried out. Chrysotile asbestos (a natural mineral) was used for a sample preparation. Its nano-sized channels were filled under pressure by melted InSb or Te. The measurements showed that temperature dependences of electrical resistance and thermopower of produced quantum wires differ considerably from corresponding dependences of bulk materials. It is possible to conclude that the results obtained are better described by Lattinger liquid model than by usual Fermi gas one.
Formation, Crystal Structure and Physical Properties of Novel Thermoelectric Skutterudites: EuyFe4−xNixSb12
Authors: Grytsiv Andriy , Rogl Peter , Berger Stefan , Paul Christoph , Bauer Ernst , Godart Claude , Saccone Adriana , Ferro Ricardo , Kaczorowski Darek 
Published: April 2011

ABSTRACTQuantitative X-ray powder Rietveld refinements for a series of alloys from the solid solution EuyFe4−xNixSb12, synthesized by argon arc-melting followed by long term annealing, established in all cases isotypism with the partially filled skutterudite-type structure, LaFe4P12. The Eucontent of the samples was determined from the combined data obtained results of Rietveld refinements and electron microprobe measurements. These investigations confirmed a systematic trend for the Eu-occupancy y in the parent lattice, revealing a gradual decrease of the maximum Eu-content from practically full occupancy, y = 0.83, in Eu0.83Fe4Sb12 to y ∼ 0.5 for Eu∼0.5Fe2Ni2Sb12. Eu0.83Fe4Sb12 orders magnetically below 84 K and the transition temperature decreases as a function of Fe/Ni substitution. As a further consequence of the Fe/Ni substitution electronic transport crosses over from a hole conductivity regime into electron dominated behaviour. Concomitantly, the transition metal exchange increases the Seebeck coefficient significantly, hence the figure of merit enhances.
BN protective coating for high temperature applications
Authors: Bathe Ravi , Vispute R.D. , Habersat Daniel , Takeuchi Ichiro , Sharma R.P. , Venkatesan T. , Zheleva T.S. , Jones Ken 
Published: April 2011

AbstractWe report on the fabrication, characterization, and processing of boron nitride films for use in high temperature applications such as field passivation, capping layers for thermal annealing of SiC, and protecting metallic filaments from their working environments. The BN films have been fabricated by pulsed laser deposition and spray techniques. The deposited films were characterized by X-ray Diffraction, Fourier Transform Infrared Spectroscopy, Ultraviolet-Visible Spectroscopy, Rutherford Backscattering Spectrometry and Transmission Electron Microscopy. The BN films deposited in the temperature range of 200-500°C have been found to be poorly crystalline, whereas the films fabricated above 600°C have been found to be microcrystalline. The as-deposited films were annealed at various temperatures ranging from 900°C to 1700°C in order to densify the films and study the applicability of the coatings. An AlN buffer layer was also applied in a few cases to improve chemical bonding with the substrate. Adhesion of the films with the heater components was greatly improved for high temperature annealed samples due to good interfacial bonding with the substrate material. Our results on the properties of BN films with an emphasis on characterization, processing, and implications for high temperature applications are discussed.
Bio-compatible Thin Films on Rare Earth Based Permanent Magnets
Authors: Vasilescu Ecaterina , Drob Paula , Raducanu Doina , Angelescu Lucia , Iliuc Constantin 
Published: April 2011

AbstractThe item of the paper is focussed on some bio-compatible coatings for rare earth based permanent magnets, which are used as dental materials for prosthetic devices as retention units. The studied alloy belongs to Nd-Fe-B system with some Dy and Al content. The double-layer coatings had different chemical compositions; first layer: Ag30-Cr70, Co30-Cr70, Stainless Steel and the second layer: titanium nitride (TiN). Data about corrosion behavior, wear resistance and adhesion are presented. The corrosion resistance of these coatings was tested in artificial saliva, using electrochemical potentiostatic and potentiodynamic polarization techniques. The stability in the corrosion media, the localized corrosion susceptibility and the corrosion rates were determined. It resulted that the Nd30-Dy5-Fe-Al0.4-B alloy with Ag30-Cr70 + TiN film is very stable in artificial saliva. The wear behavior of the coatings in different conditions of contact and load was tested, also. The adhesion was determined by scratching test.
Structural and Tribological Properties of TiC/C/Ag Coatings in Vacuum and Ambient Environments
Authors: Endrino Jose L. , Nainaparampil Jose J. , Krzanowski James E. 
Published: April 2011

AbstractTiC/C/Ag coatings were deposited by magnetron sputtering pulsed laser deposition (MSPLD) combining sputtering from a custom made Ti-Ag (60:40) target with the ablation of carbon. Energy disperse spectroscopy (EDS) was used to determine the elemental composition, and x-ray diffraction (XRD) and cross-sectional scanning electron microscopy (XSEM) to examine the structure of the films. Hardness and reduced modulus measurements were acquired using a nanoindentation technique. The pin-on-disk friction test was used to study the friction behavior of the deposited samples in high vacuum and ambient conditions. Variations in the laser energy and the power of the sputtering gun yielded a set of samples with carbon content that ranged from 15.0 to 95.6 percent. The hardest samples with the highest reduced modulus were those with a moderate carbon content and that were shown to form a titanium carbide phase. Tribological results indicated that there is an optimum composition of a TiC/C/Ag coating (~25 at.% carbon) for which it can be reversible and provide lubrication in both ambient and vacuum.
Tribology of Material Contacts under Dynamic Loading, Studied by Electrical Resistance Measurement
Authors: Luo Xiangcheng , Chung D.D.L. 
Published: April 2011

AbstractThe tribology of material contacts under cyclic compression in the direction perpendicular to the plane of the contact was studied by measurement of the contact electrical resistivity of the contact during the dynamic loading. The real-time monitoring allowed observation of both reversible and irreversible effects. The material contacts studied were those involving steel, carbon fiber polymer-matrix composite, cement mortar and graphite, due to their relevance to fastening, concrete structures, electric brushes and electrical pressure contacts. Correlation was made between the contact resistivity and the occurrence of elastic/plastic deformation at asperities. The interfacial structure was found to depend on the stress and the loading history.
Ordering Effect of Lithium Ions in a Self-Assembled Hybrid System
Authors: Retuert P.J. , Fuentes S. , González G. , Yazdani-Pedram M. 
Published: April 2011

AbstractBy blending 3-aminopropyl-siloxane oligomers (pAPS) with chitosan (CHI) self-assembled hybrid films have been obtained. The influence of the incorporation of LiClO4 on the morphology of these transparent and flexible hybrid films has been studied. It was found that when this salt is added in amounts slightly over the limit of the maximal homogeneous incorporation a process of anisotropical crystallization begins. For a hybrid with composition CHI/pAPS/LiClO4 = 0.6/1/0.8M, Video-Enhanced Differential Interference Contrast microscopy (VEC-DIC) of the first three layers of the films showed that each layer have oriented patterns with angles of exactly 60 degrees between the planes. These results in combination with FTIR analysis of the products indicate that lithium ions behave as strong structure directing agent. This system can be considered as a biomimetic model for biomineralization processes. An interaction scheme comprising the components of this hybrid system is proposed.
Rod-like Dinuclear Ruthenium Complexes for Dye-sensitized Photovoltaics
Authors: Mosurkal Ravi , He Jin-An , Kumar Jayant , Li Lian , Walker John , Samuelson Lynne 
Published: April 2011

ABSTRACTRuthenium complexes with tridentate terpyridine type ligands have many structural advantages over the complexes with bipyridine ligands. Polynuclear ruthenium complexes prepared using these terpyridine ligands bridged with phenylene rings are potential candidates for photosensitization in dye-sensitized photovoltaic cells. In this study, we have carried out synthesis, characterization and theoretical modeling of rigid, rod-like homometallic dinuclear ruthenium complexes using terpyridine and bipyridine ligands. The photophysical and photovoltaic properties have been investigated. These supramolecular dyes are found to be efficient photosensitizers in dye-sensitized photovoltaic cells when a liquid electrolyte is employed.