bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of the Microscopic Nature of Cu-Pairs in Silicon
Authors: Istratov A.A. , Heiser T. , Hieslmair H. , Flink C. , Weber E.R. 
Published: April 2011

AbstractStudies of the thermal dissociation kinetics of Cu-pairs in p-type silicon revealed that the dissociation energy of the pairs is 1.02±0.07 eV, which is twice as large as the binding energy of a coulombically bound donor-acceptor pairs formed by singly charged ions placed on nearest neighbor <111> sites. The dependence of the hole emission rate from the center versus electric field in the depletion region was found to be much weaker than predicted by the Pool-Frenkel law. On the other hand, the polarization potential describing emission from a neutral impurity gave a satisfactory fit to the experimental data. It is concluded that the Cu-pair is a donor with either covalent or mixed type of bonding of interstitial and substitutional copper atoms.
Solutions to Gate Oxide Integrity on TFSOI Substrates Caused by PMOS Threshold-Voltage Implant
Authors: Hong S. Q. , Wetteroth T. , Wilson S. R. , Steele B. , Schroder D. K. 
Published: April 2011

AbstractDue to the lack of effective gettering, gate oxide on thin-film-silicon-on-insulator (TFSOI) substrates is much more sensitive than its bulk Si counterpart to process damage during device fabrication, especially prior to gate oxide growth. Presented in this paper as a typical example is the severe oxide degradation caused by PMOS threshold-voltage implant. Several approaches to circumvent this problem are explored, such as Vt implant without sacrificial oxide (sacox), low temperature anneal before sacox removal, or implementation of lateral gettering. As a result of these efforts, a significant improvement in gate oxide integrity is achieved with increased oxide breakdown voltages and charge-to-breakdowns, as well as a reduction in oxide charge trapping. This work also demonstrates the feasibility of achieving bulk-comparable gate oxide on TFSOI substrates.
Effect of Oxygen on the Formation of Dryetching Damage Introduced into Si-Substrate
Authors: Hamada Koji , Kitano Tomohisa 
Published: April 2011

AbstractThis paper reports the effects of oxygen in a Si substrate on dryetching damage during gate-electrode formation and side-wall formation. Different types of deep level traps were created in Czochralsi (CZ) and in p/p+-epitaxial wafers during side-wall formation. In comparison to the CZ wafers, a deep energy state and large hole capture cross section for the electrically active trap appears in the p/p+-epitaxial wafers. The depth profile of the deep trap in CZ wafers is shallower than that in p/p+-epitaxial wafers. This result indicates that the trap diffusivity in a CZ wafer is smaller than that in a p/p+-epitaxial wafer. Therefore, it suggests that creation of the trap in CZ wafers is influenced by the oxygen within the silicon. From results, the origin of the trap was identified to be carbon-oxygen complexes in the CZ wafer and carbon complexes in the p/p+-epitaxial wafer. Thus, the oxygen in the Si substrate plays a role in the formation of carbon-oxygen complexes and in suppressing the trap introduced into the Si substrate during SiO2 etching.
Thermal Stabilization of Non-Stoichiometric GaAs through Beryllium Doping
Authors: Lutz R.C. , Specht P. , Zhao R. , Jeong S. , Bokor J. , Weber E.R. 
Published: April 2011

AbstractBeryllium-doped, non-stoichiometric GaAs grown by MBE at low temperatures appears superior to its undoped counterpart in several key areas vital to device manufacturing. X-ray diffraction studies have indicated that material grown above 275°C shows complete thermal stability to annealing at temperatures up to 600°C. This behavior is ascribed in part to strain compensation between the small beryllium atoms and the large arsenic antisites. Consequently, outdiffusion of excess arsenic from the non-stoichiometric material into neighboring layers upon annealing or subsequent high temperature growth is expected to be negligible. Short carrier lifetime (<1 psec) and high resistivity (>104 Ω-cm) have been observed in the same as-grown material. Sub-picosecond lifetimes have been measured previously in undoped material, but the low growth temperatures required produce a supersaturation of antisites allowing for significant hopping conductivity through the defect band in as-grown material, and significant arsenic outdiffusion upon annealing. Due to electrical compensation of antisites by beryllium acceptors, materials in which the ionized antisites represent a major fraction of a relatively small total antisite concentration are now made possible by proceeding to higher growth temperatures. Thus, nonstoichiometric GaAs having a beneficial combination of thermal stability, short carrier lifetime and high resistivity can be fabricated
Damage Evolution and Mechanical Failure in Flip-chip Interconnects
Authors: Soperm A. , Wolf I. De , Pozza G. , Ignat M. , Parat G. 
Published: April 2011

ABSTRACTThe analysis of the mechanical behaviour of flip-chip interconections is an essential aspect of the reliability of the devices using this technique. When manufacturing them and during their operation, the interconective systems are submitted to thermal and mechanically induced stresses. By cyclic micromechanical testing and from analysis by micro Raman of singularities, we studied the mechanical response and the failure of samples, consisting of a substrate, the interconections and a chip.Two sort of low melting point alloys were investigated, with different metallurgies for the pads, holding the interconections.
Stress Evolution during Thermoset Cure
Authors: Mei Yuhai , Yee Albert F. , Wineman Alan S. , Xia Chaodong 
Published: April 2011

ABSTRACTThe residual stress evolution in an epoxy during isothermal curing process has been determined experimentally. It was found that for a certain curing temperature range in which the characteristic time for the molecular motions leading to volume recovery is shorter than the time scale of the experiment, an incremental elastic constitutive equation can be used to describe the mechanical response of the epoxy. It was also found that appreciable residual stresses are developed in a threedimensionally constrained epoxy resin system within the rubbery state.
Analysis of Catastrophic Field Failures Due to Conductive Anodic Filament (CAF) Formation
Authors: Ready W. J. , Smith B.A. , Turbini L.J. , Stock S.R. 
Published: April 2011

ABSTRACTUnder certain environmental conditions, printed wiring boards (PWB) respond to applied voltages by developing subsurface deposits of copper salts extending from anode to cathode along separated fiber / epoxy interfaces. The formation of these deposits, termed conductive anodic filaments (CAF) require high humidity (80%RH) and high voltage gradient (5V/mil). The humidity exposure during the storage environment may cause the failure in the use environment. CAF formation is enhanced by the use of certain hot air solder leveling (HASL) fluids and / or water soluble flux constituents.In this work, two catastrophic field failures were analyzed. Both failures were related to boards produced in a manufacturing process, which included HASL. One CAF failure occurred between a component through-hole and power plane held at a potential difference of 40V with a 0.005″ nominal spacing. The other occurred on an inner layer of a multi-layer board (MLB) between a via and ground plane held at a potential difference of 320V with 0.015” nominal spacing. The nature of the CAF was analyzed using scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). Ion chromatography (IC) was used to identify residue extracted from a failed board. The failure phenomena known as CAF poses serious longterm reliability concerns in electronic products exposed to adverse and hostile environments, especially those with closely spaced conductors.
The Study on The Under Bump Metallurgy (Ubm) and 63SN-37PB Solder Bumps Interface for Flip Chip Interconnection
Authors: Jang Se-Young , Paik Kyung-Wook 
Published: April 2011

ABSTRACTIn the flip chip interconnection on organic substrates using eutectic Pb/Sn solder bumps, highly reliable Under Bump Metallurgy (UBM) is required to maintain adhesion and solder wettability. Various UBM systems such as l.tm Al/0.2 μm Ti/5 μm Cu, l μm A1/0.2 μm Ti/l μm Cu, 1 μm A1/0.2 μm Ni/1 μm Cu and 1 μm At/10.2μm Pd/l μm Cu, laid under eutectic Pb/Sn solder of low melting point, were investigated with regard to their interfacial reactions and adhesion properties. The effects of numbers of solder reflow and aging time on the growth of intermetallic compounds (IMC) and on the solder ball shear strength were investigated. Good ball shear strength was obtained with 1 μm AI/0.2μm Ti/5μm Cu and 1 μm Al/0.2 μm Ni/l μm Cu even after 4 solder reflows or 7 day aging at 150°C. In contrast, l μm Al/0.2 μm Ti/l μm Cu and l μm A1/0.21μm Pd/μm Cu shows poor ball shear strength. The decrease of the shear strength was mainly due to the direct contact between solder and nonwettable metal such as Ti and Al resulting in a delamination. Thin 1 μm Cu and 0.2 μm Pd diffusion barrier layer were completely consumed by Cu-Sn and Pd-Sn reaction.
Readout of Magnetic Film-Based Memories by Nonlinear-Optical Magnetic Kerr Effect
Authors: Murzina T.V. , Didenko N.V. , Fedyanin A.A. , Melnikov A.V. , Misuryaev T.V. , Aktsipetrov O.A. 
Published: April 2011

AbstractMagnetic field induced second harmonic generation (MSHG) is suggested as a nonlinear-optical readout for magnetic film-based memories: Systematic studies of the nonlinear-optical magnetic Kerr effect and MSHG interferometry are carried out for (i) magnetic rare-earth iron garnet films, (ii) Gd-containing Langmuir-Blodgett films and (iii) CoxCu1-x granular films. The magneto-induced nonlinear-optical properties of thin films being used for recording the information can be easily distinguished by the MSHG nondestructive probe. An estimation of the signal-to-noise ratio (readout error) shows an acceptable value of the magnetic contrast for this potential readout.
Diluted Magnetic Semiconductor Thin Films and Multilayers
Authors: Furdyna J. K. 
Published: April 2011

AbstractWe review the properties of diluted magnetic semiconductor (DMS) thin films and multilayers, with special attention to their usefulness in magneto-optical device applications. We begin with the most widely studied DMS family, i.e., alloys of II-VI semiconductors involving Mn ions. Prospects and challenges are discussed for achieving II1-xMnxVI-based non-reciprocal devices; and for devices operating in the far infrared. We also consider the unique advantages which DMSs offer for probing the properties of semiconductor heterostructures. We then discuss ferromagnetic DMSs, including those based on the III-V semiconductor family. And we briefly review the status of hybrid ferromagnetic-semiconductor structures achieved through recent advances in epitaxy of new materials.
Magnetization Process in Cr Substituted Diluted Magnetic Semiconductor Films
Authors: Adachi N. , Hirano J. , Yamazaki T. , Okuda T. , Kitazawa H. , Kido G. 
Published: April 2011

AbstractCr substituted dilute magnetic semiconductor Cd1-xCrxSe films were grown onto fused silica and sapphire (00 · 1) substrates by vapor deposition technique. The films with wurtzite structure were obtained at composition of 0 ≤ × ≤ 0.66. Saturation magnetization and magnetic susceptibility increased as x increased. In comparison with Mn-DMS system, the initial magnetization curves saturate easily. This tendency is different from most DMS materials in which magnetic ions interact with each other antiferromagnetically. It is possible that ferromagnetic interactions exist in Cd1-xCrxSe.
Effect of Quaternary Ammonium-Modified Montmorillonites on Mechanical Properties of Polypropylene
Authors: Zhang Y. H. , Gong K. C. 
Published: April 2011

ABSTRACTHybrids of quaternary ammonium-modified montmorillonites and polypropylene were prepared by melting intercalation. Results of mechanical property measurements show that, tensile strength, modulus and impact strength of PP composites are greatly enhanced simultaneously by a small addition amount of modified montmorillonites.
High-Resolution Transmission Electron Microscope Analysis of Tungsten Carbide Thin Films
Authors: Qin Wentao , Shih W. , Lib J. , James W. , Siriwardaneane H. , Fraundorf P. 
Published: April 2011

ABSTRACTElectron diffraction patterns and high-resolution transmission electron microscope (HREM) images show that the dominant phase in tungsten carbide thin films grown by plasma enhanced chemical vapor deposition is WC(1−x). The f.c.c crystal structure and the unit cell size of WC(1−x) have been determined via electron powder diffraction. The two largest and most dominant spacings in HREM images are the {111} and {002} spacings of WC(1−x). Cross lattice fringes along the two most densely populated zones of WC(1−x) are seen. The sizes and aspect ratios of nano-crystals have been measured from HREM images. Stereo analysis of individual nano-crystals has been done. Confirmation of the 3-D structure of WC(1−x) via spacings larger than 0.15 nm will require a tilt larger than 35° between images.
Design of Novel Treated Silica Xerogels: Synthesis, Property and Reinforcement in Silicone Elastomers
Authors: Deng Q. , Bums G. T. , Hahn J. R. , Reese C. C. , Preston J. D. , Winchell S. B. 
Published: April 2011

ABSTRACTTreated silica xerogels with controlled porosity and surface area were prepared by the in-situ treatment of hydrogels with hexamethyldisiloxane in the presence of isopropyl alcohol. The resulting hydrogels were hydrophobic and readily transferred to organic solvents allowing their isolation. The surface area and porosity of the xerogel were controlled by varying the pH, time and temperature used to aggregate the hydrogel prior to treatment. The treated xerogels were evaluated as reinforcing fillers in silicone rubber formulations. When the bases were crosslinked with peroxides, silicone elastomers with acceptable mechanical properties were obtained. The relationship between the surface area, porosity and the type and degree of surface treatment of the xerogel, and its reinforcing ability was studied. In general, the mechanical properties of the elastomer increased as the filler structure increased; however, xerogels with higher surface areas were more difficult to incorporate and gave higher plasticity bases.
Preparations, Structures, and Properties of Polysiloxane-Silica Composites Prepared from a Variety of Hydrolyzable Precursors
Authors: Breiner J. M. , Mark J. E. , Beaucage G. 
Published: April 2011

ABSTRACTPoly(dimethylsiloxane) (PDMS) networks were prepared by tetrafunctionally endlinking hydroxyl-terminated chains with tetraethoxysilane (TEOS). The resulting networks were filled in-situ by hydrolysis-condensation reactions that were either acid or base catalyzed reactions on some novel precursors. These precursors included star-shaped molecules, rings, linear comb-like chains, and pre-hydrolyzed products of silanes such as TEOS. Both monomethoxy and trimethoxy groups were used as hydrolyzable groups on these molecules. The structures of the resulting composites were examined by small-angle X-ray scattering, and their mechanical properties were determined using equilibrium stress-strain measurements in elongation. Novel precursors with monomethoxy functionalities did not generate stable particulates, but those with trimethoxy functionalities did, with some improvements in mechanical properties. Partially-hydrolyzed TEOS provided the best reinforcement of these PDMS elastomers.
Effect of Pb/Ti Ratio on the Particle Size of Hydrothermal PbTiO3 Powders
Authors: Peterson C. R. , Slamovich E. B. 
Published: April 2011

ABSTRACTThe influence of Pb/Ti ratio on the particle size of hydrothermally derived lead titanate (PbTiO3) powders was investigated. Phase pure PbTiO3 powder was synthesized by reacting nanocrystalline TiC2 powder in a 1 m KOH solution for 15 h at 200°C with Pb/Ti ratios of 1 and 5. Faceted platelet particles with a low aspect ratio were formed in solutions with Pb/Ti ratios of 1 and 5. The observed particle size of PbTiO3 was 200 nm and larger when Pb/Ti = 1, while 50 - 100 nm sized particles formed when Pb/Ti = 5. In support of TEM observations, the BET specific surface area data increased from 4.4 m2/g to 7.3 m2/g as the Pb/Ti ratio was increased from I to 5. PbTiO3 particle size was controlled by either inhibiting or promoting dissolution-precipitation. Dissolution-precipitation in a high pH solution was inhibited by maintaining an excess of Pb ions in solution and it was promoted when input concentrations of Pb and Ti were equivalent.
Production Methods for Metallic Foams
Authors: Banhart J. , Baumeister J. 
Published: April 2011

ABSTRACTThe possibilities for making metallic foams or similar porous metal structures are reviewed. The various processes are classified according to the state of the starting metal - liquid, powdered, ionised. Liquid metal can be foamed directly by injecting gas, gas-releasing foaming agents or by producing supersaturated metal-gas solutions. Indirect methods include investment casting and usage of filler materials. Metal powders can also be used as starting materials for metallic foams: mixtures of such powders with foaming agents are compacted to foamable precursor materials that can be foamed in a second step. Instead of foaming agents inert gas can be directly entrapped in the precursor. Metal foams can also be made from metal powder slurries or by using polymer/powder mixtures. Finally, galvanic electro-deposition also allows to make highly porous metallic structures with open pores.
Elastic Properties of Low Density Core (LDC) Ti-6Al-4V Sandwich Cores
Authors: Queheillalt D. T. , Wadley H. N. G. , Schwartz D. S. 
Published: April 2011

ABSTRACTLightweight, structurally efficient low density core (LDC) sandwich structures can be produced by entrapping argon gas within a finely dispersed distribution of pores in a microstructure and using a high temperature anneal to cause pore growth by gas expansion. This results in a porous microstructure with a relative density as low as ∼0.70. Laser ultrasonic methods have been used to measure the longitudinal and shear wave velocities and hence the elastic properties of LDC Ti-6Al-4V cores prior to, and after gas expansion treatments of up to 48 hr at 920°C. The data was compared with several analytical models for predicting the volume fraction of porosity dependent elastic properties of porous materials.
Characterization of Porous Gasar Aluminum
Authors: Bonenberger R. J. , Kee A. J. , Everett R. K. , Matic P. 
Published: April 2011

ABSTRACTExperimental and numerical analyses were performed on porous aluminum samples to evaluate microstructure and mechanical properties. Experiments consisted of tensile tests on dog-bone specimens containing 9 to 17% porosity, which were instrumented with axial and transverse extensometers. Properties measured included Young's modulus, Poisson's ratio, proportional limit, 0.2% offset yield strength, and ultimate tensile strength. Results indicated that Young's modulus and all strengths decreased with increasing porosity, but Poisson's ratio remained constant with porosity. For the numerical simulations, 3-D, mesoscale, multilayer models were constructed to evaluate the effects of pore morphology and interactions on material properties. The models allowed systematic spatial positioning of the pore within the cell and the ability to form solid zones. Pore arrangement, the effect of constraint, and gradients on the stress state were investigated. By using different combinations of hex cells as building blocks, several complicated microstructural arrangements were simulated.
Compressive, Tensile and Shear Testing of Melt-Foamed Aluminium
Authors: Von Hagen H. , Bleck W. 
Published: April 2011

ABSTRACTFor construction purposes it is utterly important to get detailed information on the possible influence of the foam thickness on the mechanical properties and on the deformation behaviour of metallic foams. The effect of compressive, tensile and shear loads on aluminium foam samples has been examined with the testing methods for sandwich material as described in German and ASTM-standards. The aim is to provide more data on these mechanical properties varying the sample density and thickness. Regarding the results the most reliable material parameters as well as steps towards a relationship between the different strength parameters can be obtained.
Effects of Thermomechanical Processing on the Resulting Mechanical Properties of 6101 Aluminum Foam
Authors: Margevicius R. W. , Stanek P. W. , Jacobson L. A. 
Published: April 2011

ABSTRACTHigh porosity aluminum was fabricated in a number of ways. The starting material was a cast 6101 aluminum that had a relative density of 9.8%. The cast aluminum block was compressed by uniaxial, biaxial, and triaxial densification. Uniaxial compression was done at room temperature and 200°C. Biaxial compression was achieved by unidirectional rolling at room temperature and 200°C. Triaxial compression was done by cold isostatic pressing at 3.4, 6.7, and 34 MPa (0.5, 1.0, and 5.0 ksi). Metallography and mechanical test specimens were machined from the processed bars. The mechanical properties showed that the relative yield strength depended both on relative density and processing temperature.
Laser Ultrasonic Instrumentation for Accurate Temperature Measurement of Silicon Wafers in Rapid Thermal Processing Systems
Authors: Klimek Dan , Anthonyt Brian , Abbate Agostino , Kotidis Petros 
Published: April 2011

ABSTRACTResults are presented that demonstrate the use of laser ultrasonic methods to determine the temperature of silicon wafers under conditions consistent with applications in the RTP industry. The results show that it is possible to measure the temperature of Si(100) wafers to an accuracy approaching ± 1°C (1σ) even with wafer thickness variation over a range of 2 to 3 percent.
Cathodoluminescence Studies of Si-Sio2 Interfaces Prepared by Plasma-Assisted Oxidation and Subjected to Post-Oxidation Rapid Thermal Annealing
Authors: Schafer J. , Young A. P. , Brillson L. J. , Niimi H. , Lucovsky G. 
Published: April 2011

ABSTRACTWe have used low energy cathodolumrdinescence spectroscopy (CLS) to characterize defects at ultrathin (50 Å) silicon dioxide films, prepared on Si substrates by low-temperature plasma deposition. Variable-depth excitation with different electron injection energies provided a clear distinction between deep levels localized within the films versus at their interfaces. Defect bands are evident at 0.8 eV and 1.9 eV, characteristic of an amorphous, silicon-rich local bonding environment. Closer to the film surface, CLS reveals a defect at 2.7 eV indicative of oxygen vacancies in stoichiometric SiO2. The effect of hydrogenation at 400°C, rapid thermal annealing at 900°C, and especially the combination of both processing steps is shown to reduce the density of these defects dramatically.