bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cyclic Deformation Behavior of Ni3Ge Single Crystals At Room Temperature
Authors: Pak Han-Ryong , Hsiung Leih-Ming , Kato Masaharu 
Published: March 2011

ABSTRACTFully reversed strain-controlled, tension-compression tests were performed at room temperature to study cyclic-deformation properties of Ni3Ge single crystals. The cyclic deformation is performed with the stress axis parallel to the [1 1.94 2.69] direction at a strain rate of 1.0 × 10-4 s-1 and at a total-strain amplitude between 5.0 × 10-4 and 1.5 × 10-3. Cyclic strain-hardening occurs to saturation over the range of the employed strain amplitudes. The cyclic-stress amplitude is higher in compression than in tension at a plastic-strain amplitude larger than 1 × 10-5 where screw dislocations are operative. This stress asymmetry becomes more prominent (i.e., the mean stress-amplitude becomes larger in magnitude) as the plastic-strain amplitude becomes larger. At a plastic-strain amplitude less than 1 × 10-5 where edge dislocations are operative, the stress amplitude is symmetric. A similar stress asymmetry is also observed for monotonic flow stress. The cyclic hardening is explained by considering an interaction between the screw dislocations.
Effects of Do3 Transitions on the Yield Behavior of Fe-Al Alloys
Authors: Inouye H. 
Published: March 2011

ABSTRACTThe effect of DO3 transitions on the yield behavior of alloys near the Fe3 Al composition was investigated by tensile tests. Above 400°C, DO3 (Fe3 Al) ordered alloys exhibited an anomalous increase in yield strength with temperature with a peak value around 560 to 600°C which was not observed if the DO3 ordered alloys were also aged before testing. This yield behavior is explained by the precipitation of a (disordered solid solution) and the formation of B2 (FeAl) via the sequential reactions: DO3→α+DO3→α+B2.
Creep in Ordered Nickel Base Alloys
Authors: Strutt P. R. , Kear B. H. 
Published: March 2011

ABSTRACTThis paper examines the fundamentals of deformation behavior in ordered y′ (Ni3Al), β (NiAl) and β′ (Ni2AITi) phases, and specific two phase y/y′ and B/B′ alloys. The relative creep strengths of these ordered nickel-base alloys are discussed. Differences in creep behavior are explained in terms of the effects of temperature, crystallographic orientation and alloying on creep deformation mode. In particular, it is shown that trace additions of boron and carbon to y/y′ alloys, or deviations from stoichiometry in β′ -type alloys can exert a strong influence on creep behavior.
The Production and Thermal Stability of a Refined Dispersion of Er2O3 in Ti3Al using Rapid Solidification Processing
Authors: Konitzer D. G. , Fraser H. L. 
Published: March 2011

ABSTRACTThe use of rapid solidification processing to produce a refined dispersion of second phase in Ti3Al is demonstrated. Laser surface melting produces a disordered solid solution of Ti and Al with a supersaturation of Er and 0. A refined dispersion of Er2O3 is formed on heat treatment at 973 K. This oxide is found to be stable at elevated temperatures up to 1173 K.
Volume and Grain Boundary Diffusion in Ll2Alloys with Special Reference to Ni3Al Compounds
Authors: Chou T. C. , Chou Y. T. 
Published: March 2011

ABSTRACTExperiment and theory of diffusion in Ll(2) alloys are briefly reviewed. Current work on volume and grain boundary diffusion in Ni(3)Al alloys are presented and discussed.
Physical Properties of Ni3Al Containing 24 and 25 Atomic Percent Aluminum
Authors: Williams R. K. , Graves R. S. , Weaver F. J. , McElroy D. L. 
Published: March 2011

ABSTRACTThermal conductivity, electrical resistivity, Seebeck coefficient and thermal expansion data were obtained on well-annealed Ni3Al containing 24 and 25 at. % Al. The results span the temperature range 300 to 1000 K. The expansion coefficients did not vary with composition and increased with temperature, reaching values of aIout 17 × 10−6 K−1 at 1000 K. The thermal conductivity and electrical resistivity changed rapidly with composition, and the thermal conductivity of 24 at. % Al is as much as 30% lower than that for stoichiometric Ni3A1. The electronic Lorenz function of Ni3Al was obtained by subtracting the estimated phonon conductivity component and found to be within about 5% of the Sommerfeld prediction from 300 to 1000 K. The electrical resistivity results for stoichiometric Ni 3Al are influenced by the loss of ferromagnetic order at lower temperatures and are not adequately described by the Bloch-Grüneisen equation.
Pseudoelasticity and Pseudotwinning in Ordered Shape-Memory Alloys
Authors: Zangwill A. , Bruinsma R. 
Published: March 2011

ABSTRACTShape-memory behavior is a complicated phenomenon which Intimately relates macroscopic strain recovery with martensitic phase transformation. A vital step In the theoretical understanding of this effect is a clear picture of a superficially rather simpler phenomenon: martensitic pseudoelasticity. Within the martensftic phase, a number of ordered alloys exhibit deformation strain recovery which Is reminiscent of rubber elasticity. The deformation Is observed to occur via coherent motion of parallel twin boundaries. In this case, where long range elastic accomodatlon forces play no role, the origin of the restoring force on the twin boundaries is still unclear. In this work, we present a quantitative theory which generalizes previous suggestions in the literature and unifies this phenomenon with elastic mechanical untwinning. Our description is based on the concept of a “pseudotwin” originally proposed by Laves and later elucidated by Cahn. Here, the motion of a twin boundary generates a new metastable crystallographic structure (the pseudo-twin) of locally higher free energy. This notion not only provides a source for a “volume” restoring force but leads to a natural descriptioni of observed stabilization effects. Specific experiments to test our description will be proposed.
Kinetics of the SRO-LRO Transformation in NI4MO
Authors: Stansbury E. E. 
Published: March 2011

ABSTRACTThe isothermal time-temperature dependence of the transformation from SRO to LRO as measured by resistivity changes is given. Problems of defining an initial state from which the transformation occurs are reviewed with emphasis on the microdomain structure from which the LRO structure develops. Questions of homogeneous transformation relative to heterogeneous transformation by clear nucleation and growth are addressed in terms of experimental evidence and theoretical predictions. Strong evidence for a nucleation and growth mechanism, at least above 750° C, is presented.
Study of the Crystalline to Amorphous Silicon Boundary Following Laser Induced Solid Phase Epitaxy.
Authors: Gonchond J. P. , Rozgonyi G. A. , Bois D. 
Published: March 2011

ABSTRACTEBIC and voltage contrast SEM microscopy, combined with optical microscopy. chemical etching and Talystep profiling have been used to investigate cw laser annealing of a-Si in the slip-free SPE regime. Special attention is devoted to the edges and extremities of the line scans, i.e. to the c-to a-Si boundary. At very low power, evidence is given for an initial reordering and thus electrical activation stage of the a-Si. For the higher power range regrowth occurs through two different processes. The EBIC yield is interpreted in terms of a balance between annealing of the ion implantation damage and defect generation in the si substrate during the laser annealing. These results are extended to the case of a scanned electron beam annealing.
Evidence Against a Reduced Melting Temperature in Amorphous Silicon
Authors: Kokorowski S.A. , Olson G.L. , Roth J.A. , Hess L.D. 
Published: March 2011

ABSTRACTExperimental results are presented which indicate that amorphous silicon does not melt at a temperature significantly lower than the melting point of crystalline silicon (1693°K), contrary to recent reports which suggest a 300 to 500°K melting point depression. Time-resolved optical reflectivity measurements are used to determine the temperature and to investigate phase changes which occur in silicon during cw laser heating. It is shown that amorphous silicon films produced by arsenic implantation into Si(100) do not melt when heated to temperatures in excess of 1600°K. An alternate interpretation of previous work that is consistent with the present findings is proposed.
Laser Processing in Silicon Molecular Beam Epitaxy
Authors: De Jong T. , Smit L. , Korablev V.V. , Saris F.W. 
Published: March 2011

ABSTRACTWe have grown epitaxial silicon films on silicon (100), (110) and (111) oriented substrates, using pulsed ruby laser irradiation as a means to obtain clean, ordered substrate surfaces. On these surfaces epitaxial layers were grown in two ways: I. Rȯom temperature deposition and pulsed laser induced epitaxy of 100–300 nm films was carried out repeatedly, yielding ∼1 μm thick epitaxial layers. II. Low temperature molecular beam epitaxy (M.B.E.), even at 250°C on Si(100),of layers up to 1 μm.Applying the second technique to implanted substrates, we annealed and cleaned arsenic implanted silicon (100) samples in situ, and produced epitaxial overlayers of 100–1000 nm, thus creating a buried n-type channel in silicon.
Oxygen-Trapping and Oxidation Induced by Laser Irradiation in Silicon
Authors: Liu Yung S. , Chiang Shin-Wu , Katz W. 
Published: March 2011

ABSTRACTRapid oxidation in silicon induced by nanosecond UV laser pulses has been recently reported [1]. A significant amount of oxygen was observed to be incorporated in theregrown silicon layer when irradiation took place in air or in oxygen ambient. The fundamental interaction and transport kinetics involved include: incorporation of impurity during surface melting, trapping of solute during resolidification, and rapid reaction to form chemical bonds. The present study has investigated the mechanism of oxygen incorporation and trapping under various regrowth conditions. Oxygen depth-concentration distributions were analyzed using secondary-ion-mass spectroscopy (SIMS). The oxide formed was studied using differential Fourier-Transformed IR (FT-IR) spectroscopy.
Surface Electronic Properties of Ionimplanted Laser-Annealed Si(111)
Authors: Eastman D.E. , Heimann P. , Himpsel F.J. , Reihl B. , Zehner D.M. , White C.W. 
Published: March 2011

ABSTRACTHighly-degenerate As-doped n-type and B-doped p-type Si(l11)−(1×1) surfaces have been prepared via ion implantation and laser annealing and studied using photoemission. For As concentrations of ∼4–7%, surface states become very different from those for intrinsic Si(l11)−(1×1) and the Fermi level EF at the surface moves to the conduction band minima resulting in a zero height n-type Schottky barrier. Emission from the conduction band minima has been directly viewed in momentum space.
Laser Induced Diffusion of Radioactive As into Si
Authors: Pfeiffer Loren , Kovacs T. , Celler G. K. , Trimble L. E. , Jacobson D. C. 
Published: March 2011

ABSTRACTA high efficiency technique for incorporating As or other high volatility elements into Si and other semiconductors by laser pulse processing is described. By this method more than 80% of the As atoms painted onto a Si surface were made to relocate onto substitutional sites in the 73Si crystal. Mossbauer analysis of laser diffused As atoms in a Ge crystal indicates that although the final As sites are >97% substitutional, the majority are associated with one or more defects not seen in conventionally diffused material.
Pulse Electron Beam Annealing of Phosphorus-Implanted Silicon
Authors: Borisenko Victor , Labunov Vladimir 
Published: March 2011

ABSTRACTLow-energy electron beam pulses of 0.2–0.8 s duration have been used to anneal silicon wafers implanted with 1.4×1015 P+/cm2 at 30 and 100 keV. Sheet resistivity, carrier concentration profiles and phosphorus atom distributions have been measured. It has been found that the impurity is completely activated without a noticeable diffusion at the energy density of 30 J/cm2 and higher. The annealing process appears to take place via a solid phase diffusion and annihilation of radiation defects.
CW Laser Induced Deep Level Defects in Virgin Silicon.
Authors: Chantre A. , Kechouane M. , Bois D. 
Published: March 2011

ABSTRACTDeep Level Transient Spectroscopy has been used to investigate cw laser induced defects in virgin silicon. Two main regimes have been found. In the solid phase regime, two well defined deep levels at Ec−0.19 eV and Ec−0.45 eV are observed. This point defect introduction is proposed to be involved in the degradation of ion-implanted cw laser annealed junctions. The mechanism leading to point defects generation is likely to involve trapping of in–diffused vacancies, quenched–in from the high temperature state. In the slip lines or melt regimes, additionnal deep levels are detected, which are ascribed to dislocations.
Defect Analysis of Silicon Irradiated by Pulsed Ion Beams
Authors: Mader Siegfried , Chu Wei-Kan 
Published: March 2011

ABSTRACTSilicon wafers with (001), (011), and (111) orientations were irradiated with pulsed Ba beams that caused shallow surface melting. Upon resolidification the dislocations are trapped with configurations which are characteristically different for each orientation. A novel feature are dislocations with a [100] Burgers vectors. The dislocations accommodate part of the thermal misfit between substrate and solidifying layer.
Interplay of Soret vs. Normal Impurity Diffusion During Laser or E-Beam Induced Heat Flow Transients in Metals
Authors: Dona' Dalle Rose L.F. , Miotello A. 
Published: March 2011

ABSTRACTIn the growing amount of the experimental data on the diffu sion processes of implanted impurities in a metal sample irradiated by highly energetic and very short pulses, some order may be introduced by the knowledge of the structure of induced thermal transient. The differences in such a structure due to two different energy sources (laser and electron beam) are de scribed with reference to the conditions under which Soret diffusion may be experimentally observed as distinct from nor mal diffusion. Laser induced transient seem to offer this possibility.Some previously reported diffusion processes in laser irra diated systems are reinterpreted on this basis, showing the importance of the Soret effect.
Raman and Optical Properties of the Pulsed Laser Annealing Phase of SI
Authors: Compaan A. , Aydinli A. , Lee M. C. , LO H. W. 
Published: March 2011

ABSTRACTRaman measurements of temperature reported earlier have been repeated using a doubled Nd: YAG pulse for excitation and an electronically delayed dye laser pulse. These results, together with a variety of experimental tests of the Raman method, confirm the validity of the small temperature rise during pulsed laser annealing. Transmission measurements spanning the visible and near IR show that there exists a thin (∼ 70 nm) layer at the surface in which the induced absorption coefficient is ∼ 7 × 105 cm−1.
Seeded Growth of Si Over SiO2 Substrates by CW Laser Irradiation
Authors: Trimble L. E. , Celler G. K. , Ng K. K. , Baumgart H. , Leamy H. J. 
Published: March 2011

ABSTRACTSeeded epitaxial growth of Si over SiO2 is demonstrated in two types of structures. In the first case, rectangular pads of deposited Si were recessed into a thick SiO2 film. Narrow (≃ 5μm) via holes in SiO2 linked the pads with the bulk Si substrates. In the second embodiment, SiO2 patterns were recessed into the Si wafers which were then covered with a continuous 0.5μm poly-Si layer. In both cases, nearly planar geometries were maintained by use of local oxidation and etching techniques. Silicon was recrystallized with a focused Ar+ laser beam. Depending on the scanning conditions and the Si pattern geometry, single crystal growth propagated between 30 and >500μm. The factors influencing the extent and quality of the crystallized regions are discussed.
Line-Source E-Beam Crystallization of SI on Silicon Nitride Layers
Authors: Knapp J. A. , Picraux S. T. , Lee K. , Gibbons J. F. , Sedgwick T. O , Depp S. W. 
Published: March 2011

ABSTRACTWe report the use of a swept line–source electron beam for liquid phase recrystallization of Si films on Si3N4 layers over Si substrates. For the case of 5000Å of Si on 1000Å of Si3N4 layers over Si Si3N4, we have demonstrated the growth of Si crystalline regions as large as 0.5 × 5 mm of predominately [100] orientation normal to the film and [010] in the sweep direction. The nucleation of grain growth for this case occurred at small defects in the nitride layer at the edge of the treated area, growing out as far as 500 μm over intact nitride. Thicker nitrides (2500Å) remained intact at power densities useful for treating the Si film. For this thicker nitride we demonstrate non–seeded growth for single and repetitively melted Si. In all cases the surface morphology of the regrown regions is suggestive of rapid growth along <100> directions.
Characterization of Thermal Oxides of Laser Annealed Polysilicon
Authors: Shah Rajiv R. , Mays Robert , Lloyd Crosthwait D. 
Published: March 2011

ABSTRACTWe report an investigation of the effects of laser processing on the thermal oxides of polysilicon. LPCVD polysilicon, 500 nm thick, deposited on 500 nm thermal oxide of single crystal silicon was laser processed at various stages in the process sequence for device fabrication. Effects of CW Ar+ and pulsed 1.06 and 0.53 μm laser processing were investigated. Laser annealed polysilicon was oxidized in a steam ambient. Using a second level of polysilicon, guard ring diode and capacitors were fabricated. Electrical characterization revealed an improvement in breakdown field strengths of these oxides without deleterious effects on any of the associated interfaces.
Laser Processing of Porous Silicon
Authors: Baumgart H. , Frye R. C. , Trimble L. E. , Leamy H. J. , Celler G. K. 
Published: March 2011

ABSTRACTSilicon can be prepared in a unique morphological form by anodic dissolution in HF. The resultant material contains pores of 10–100Å diameter in numbers sufficient toproduce a high surface area, low density single crystal. We have investigated the potential of both pulsed and CW laser processing in this material for dielectric isolation applications. Pulsed processing at λ = 532 nm yields fused surface layer structures that are epitaxial. The porous Si that underlies this surface film is undisturbed and can beoxidized to produce vertical isolation from the substrate.
Schottky-Diodes in Laser Recrystallized Polysilicon
Authors: Schaber H. , Schelpmeier H. , Werner W.M. , Cutter D. 
Published: March 2011

ABSTRACTSchottky-diodes on laser recrystallized polycrystalline silicon are studied and compared to diodes fabricated on conventional, fine grained poly-Si. A strong dependence of reverse current on grain size is found and can be quantitatively explained by carrier generation at grain boundaries. In order to reduce the series resistance of the diodes, various methods to create a n+n doping profile in the recrystallized layer are investigated.
Non Alloyed Ohmic Contacts for GaAs Coplanar Mixer Diodes
Authors: Woodcock John M. 
Published: March 2011

ABSTRACTA Q-switched ruby laser has been used to anneal gallium arsenide which has either been implanted with a donor or coated with a thin layer of material containing the donor. Silicon nitride (∼500Å), germanium (∼50Å), tin (∼50Å) and silicon (∼500Å) have been used and in all cases laser annealing produces n-type doping levels in excess of 1019cm−3. Non alloyed ohmic contacts have been made on these heavily doped layers with specific contact resistances as low as 1.4 × 10−6Ω cm2. These contacts have been used in the fabrication of fine geometry coplanar mixer diodes. Ideality factors of 1.1 have been measured from the d.c. current voltage characteristics and diodes with a total capacitance of O.03pF have series resistances below 10 ohms. Matched pairs of these devices have given a 4.8dB conversion loss at 35GHz in a fin line balanced mixer.
Compositional Analysis and Electrical Property Measurements of CW Laser-Annealed InSb
Authors: Liu Yung S. , Wei C.Y. , Tantraporn W. , Chiang S.W. , Possin G.E. 
Published: March 2011

ABSTRACTCharacteristics of CW Ar-ion laser annealed InSb has been studied; properties include stoichiometric composition analysis and electrical C-V measurements. The stoichiometry compositions of laser-annealed samples at different power levels and scan speeds have been studied using an electron microprobe technique. Results were compared with electrical C-V measurements using MOS structures.
Surface Temperatures Produced In Silicon Using Large Diameter Scanning Cw Sources
Authors: Gibbons J. F. , Christel L. A. , Lietoila A. 
Published: March 2011

ABSTRACTThe temperature induced at the surface of a silicon wafer is calculated for both circular and rectangular scanning beams, assuming both a thermally isolated and heat sunk back surface. In the former case, the problem is one of simple uniform heating with radiative cooling at slow scan speeds. A significant thermal gradient is produced across the wafer at high scan speeds. In the latter case, a one-dimensional analysis suffices except for beam diameters less than about twice the wafer thickness, when lateral heat diffusion effects are present.
Electron Energy Distributions During Pulsed Laser Annealing and Damage of Silicon
Authors: Williams R. T. , Kabler M. N. , Long J. P. , Rife J. C. , Royt T. R. 
Published: March 2011

ABSTRACTSpectra of photoelectrons and thermionic electrons emitted from silicon during pulsed laser irradiation at energy densities encompassing the thresholds for laser annealing and damage are reported. Annealing is accomplished with a 90-nsec pulse of 532-nm light, which may be accompanied by a 266-nm probe pulse. A cylindrical mirror analyzer is used for energy resolution of emitted electrons. Time-resolved reflectivity at 633 nm verifies attainment of the high-reflectivity annealing phase. Spectral widths and total yields imply a modest electron temperature (T < 3000 K) during annealing. The data suggest that the work function of the silicon (111) face may increase about 0.6 eV upon transition to the molten phase.
Ductile Tantalum Oxide Protective Coatings
Authors: Rizkalla Hani L. , Wellinghoff Stephen T. 
Published: March 2011

AbstractAmorphous, anodic Ta2O5 films of 400 A thickness deposited on deformable polymer substrates deformed by microshear banding even at 5–10% tensile strain. Electron beam evaporated Ta2O5 (EBE) were considerably more brittle in tension on the same substrates, fracturing at strains less than 1%. Even though both films were amorphous to electron diffraction the EBE vibrational spectrum in the Ta2O5 region (900 cm-1 - 400 cm-1) was more reminiscent of thermally oxidized material that appears to have greater microstructural order. A significant dynamic mechanical peak was observed at 60–90°C for both Al and Ta foils coated with either anodic or EBE Ta2O5 films. This process was assigned to relaxation of interfacial stresses induced by atomic motion in the oxide in this temperature range. In the face of the rather similar dynamic mechanical spectra we suspect that the presence of a greater Packing heterogeneity might explain the greater brittleness of the EBE films.
Contact Angle Measurements of Wetting In Pristine and Ion Implanted High Modulus Benzene Derived Graphite Fibers
Authors: de Hodgins O. C. , Dresselhaus M. S. , Uhlmann D. 
Published: March 2011

AbstractMeasurements are reported of the contact angles of benzene-derived carbon fibers with de-ionized water, aminopropyltriethoxy silane and du Pont 5878 polyimide solutions. Both pristine fibers and fibers implanted with 5×1012 cm-2 and 1×1015 cm-2 fluences of 31p ions were investigated. Such implantation was observed to decrease the contact angle in all three solutions. The ion implantation had no significant effect on tensile strength, but did result in increased structural disorder (as reflected in the width of the main wide angle X-ray diffraction peak) and increased surface roughness. The increased disorder and roughness are believed to be principally responsible for the observed change in wetting angle.