bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimations Of Changes in Microcrack-Population, Elastic Modulus, and Permeability, Due to Differential-Thermal Expansion in Plutonic Rock Surrounding A Nuclear Fuel Waste Disposal Vault
Authors: Wilkins B. J. , Liner Y. , Rigby G. L. 
Published: March 2011

AbstractAtomic Energy of Canada Limited is studying the disposal of nuclear fuel-waste in a vault in plutonic rock. An important part of this study is to develop models to assess the rate of escape of waste components to the biosphere. In these models time-dependent changes in the system are important. One such change is the increase in temperature of the rock mass immediately surrounding the vault, and in the far-field. Differential- thermal expansion between rock constituents (crystals), and the expansion of trapped water, will produce microcracking and, hence, possibly changes in intact-rock elastic modulus and permeability. This paper describes the model devised to estimate the extent of microcracking in rock surrounding a vault, and the anticipated changes in rock elastic modulus and permeability. The model is applied to a possible vault, located at various depths in plutonic rock typical of the Canadian Shield. It estimates the dimensions of an envelope outside of which the influence of the vault on microcracking will be negligible.
Characteristics of Laser/Energy Beam-Melted Silicon Mechanical Damages
Authors: Lee El-Hang 
Published: March 2011

ABSTRACTWe describe what appears to be a first attempt to melt and recrystallize macroscopic (10-20 μm deep) silicon mechanical damage that is induced from wafer modification such as slicing and lapping. Recrystallized surfaces appear mirror shiny, with significantly improved surface smoothness, as compared to the coarse texture of damaged surfaces. The crystallinity also appears good in general. Through the depth of melt were observed indications of impurity migration, probably caused by accumulated segregation at the advancing solid-liquid interface. Recrystallized surfaces, despite their smoothness, remain topologically uneven as a result of lateral mass transport. In addition, the extensive heat required to melt thick layers of silicon causes slip dislocations.
Time-Resolved Picosecond Optical Study of Laser-Excited Graphite
Authors: Huang C. Y. , Malvezzi A. M. , Liu J. N. , Bloembergen N. 
Published: March 2011

ABSTRACTThe pump-and-probe technique is employed to perform picosecond timeresolved measurements of the reflectivity changes in highly oriented pyrolitic graphite excited by 0.532-μm pump pulses. At low pump fluences, the presence of a short-lived plasma and a high-temperature gradient gives rise to an increase in the reflectivity probed at 1.9 μm but causes a decrease at 1.064 μm. At the threshold fluence, 140 mJ/cm2, the reflectivity drops abruptly, marking a phase transformation. Above the threshold, the reflectivity drops to -0.2 from its original value of 0.42 at 1.064 μm and to -0.4 from its ambient value of 0.50 at 1.9 μm. This new phase persists only for a few nanoseconds.
Transient Conductance Measurements And Heat-Flow Analysis of Pulsed-Laser-Induced Melting of Aluminum Thin Films
Authors: Tsao J. Y. , Picraux S. T. , Peercy P. S. , Thompson Michael O. 
Published: March 2011

ABSTRACTWe report time-resolved electrical-resistance measurements during pulsed-laser melting of a metal, aluminum. The resistances are correlated with the thresholds for partial and full melting. We describe a semianalytic solution, based on an impulse-response function, for the response, to a heating pulse, of a thin film of good thermal conductor supported by an infinite substrate. The results agree well with the resistance measurements, and confirm our interpretation of the data. In addition, time-resolved reflectance measurements establish that, in this geometry, melting and solidification proceed via the motion of a well-defined, planar liquid/solid interface, whose position can be deduced from the resistance measurements. These measurements permit the first real-time determinations of melt-depths and quenching histories during rapid-solidification processing of metals.
The Crystalline-To-Amorphous Phase Transition In Irradiated Silicon
Authors: Seidman D.N. , Averback R.S. , Okamoto P.R. , Baily A.C. 
Published: March 2011

ABSTRACTThe amorphous(a)-to-crystalline (c) phase transition has been studied in electron(e-) and/or ion irradiated silicon (Si). The irradiations were performed in i n the Argonne High Voltage Microscope-Tandem Facility The irradia ion of Si, at <10 K, with 1-MeV e- to a fluence of 14 dpa failed to induce the c-to-a transition. Whereas an irradiation, at <10 K, with 1.0 or 1.5-MeV Kr+ ions induced the c-to-a transition by a fluence of ≈0.37 dpa. Alternatively a dual irradiation, at 10 K, with 1.0-MeV e and 1.0 or 1.5-MeV Kr+ to a Kr+ fluence of 1.5 dpa -- where the ratio of the displacement rates for e- to ions was ≈0.5--resulted in the Si specimen retaining a degree of crystallinity. These results are discussed in terms of the degree of dispersion of point defects in the primary state of radiation damage and the mobilities of point defects.
Ion Beam Deposition of Materials At 40–200 Ev: Effect of Ion Energy And Substrate Temperature On Interface, Thin Film And Damage Formation
Authors: Herbots N. , Appleton B.R. , Pennycook S.J. , Noggle T.S. , Zuhr R.A. 
Published: March 2011

ABSTRACTIon beam deposition (IBD), the process whereby magnetically analyzed ions are directly deposited on single crystal substrates, has been studied for 74Ge and 30Si ions on Si(100) and Ge(100). The effects of sputtercleaning prior to deposition and substrate temperature during deposition were investigated. Three analytical techniques were systematically used to obtain information on the deposited films: (1) Rutherford backscattering combined with ion channeling, (2) cross-section TEM, and (3) Seeman-Bohlin X-ray diffraction. In the energy range explored (40–200 eV), the width of the interface between the IBD film and the substrate was found to be always less than 1 nm. Each IBD layer was highly uniform in thickness and composition for deposition temperatures from 300 K to 900 K. Without prior sputter-cleaning and annealing of the Si(100) and Ge(100) substrates, no epitaxy was observed. UHV conditions were found to be a requirement in order to grow crystalline Si films presenting bulk-like density. This was not the case for Ge films which showed bulk-like density for IBD at higher pressures. Results on the first Si/Ge superstructure grown by IBD are also shown.
Ion Irradiation Induced Amorphous To Quasicrystalline Transformation: Composition Dependence In The Almn System
Authors: Lilienfeld D. A. , Nastasi M. , Johnson H. H. , Ast D. G. , Mayer J. W. 
Published: March 2011

ABSTRACTMultilayered Al84Mn16 films ion irradiated with Xe at room temperature transform into an amorphous phase. Subsequent Xe ion irradiation at 150C transforms the amorphous to the quasicrystalline phase. The quasicrystalline structure may be formed in the composition range of 91 atomic % Al to 80 atomic % Al.
Pulsed Laser And Ion Beam Surface Modification of Sintered, Alpha-Sic
Authors: More K. L. , Davis R. F. , Appleton B. R. , Lowndes D. , Smith P. 
Published: March 2011

ABSTRACTPulsed laser annealing and ion beam mixing have been used as surface modification techniques to enhance the physical properties of polycrystalline α-SiC. Thin Ni overlayers (20 nm - 100 nm) were evaporated onto the SiC surface. The specimens were subsequently irradiated with pulses of a ruby or krypton fluoride (KrF) excimer laser or bombarded with high energy Xe+ or Si+ ions. Both processes are non-equilibrium methods and each has been shown to induce unique microstructural changes at the SiC surface which are not attainable by conventional thermal treatments. Under particular (and optimum) processing conditions, these changes considerably increased the mechanical properties of the SiC; following laser irradiation, the fracture strength of the SiC was increased by as much as 50%, but after ion beam mixing, no strength increase was observed.High resolution cross-section transmission electron microscopy (X-TEM), scanning electron microscopy (SEM), and Rutherford backscattering techniques were used to characterize the extent of mixing between the Ni and the SiC as a result of the surface modification.
Some Characteristics of Al12Mo in Aluminum Annealed After Implantation with Molybdenum
Authors: Stephenson L. D. , Bentley J. , Benson R. B. , Hubler G. K. , Parrish P. A. 
Published: March 2011

ABSTRACTThe characteristics of A112Mo formed in aluminum annealed after implantation with selected maximum molybdenum concentrations were examined by analytical electron microscopy techniques. The A112MO was isolated as the only precipitate in the microstructure for maximum as-implanted molybdenum concentrations up to 11 atomic percent. The morphology of the A112MO can be selected by choosing the maximum as-implanted molybdenum level over the same concentration range. A predominantly lamellar A112MO precipitate structure formed when aluminum was annealed at 550°C after implantation with maximum molybdenum concentrations in the range of 3.3 - 4.4 at.%. The orientation of the body centered cubic (bcc) A112Mo precipitate with respect to the face centered cubic (fcc) matrix can be expressed as (123)p || (002)m and [301]p || [310]m. An explanation for the experimentally observed orientation relationship was developed based on the characteristic relationships between the bcc A112MO precipitate and the fcc matrix. A continuous film of A112MO formed in the surface modified region when aluminum was annealed after implantation with maximum molybdenum concentrations in the approximate range of 8-11 at.%. The microstructure of the A112Mo film was found to depend on the annealing temperature. A granular film formed after annealing at 550°C whereas a mottled film formed after annealing at 400°C. Sequential annealing experiments revealed that the mottled film transforms to a granular film which indicates the mottled film is metastable.
Role of Chemical Disordering In Eleci3O Irradiation Induced Amorphisation
Authors: Luzzi D.E. , Mori H. , Fujita H. , Meshii M. 
Published: March 2011

ABSTRACTThe electron irradiation induced crystalline to amorphous (C-A) transition was investigated in the Cu-Ti alloy system. As the transition is found to be dose dependent, the energy accumulated during the irradiation must make the crystal lattice unstable with respect to the amorphous state. In this paper, two possibilities for this energy accumulation, chemical disordering and the accumulation of point defects, is examined using the intermetallic compound CuTi2. Also, the effect of deviations from stoichiometry on the C-A transition is investigated in the compound CuTi. The Bragg-Williams long-rang order parameter, S, was found to decrease with electron dose. The rate of this decrease decreased with increasing temperature. At a critical temperature, the maximum obtainable degree of chemical disordering critically decreased. This critical temperature coincided with the critical temperature for the C-A transition, favoring the chemical disordering as the primary driving force. In CuTi, the C-A transition was hindered when there existed a Cu-rich deviation from stoichiometry.
A Comparative Study of The Crystallization of Ni-P Amorphous Alloys Produced By Ion-Implantation And Melt Spinning.
Authors: Hamlyn-Harris James , John D. H. St. , Sood D. K. 
Published: March 2011

ABSTRACTImplantation of 4OkeV P+ ions into high purity Ni was employed at room temperature to a dose of 3×10E17 ions/cm2 to produce an 1100 A thick amorphous surface alloy of Ni-14 wt% P. Commercially available melt spun metallic glass ribbons of nominal composition, Ni-il wt% P were used for comparison of crystallization behaviour studied with TEM and RBS techniques. The DTA analysis was employed to construct a TTT curve for the melt spun glass, which was then used as a guide for selecting time and temperature of crystallization of the implanted amorphous alloy. The melt implanted glass is found to be less stable and crystallizes more readily than melt spun glass of similar composition. A detailed study on nucleation and growth of crystallites, mode of crystallization and effect of surface proximity will be presented.
Transition Between Condensed Phases In Si And Ge
Authors: Turnbull David 
Published: March 2011

ABSTRACTThe thermodynamic interrelation between the amorphous semiconducting (a-sc), the diamond cubic (c-sc) and the liquid metal (lm) states of Ge and Si is reviewed with especial emphasis on the question of the thermodynamic uniqueness of the a-sc state following its structural relaxation. The experience on the occurrence of the direct lm→a-sc transition and its reverse is surveyed and interpreted. This experience, in conjunction with the lm undercooling studies of Devaud and the author, indicates that the formation, in the metastable regime, of a-sc from lm results from preferential growth rather than preferential nucleation.
Anomalous Behavior During The Solidification of Silicon In The Presence of Impurities
Authors: Thompson Michael O. , Peercy P. S. 
Published: March 2011

ABSTRACTNanosecond pulsed laser irradiation of silicon results in the melting of the surface with subsequent solidification from a crystalline substrate. In the presence of impurities or alloys, the solidification dynamics are greatly affected by the nature of the impurities. Five classes of materials have been investigated: amorphous Si, mutually soluble alloys, high solubility impurities, low solubility impurities, and compound forming materials. Solidification of each of these classes of materials is discussed. Several anomalous kinetic regimes are observed, including explosive crystallization, surface nucleation of solid, and internal nucleation of melt. These results are interpreted in terms of thermodynamic modifications of the melting temperature in the alloy regions.
Mos Circuits on Silicon—Boron Phosphide—Silicon Multilayers
Authors: Dumin D. J. 
Published: March 2011

ABSTRACTOne approach to the fabrication of multiple silicon — insulator silicon layers that is compatible with existing silicon batch processing technology is to grow all of thelayers heteroepitaxially in a hydride reactor. We have grown multiple Si—Ins—Si layers using boron phosphide as the insulator. Up to 4 layers of BP—Si havebeen grown on silicon substrates and up to 2 layers have been grown on SOS substrates. MOS integrated circuits have been fabricated on the various Si layers. In general, the individual device quality and the performance of the ICs was lower as the number of layersincreased, however, even ICs fabricated on 4 layers of Si—BP—Si had characteristics comparable with SOS ICs. The growth process for production of the multiple heteroepitaxial films will be described. The characteristics of the ICs will be correlated with the film properties. Other possible candidates for insulators will be discussed.
Gallium Arsenide Layers Grown By Mbe on Germanium Islands on Insulator
Authors: Takai M. , Kodama Y. , Tanigawa T. , Kobayashi K. , Gamo K. , Namba S. 
Published: March 2011

ABSTRACTLocal variation of photoluminescence (PL) spectra for MBE GaAs grown on an insulating substrate with Ge-islands interface layers, prepared by zone melting recrystallization, has been investigated. The GaAs layers on the single crystalline Ge islands emit PL, the intensity of which was almost comparable to that of the GaAs layers on bulk Ge, while by a factor of 50 lower PL intensity was observed for the GaAs layers on Si02. PL spectra were found to show peak shifts due to the band-gap variation near the interface layer of GaAs, which was in good agreement with the residual strain obtained by microprobe Raman scattering for underlying Ge islands.
LPCVD Tungsten Deposition on Porous Silicon for Formation of Buried Conductors
Authors: Tsao S. S. , Blewer R. S. 
Published: March 2011

ABSTRACTWe report results on the feasibility of forming buried conductors under single crystal silicon using low pressure chemical vapor deposition of tungsten on the internal surfaces of porous silicon. The infiltration of tungsten into the pores depends on the porous silicon porosity, and on tungsten deposition process parameters such as deposition duration, total deposition pressure, and carrier gas species. The resulting tungsten-porous silicon layers were characterized by transmission and scanning electron microscopy, by Rutherford backscattering and x-ray spectroscopy and by four-point probe resistivity measurements.
Effect of Annealing on the Structure of Buried SiO2 Layers Formed By Elevated Temperature High Dose Oxygen Implantation
Authors: Krause S.J. , Jung C.O. , Wilson S.R. , Lorigan R.P. , Burnham M.E. 
Published: March 2011

ABSTRACTOxygen has been implanted into Si wafers at high doses and elevated temperatures to form a buried SiO2 layer for use in silicon-on-insulator (SOI) structures. Substrate heater temperatures have been varied (300, 400, 450 and 500°C) to determine the effect on the structure of the superficial Si layer through a processing cycle of implantation, annealing, and epitaxial growth. Transmission electron microscopy was used to characterize the structure of the superficial layer. The structure of the samples was examined after implantation, after annealing at 1150°C for 3 hours, and after growth of the epitaxial Si layer. There was a marked effect on the structure of the superficial Si layer due to varying substrate heater temperature during implantation. The single crystal structure of the superficial Si layer was preserved at all implantation temperatures from 300 to 500°C. At the highest heater temperature the superficial Si layer contained larger precipitates and fewer defects than did wafers implanted at lower temperatures. Annealing of the as-implanted wafers significantly reduced structural differences. All wafers had a region of large, amorphous 10 to 50 nm precipitates in the lower two-thirds of the superficial Si layer while in the upper third of the layer there were a few threading dislocations. In wafers implanted at lower temperatures the buried oxide grew at the top surface only. During epitaxial Si growth the buried oxide layer thinned and the precipitate region above and below the oxide layer thickened for all wafers. There were no significant structural differences of the epitaxial Si layer for wafers with different implantation temperatures. The epitaxial layer was high quality single crystal Si and contained a few threading dislocations. Overall, structural differences in the epitaxial Si layer due to differences in implantation temperature were minimal.
Formation of Silicon on Insulator Structures By Implanted Nitrogen
Authors: Nesbit L. , Stiffler S. , Slusser G. , Vinton H. 
Published: March 2011

ABSTRACTThe formation of a silicon-on-insulator (SOI) structure by implanting a high dose of N+ ions to form a buried Si3N4 layer is studied by transmission electron microscopy (TEM) and by secondary ion mass spectroscopy (SIMS). The SOI structure is formed by implanting silicon wafers with 7.5x1017 N+ ions/cm2 at 160 keV and at wafer temperatures of 400, 500, or 600°C. The implanted wafers are subsequently annealed at 1200°C for times ranging from 10 minutes to 2 hours. The microstructures and nitrogen distributions of the asimplanted and post-annealed wafers are examined in order to elucidate the development of the final microstructure.
Study of Dose and Dose Rate in the Implantation of Nitrogen Isotopes Into Si(100)
Authors: Namavar F. , Budnick J.I. , Fasihuddin A. , Sanchez F. H. , Hayden H. C. 
Published: March 2011

ABSTRACTIn this paper we address the issue of the dependence of Si3N4 formation on dose dose rate, and target temperature for high dose (up to 3 X 1018 N/cm2) implantation of nitrogen isotopel into Si targets. RBS results for high current (I≈ 30μ/cm2) and room temperature nitrogen implantations indicate that the nitrogen profile and the reduction of the backscattering signal from Si generally appear to be Gaussian. The nitrogen concentration exceeds Si3N4 stoichiometry at the higher doses. Read Camera results indicate the formation of polycrystalline α-Si3N4 and polycrystalline silicon for samples implanted at room temperature and annealed at 1200°C for 2 hours in a 10 Torr vacuum system. For samples implanted at 350 °C and annealed, there is evidence of crystalline α-Si3N4 with fiber texture structure.For low current (〈1 °A/cm2) and room temperature implantation, RBS indicates the formation of a layer whose N/Si ratio is the same as that of Si3N4. Furthermore, the nitrogen profile and the reduction of the Si backscattering signal appear flat. These results suggest that a uniform layer of Si3N4 can be produced providing the supply of nitrogen does not exceed the diffusion rate of nitrogen in compounds formed during implantation.
Thermal Stress During Zone-Melting-Recrystallization of Silicon on Insulator Films: The Origin of Subboundaries and In-Plane Orientation of SOI
Authors: Gibson J.M. , Pfeiffer L.N. , West K.W. , Joy D.C. 
Published: March 2011

ABSTRACTThe effect of thermal stress during zone-melting recrystallization of silicon on insulator films is considered. New experimental results from graphite-strip heated films are drawn upon. It is found that low-angle grain boundaries exhibit an inverse dependence between spacing and tilt angle. This is explained semiquantitatively by a model in which thermal stress induced film buckling is responsible for the existence of low-angle grain boundaries. It is also suggested that the predominance of the <100> orientation in these films is partly due to thermal stress and the elastic anisotropy of silicon. Thus thermal stress is proposed as the origin of the two major features of zone-melted films.
Integration of Semiconductor and Magnetic Bubble Devices: Soi on Garnet
Authors: Greve D.W. , Kryder M.H. , Rasky P.H.L. 
Published: March 2011

ABSTRACTSilicon on insulator (SOI) technology makes it possible to fabricate semiconductor devices on foreign substrates. In this paper, we present results for a process in which fieldeffect transistors are fabricated in recrystallized polysilicon on a magnetic bubble substrate. We report on the characteristics of the field effect transistors and the effect of the necessary processing steps on the magnetic properties of the substrate. A memory constructed in this hybrid technology would have very high density, multiple detectors for high speed, and direct logic level outputs.
Fabrication Process, Application and Future for An Elemental Level Vertically Integratedcircuit (Elvic)
Authors: Enomoto Tadayoshi 
Published: March 2011

ABSTRACTA new double-layered stacked LSI fabrication process has been developed for the purpose of realizing short fabrication turn-around time, high fabrication yield and high integration density. This process, which is named “Elemental Level Vertical Integrated Circuit (ELVIC)” technology, puts 2 convenfionally made LSI chips face to face andbonds them by thermal compression. The process includes, in addition to the conventionalLSI fabrication process, vertical interconnection (VI) formation in the upper and lower LSI layers, planarization of both upper and lower layer surfaces, and inter-level connections using pressure and heat. In the experimental version, about 52,000 10 x 10 μm2 Au-on-Ti VIs were connected on a 5 x 5 mm2 chip. Each pair of mated VIs is measured for tensile strength of 4 mg force. A 2-layer, 31-stage inter- CMOS/bulk ring oscillator consisting of p-channel MOSFETs on the upppr layerand nchannel MOSFETs on the lower layer has been built. Propagation delay time per stageis 1.86 nsec at the supply voltage of 5 V. ELVIC technology can produce a variety of benefits such as high production yield, doubling integration density, latch-up free CMOS LSIs, radiation damage free LSls, multi-function, and complete mixing of bipolar, CMOS andGaAs technologies.