bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Influence of Microstructure on the Tensile Damage of Lamellar Grey Cast Iron
Authors: Fontaine A. , Zambelli G. 
Published: March 2011

ABSTRACTThe rupture behaviour of lamellar grey cast iron under tension depends on the overall damage suffered by the heterogeneous microstructure. In order to quantify the influence of microstructural components on the rupture behaviour of the material, it is therefore preferable to apply “Damage Mechanics” concepts rather than “Linear Fracture Mechanics”. In this preliminary study the damage process is assumed to be isotropic and two parameters are considered; firstly a damage limit σ0 and secondly, a damage rate B. Measurements made on a grey cast iron, cast in three different cross sections, show that these damage parameters may be used to separate the contributions of the graphite network and the matrix wich interact in the degradation process of the heterogeneous microstructure of lamellar grey cast iron.
A Relationship between the Crystalization Rate and the Structure and Strength Characteristics or the Fe-C-Cr, Fe-C-Cr-Ti and Fe-C-Cr-Ce Alloys Subjected to Directional Solidification
Authors: Fras Edward , Guzik Edward , Karamara Antoni 
Published: March 2011

ABSTRACTThe paper present the results of investigation into the directional solidification of Fe-C-Cr alloys containing about 30% Cr and various contents of carbon. The main types of the structure of these alloys were given and the zone of a coupled growth of the eutectic was determined as well as an effect of the growth rate on the interfacial distance λ and on the tensile strengthof these alloys. It was proved that the additions of titanium and cerium considerably reduce the distance λ and increase the tensile strength, which in the case of an Fe-Cr-C-Ce alloy can reach a value of about 3250 MPa. The alloys solidified in the form of bars and plates which also enabled the determination of an effect of angle between the axis of the carbide fibres and the direction of loading on the ultimate tensile strength. of these alloys.
Anisotropic Second Harmonic Generation Induced in Silicon and
Germanium by Picosecond and Nanosecond Laser Pulses
Authors: Litwin John A. , Van Driel Henry M. , Sipe John E. , Litwin John A. 
Published: March 2011

ABSTRACTWe have performed experimental and theoretical studies of the origins of
anisotropic second harmonic generation observed in reflection from (111) and
(100) faces of crystal Ge and Si. Results, using 25 psec and 20 nsec 1.06
and 0.53 μm pump beams allow us to conclude that induced plasmas have no
role in the effect and that the mechanism for the nonlinearity is associated
with quiescent surface dipolar or bulk quadrupolar effects. Dispersion in
the anisotropic behaviour is presented and the application of anisotropic
harmonic generation to structural determinations of Si and Ge during laser
annealing will be discussed.
Evolution of Silicon Irradiated with Femtosecond
Pulses
Authors: Hulin D. , Tanguy C. , Combescot M. , Bok J. , Migus A. , Antonetti A. 
Published: March 2011

ABSTRACTThe total energy reflected from a silicon single crystal irradiated by a 100
femtosecond laser pulse is measured. We observe a plasma resonance at
wavelengths of 620 nm and 310 nm indicating electron-hole densities higher
than 1022 cm. The result are interpreted using a highly non linear theory.
Very short relaxation times are observed and attributed to electron-hole
collisions. The study of the light scattered by the silicon surface shows a
sharp decrease at high fluences that we interprete by a possible screening
of irregularities by emitted electrons .A pump-test experiment is also
reported showing the emission of Si particles. A possible mechanism for the
extraction of these particles is proposed.Laser pulses, of a duration of the order of 100 femtosecondsare a very
unique tool to study the physical mechanisms of energy transfer from the
electron-hole (e-h) plasma to the lattice in semiconductors. The incident
photons are absorbed by the electrons, creating a hot and dense
electron-hole plasma and breaking covalent bonds thus softening the lattice.
After the pulse, the electron-hole pairs recombine, the plasma expands, and
through electron-phonon interaction the energy is transferred to the
lattice. Several experiments have recently been reported using femtosecond
pulses to create a high density e-h plasma in silicon and study its time
evolution [1,2,3]. The use of such intense and short pulses raises the
possibility of breaking so many covalent bonds that the melting temperature
of the crystal can be lowered [4,5] significantly. In a first period, a new
phase is obtained, with atoms almost immobile (having a low kinetic energy)
but imbedded in a dense hot plasma. In a time of the order of several
electron-phonon relaxation times (τe-p) the energy is transferred to the
atoms and the normal liquid phase is obtained. The understanding of the
exact nature of the melting induced by very short pulses relies on a good
knowledge of the energy transfer from the laser pulse to the sample. In this
paper, we report measurements of the total amount of energy of a 100 fs, 620
nm and 310 nm of wavelengths, light pulse reflected by a silicon single
crystal and its variation with pulse intensity (self reflectivity with no
test beam). We also give measurement of the light scattered from the surface
to see changes of the surface roughness. Finally, we give the result of a
pump-test experiment showing the formation of a "blackhole" in the center of
the incident spot, as already reported by other authors [6].
Picosecond Photon-Solid Interaction
Authors: Kurz H. , Bloembergen N. 
Published: March 2011

ABSTRACTSome of the fundamental aspects of pulsed laser interactions with
semiconductors are reviewed within the frame of recent experimental work
with picosecond laser pulses. Main emphasis is placed on data obtained in
space-time resolved measurements of transmission and reflectivity of
picosecond pulse irradiated silicon at different probing wavelengths. Four
distinct interaction regimes can be defined, depending on the fluence of the
laser pulse. Special attention is devoted to the phase transition from solid
to liquid state at the surface. The optical heating model is found to be
valid even on a time scale of picoseconds. Firm data of the electron-hole
plasma density and lattice temperature are derived. The thermal nature of
the phase transition is confirmed.
A Simple Model for the Transient, Enhanced Diffusion of
Ion-Implanted Phosphorus in Silicon
Authors: Morehead F. F. , Hodgson R.T. 
Published: March 2011

ABSTRACTUnlike As, B as well as P implanted into Si exhibits transient, enhanced
diffusion. For example, when P implants are annealed for times of ~1 s at
temperatures > 900°C, we observe a large movement of dopant toward the
furnace of the Si wafer which is nearly independent of temperature
1050-1200°C. Once the temperature rises above 1200-1250°C the diffusion is
similar to that normally observed. We model the experimental results as a
transient, enhanced diffusion of a mobile component, about half the total
phosphorus implant, distributed deeper in the bulk than the total P
distribution. This mobile component may be linked to a large
super-saturation of self-interstitials produced by the 50 keV implantation,
which are expected to be left deeper in the bulk than the total dopant
profile.
High-Voltage Electron Microscopy Investigation of Subgrain
Boundaries in Recrystallized Silicon-On-Insulator Structures
Authors: Baumgart H. , Phillipp F. 
Published: March 2011

ABSTRACTThe microstructure of high-quality recrystallized Si films on
SiO2 substrates produced by CO2 laser induced
zone-melting has been investigated by high voltage electron microscopy
(HVEM). Subgrain boundaries represent the major defects in these
recrystallized films. The origin of the subboundaries has been traced to
periodic internal stress concentrations occurring at the faceted growth
interface. These highly localized stresses cause plastic deformation of the
growing single crystal film by nucleation of an array of slip dislocations.
The mechanism responsible for the formation of subgrain boundaries has been
revealed to be polygonization, where thermally activated dislocations
rearrange themselves into the lower energy configuration of the low angle
grain boundary.
Subboundary Free Submicronic Devices on Laser-Recrystallized
Silicon Oninsulator
Authors: Auberton-Herve A.J. , Joly J.P. , Hode J.M. , Castagna J.C. 
Published: March 2011

ABSTRACTSeeding from bulk silicon (lateral epitaxy) has been used in Ar+ laser
recrystallization to achieve subboundary free silicon on insulator areas. On
these areas C.MOS devices have been performed using almost entirely the
standard processing steps of a bulk micronic C-MOS technology. n -MOS
transistors with channel length as small as 0.3 um have shown very small
leakage currents. This is attributed especially to the lack of
subboundaries. A 40 % increase in the dynamic performances in comparison
with equivalent size C-MOS bulk devices has been obtained (93 ps of delay
time per stage for a 101 stages ring oscillator with 0.8 μm of channel
length). This is the best result presented so far on recrystallized SOI. No
special requirements are needed in the lay out of the circuit with the
chosen seed structure. Furthermore an industrial processing rate for the
laser recrystallization processing has been achieved using an elliptical
laser beam, a high scan velocity (30 cm/s) and a 100 μm line to line scan
step (a 4' wafer in 4 minutes).
Computer Modeling of Lateral Epitaxial Growth Over
Oxide
Authors: Wilson Lynn O. , Celler G. K. 
Published: March 2011

ABSTRACTRadiative melting of Si with an extended stationary heater and its
crystallization are modeled numerically. The two-dimensional model provides
the velocity and shape of the solid-liquid interface, above and below a
buried oxide structure with slit-shaped openings. The results show
qualitative agreement with the experimental data. Superheating and
undercooling are included in the calculation and the amount of superheating
is confirmed experimentally.
Kinetics of Radiative Melting of Si
Authors: Celler G. K. , Trimble L. E. , Wilson Lynn O. 
Published: March 2011

ABSTRACTDuring radiative melting, a silicon surface breaks up into coexisting solid
and liquid regions with spacing dependent on incident flux, thermal
parameters, and crystalline properties of the sample. The space-averaged
reflectivity becomes a function of the incident photon flux, profoundly
affecting the transfer of energy and the rate of melting.We explain time evolution of the molten surface morphology and present data
relating depth of melting to the incident photon flux for bulk Si and Si
with buried oxide. The data prove the existence of a steady state transition
region in which meltingis only superficial and time-independent.
The Influence of Point Defects on Diffusion and Gettering in Silicon
Authors: Gösele U. , Tan T. Y. 
Published: March 2011

ABSTRACTIn a first part, we deal with the influence of intrinsic point defects (vacancies and self-interstitials) on self- and impurity diffusion in silicon. Estimates of the diffusivities and thermal equilibrium concentrations of vacancies and self-interstitials are given. In a second partwe discuss the influence of point defects on the diffusion and precipitation of different types of metallic impurities in various gettering schemes as well as on the nucleation and growth of SiO2 precipitates.
Ebic evidence for Carbon-based Gettering in EFG Silicon
Authors: Gleichmann R. , Kalejs J. P. , Asta D. G. 
Published: March 2011

ABSTRACTThe efficiency of solar cells fabricated from low-oxygen, high-carbon, EFG silicon ribbon can be improved by pre-annealing the ribbon at 1200°C prior to processing. TEM analysis shows that the increased efficiency is not related to a relaxation of the defect structure. Rather, EBIC investigations demonstrate a continuous reduction of the recombination activity of in-grown crystal defects (dislocations, grain boundaries) with increasing duration of the anneal. Since C is the only element in supersaturation at the annealing temperature, a model is suggested in which metallic contaminants are gettered at small carbon clusters.
Effect of Heavy Doping on the Nucleation and Growth of Bulk Stacking Faults in Silicon
Authors: Pearce C. W. , Kook T. , Jaccodine R. J. 
Published: March 2011

ABSTRACTThe effect of heavily doping silicon3with boron (up to 9.0×19/cm3) or antimony and arsenic (up to 1.0×19/cm3) on the nucleation and growth of bulk stacking faults (BSF) was investigated by the use of three-step heat treatment; 700°C-24 hrs., 900 °C 24 hrs., and 1050 °C up to 48 hrs.The length and density of BSF were determined by optical microscopy after a Secco or Schimmel etch of cleaved specimens. From the effect of heavy doping on the density of BSF we imply the nucleation rate is doping level dependant. The effect of the low temperature (700°C) heat treatment time on the relationship between the density and the length of BSF indicates that the growth of BSF may be a supply-limited process. The effect of a high temperature (1300°C) oxygen dispersion treatment was also investigated. The results are analyzed in terms of a vacancy model.
Effect of Dopant Concentration on the Growth of Oxide Precipitates in Silicon
Authors: Matsumoto Satoru , Ishihara Ichiro , Kaneko Hiroyuki , Harada Hirofumi , Abe Takao 
Published: March 2011

ABSTRACTThe dependences of dopant species and concentrations on the growth of oxide precipitates have been studied using transmission electron microscopy. Doping species are phosphorus, antimony and boron. Samples were annealed at 800°C and 850°C for 24∼384hr in dry nitrogen. In phosphorus-doped silicon, the precipitate density is independent of doping concentration and the growth of precipitate obeys the three-quarter power law. The enhancement of the precipitate growth is observed in antimony-doped silicon. On the other hand, the precipitate growth is suppressed in heavily boron-doped silicon as compared with that of lightly boron-doped silicon. This indicates the generation of excess silicon interstitials in heavily boron-doped silicon.
Diffusion, Complexing and Precipitation of Transition Metals in Silicon
Authors: Weber Eicke R. 
Published: March 2011

ABSTRACTThe diffusion, solubility, complexing, and gettering of transition metals in silicon are reviewed with special emphasis on the observed chemical trends. 3d metals appear dominantly on interstitial sites in thermal equilibrium. Their diffusivity and solubility increases markedly with atomic number. Going from the 3d metals vertically down in the periodic table, a clear trend towards substitutional solution is obvious. Observation of deep level defects, complexing and gettering is strongly dependend on the respective mobility of the metal atoms. Understanding of the thermodynamics of complexing and gettering allows to define heat treatment procedures favourable to minimize detrimental effects from transition metals in silicon.
Specular Scattering in Electrical Transport in the Thin Tilm System CoSi2/Si
Authors: Hensel J. C. , Tung R. T. , Poate J. M. , Unterwald F. C. 
Published: March 2011

AbstractWe have investigated electrical transport in thin films of CoSi2 at low temperatures as a function of film thickness and observe in conductivity a size effect much smaller than seen heretofore indicative of a high degree of specularity in the boundary scattering. This in large part owes to the unique characteristics of these films, i.e., they are single crystal and continuous down to ∼60Å thickness with long bulk scattering lengths (≈1000Å) in transport at liquid He temperatures and have nearly atomically perfect interfaces.
Epitaxy of Aluminium Films on Semiconductors by Ionized Cluster Beam
Authors: Yamada I. , Palmstrøm C. J. , Kennedy E. , Mayer J. W. , Inokawa H. , Takagi T. 
Published: March 2011

AbstractEpitaxial Al films have been deposited onto the clean surface of single-crystal Si by ionized cluster beam (ICB) at room temperature. Thermal stability of the film has been examined by SEM, AES depth profiling, ion backscat. tering/channeling, and electrical characterization of the Al-Si interface. It was found that the ICB Al film on Si substrate was remarkably stable up to 550°C although pure Al was used. Alloy penetration at the interface, shift of barrier height, degradation of crystalline quality and development of annealing hillocks on the surface were not observed after the heat treatment. Extremely long electromigration life time was also confirmed. Epitaxial growth on GaAs(100) substrate was attempted and preliminary results are given.
Electrical Transport through Metal Contacts to In0.53Ga0.47As Thin Films
Authors: Lu Pong-Fei , Tsui D. C. , Cox H. M. 
Published: March 2011

AbstractWe report two phenomena observed in the electrical transport through metal contacts to In0.53Ga0.47 As thin films. First, a surface accumulation layer of electrons is found at the oxide-In0.53Ga0.47 As interface of Pb-oxide-In0.53Ga0.47 As tunnel junctions, suggesting that the surface Fermi level is not pinned in In0.53Ga0.47 As, and ideal ohmic contacts to n- In0 53Ga0.47 As can be made by using low work function metals. Second, we observed a strong oscillatory conductance on the I-V characteristic of electrical transport through In- In0.53 Ga0.47As contacts, with a period approximating the LO-phonon energy of In0.53Ga0.47As. We explain the data by successive phonon emission in the high field transport of ballistic electrons and point out that the experiment is a solid state analogue of the Franck-Hertz experiment.
The Characterization of Thin Films and Layered Structures Using X-RAY Absorption and Reflection at Grazing Incidence
Authors: Heald S. M. , Tranquada J. M. , Welch D. O. , Chen H. 
Published: March 2011

AbstractX-rays at grazing incidence have a short, controllable penetration depth and are well suited as a probe of surface and interface structures. This paper examines the possibility applying grazing-incidence reflectivity and Extended X-Ray Absorption Fine Structure (EXAFS) measurements to such systems. Results are presented for an Al-Cu couple for which both high resolution reflectivity and interface EXAFS measurements are made. The latter results are the first interface specific EXAFS data to be reported. Distinct changes in both signals are observed upon annealing, demonstrating the potential of the techniques.
The XPS Searchlight Effect: A New Analytical Tool for Layered Structures, Epitaxy, and Interfaces
Authors: Egelhoff W. F. 
Published: March 2011

AbstractEnhanced core-level peak intensities at angles corresponding to the internuclear axes among the near surface atoms is a characteristic feature of angle resolved XPS. This phenomenon, which is due to constructive interference in forward scattering of photoelectrons, acts, in effect, as a search-light allowing relatively easy mapping out of the structural arrangement atoms in the near-surface region. Examples which illustrate the usefulness of the XPS searchlight effect are presented.
X-ray Investigation of Strained Metal-Hydrogen Superlattices
Authors: Miceli P. F. , Zabel H. , Cunningham J. E. 
Published: March 2011

AbstractThe properties of strained superlattices can be studied in a tunable fashion by dissolving hydrogen interstitially in strain free Nb/Ta metal superlattices. We report on a first investigation of a Nb/Ta 20 Å superlattice loaded with hydrogen in-situ in a high temperature x-ray furnace. After hydrogen uptake the ± 1 satellite reflections show pronounced asymmetries, indicating a hydrogen density distribution which is modulated by the superlattice periodicity.
Solid State Reaction of Sputter Deposited Crystalline Multilayers of Ni and Zr
Authors: Unruh K. M. , Meng W. J. , Johnson W. L. , Thakoor A. P. , Khanna S. K. 
Published: March 2011

AbstractWe have prepared sputtered metallic films comprised of alternating layers of pure Ni and Zr to a total thickness of several microns. Due to the negative beat of mixing of crystalline Ni and Zr and a significant intermixing rate we have been able to form an amorphous Ni-Zr phase by a solid state reaction. In this work we report the conditions under which a substantial fraction of amorphous material may be formed. The extent of the reaction itself as a function of time has also been monitored.
Structure Analysis of Ni-Silicides Formed in Lateral Diffusion Couples
Authors: Chen S. H. , Barbour J. C. , Zheng L. R. , Carter C. B. , Mayer J. W. 
Published: March 2011

AbstractThe microstructures of the silicide Ni5Si2, which formed in self-supporting Ni-Si lateral-diffusion couples has been studied using high-resolution electron microscopy. Two different polymorphs (or polytypes) for Ni5Si2 have been observed. The actual composition of one polytype is confirmed to be Ni31Si12, while the other one has not yet been identified. Variations in the distribution of the two polytypes, as observed in the present study, may account for the composition range of Ni5Si2 in the Ni-Si phase diagram.
Heavy Ion induced Damage and Disorder in Intermetallic Compounds with the B2 Structure
Authors: Brimhall John L. , Kissinger Homer E. 
Published: March 2011

ABSTRACTAlthough the B2-type intermetallic compounds, NiAl, FeAl, NiTi and FeTi all maintained a high degree of order during irradiation, metastable phase formation was observed. Dislocation loops and network developed in NiAl and FeAl during irradiation and a nickel rich, fcc phase, most likely disordered Ni3Al, formed in NiAl after high doses. The build-up of constitutional vacancies (excess vacancies on Ni sites) and subsequent elemental partitioning of Ni and Al can explain the formation of a nickel rich phase in NiAl. No metastable phases formed in FeAl. Dislocation loop structures did not develop in NiTi or FeTi, rather a transformation to an amorphous phase occurred at relatively low doses. The amorphous transformation results when the free energy of the crystal lattice containing a high defect concentration exceeds the free energy of the amorphous configuration.
Dislocation Core Structure and the Normal Yield Behavior of L12 Ordered Alloys
Authors: Tichy G. , Vitek V. , Pope D. P. 
Published: March 2011

ABSTRACTA rapid increase of the yield stress with increasing temperature, often observed in L12 ordered alloys, is commonly called the “anomalous flow behavior”. This phenomenon is believed to result from the thermally activated transformation of the core of 1/2<110> screw dislocations from a glissile form to a sessile form at high temperatures. It is shown here that another class of L12 alloys exists in which these two forms of the screw dislocation core are not available. These are the alloys in which the APB on {111} planes is not stable and the atomistic studies of screw dislocations in such alloys show that their cores are always sessile. The yield stress of these alloys then increases with decreasing temperature and no increase at high temperatures occurs. Such behavior has been observed, for example, in Pt3Al. This “normal” behavior is analogous to that of b.c.c. metals and a theory of the temperature dependence of the yield stress has been developed along the same lines as in the case of b.c.c. metals. Comparison of this theory with measurements on Pt3Al single crystals shows a good agreement.
Hydrogen Embrittlement of Ordered Alloys
Authors: Kuruvilla A. K. , Stoloff N. S. 
Published: March 2011

ABSTRACTThe susceptibility to hydrogen embrittlement has been investigated in two L12 superlattices, (Fe, Ni)3V and boron-modified sub-stoichiometric Ni3Al and in a B2 superlattice, FeCo-V. The relationship between ordering and hydrogen embrittlement is explained on the basis of characteristic dislocation structure in the ordered lattice and hydrogen-dislocation interactions