bluuebunny/crossref_metadata_2025 huggingface dataset:
Some Aspects on the Formation of the Microstructure in Multipass Welds in Ferritic Ductile Cast Iron
Authors: Hällén G.
Published: March 2011

The microstructure obtained in the heat-affected zone (HAZ) and the carbide zone in the weld metal adjacent to HAZ has been studied in multipass welds in ferritic ductile cast iron. The effects of postweld anneal were also studied. The amount of martensite in the HAZ and the carbide zone can be reduced by the heating cycles of subsequent weld beads during multipass welding. The amount of martensite in the structure affects the graphite morphology after postweld annealing in both the HAZ and the carbide zone. It is also proposed that the graphite in the carbide zone, when arc-welding ductile cast iron with no or moderate preheat, is formed from cementite by grafitization.
The Influence of Microstructure on the Tensile Damage of Lamellar Grey Cast Iron
Authors: Fontaine A. , Zambelli G.
Published: March 2011

The 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

The 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

We 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

The 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

Some 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

Unlike 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

The 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

Seeding 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

Radiative 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

During 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

In 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

The 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

The 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

The 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

The 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

We 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

Epitaxial 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

We 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

X-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

Enhanced 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

The 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

We 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

The 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

Although 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

A 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

The 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
High Temperature Properties of Equialomic FeAl with Ternary Additions
Authors: Titran R. H. , Vedula K. M. , Anderson G. G.
Published: March 2011

The aluminide intermetallic compounds are considered potential structural materials for aerospace applications. The B2 binary aluminide FeAl has a melting point in excess of 1500 K, is of simple cubic structure, exist over a wide range of composition with solubility for third elements and is potentially self-protecting in extreme environments. The B2 FeAl compound has been alloyed with 1 to 5 at % ternary additions of Si, Ti, Zr, Hf, Cr, Ni, Co, Nb, Ta, Mo, W, and Re. The alloys were prepared by blending a third elemental powder with pre-alloyed binary FeAl powder. Consolidation was by hot extrusion at 1250 K.

Annealing studies on the extruded rods showed that the third element addition can be classified into three categories based upon the amount of homogenization and the extent of solid solutioning. Constant strain rate compression tests were performed to determine the flow stress as a function of temperature and composition. The mechanical strength behavior was dependent upon the third element homogenization classification.
Titanium Aluminides - An Overview
Authors: Lipsitt Harry A.
Published: March 2011

The object of this paper is to describe a coordinated research and development program which has been pursued by an Air Force-Industry-University team for more than twelve years. The focus of our attention has been on the development, processing, and engine testing of alloys based on intermetallic compounds, specifically on the aluminides of titanium, iron, and nickel. The titanium aluminides, Ti3Al and TiAl, are the materials with which we have been working the longest and on which development has proceeded the furthest. This Symposium has provided the first opportunity to review the progress of the titanium aluminide development programs sponsored by the Air Force and some of the engine testing efforts undertaken by the engine manufacturers.
Design of Ductile Polycrystalline Ni3Al Alloys
Authors: Liu C. T. , White C. L.
Published: March 2011

This paper provides a comprehensive review of current efforts on design of ductile polycrystalline Ni3AI alloys. Microalloying has proven to be very effective in alleviating the grain-boundary emibrittlement problem. The ductility and fabricability of Ni3Al (24 at. % Al) are dramatically improved by adding a few hundred parts per million of boron. The beneficial effect of boron is related to its unusual segregation behavior as predicted from the theory of grain-boundary cohesion developed by Rice, based on thermodynamic analyses. Alloy stoichiometry strongly influences grain-boundary chemistry, which, in turn, affects the boundary cohesion and overall ductility of Ni3Al.

The solid-solution hardening of Ni3AI depends on the substitutional behavior of alloying elements, atomic size misfit, and the degree of nonstoichiometry of the alloy. Hafnium additions are very effective in improving high-temperature properties of ternary Ni3Al (Al + Hf = 24 at. %) doped with boron. Alloying with <2% Hf substantially increases the yield stress and raises the peak-strength temperature. In addition, hafnium substantially improves creep properties and oxidation resistance. The Ni3Al aluminides truly represent a new series of heat resistant materials which do not depend on chromium for oxidation resistance.
The Oxidation of Nickel-Aluminum and Iron-Aluminum Alloys
Authors: Cathcart John V.
Published: March 2011

The high-temperature oxidation behavior of several ordered alloys in the Ni-Al and Fe-Al systems is reviewed with special emphasis on Ni3Al and NiAl. Ordering influences oxidation through its effect on the activities of the alloy components and by changing the point defect concentration in an alloy. Three categories of Ni-Al alloys are distinguished based on Al content and oxidation behavior. A characteristic feature of the oxidation of high-aluminum Ni-Al and Fe-Al alloys is the formation of voids in the substrate at the oxide-metal interface. The mechanism of void formation and its suppression by minor additions of oxygen-active elements is discussed. A brief description of the effect of preoxidation on the reactions of Ni3Al-base alloys in SO2/O2 environments is also included.
Interatomic Interaction in Transition and Noble Metal Alloys and the Stability of the Ordered State
Authors: Dementyev V. M. , Kozlov E. V. , Kolodeznaya S. F.
Published: March 2011

The nature and the role of the pair interatomic interaction of the noble and transition metal ordering alloys are considered. The determining role in the electron susceptibility in the behaviour of the interatomic interaction is shown. The important role of the Fermi surface local geometry in the definition of superstructure periods is established. Illustrating calculations are made. It is shown that in the noble and transition metal alloys with complicated Fermi surface the oscillations of the pair interatomic interaction are of essentially nonfriedel character.
Computer Modelling of Laser Annealing
Authors: Baeri P.
Published: March 2011

Heat flow calculations, based on the main assumption that the energy of the incident pulse is instantaneously and locally converted into heat, are used to review the results of laser pulse annealing and impurities behaviour in ion implanted semiconductors. The crystallization behaviour of amorphous layers, the velocity of the solid-liquid interface and impurity redistribution are detailed with the main emphasis on the relevance of the parameters (laser wavelen gth, pulse duration and energy density, substrate temperature, etc.) that can be experimentally controlled. Comparison with the latest experimental results is also given.
Solute Segregation and Dynamics of Solid-Phase Crystallization In in and Sb-Implanted Silicon
Authors: Narayan J. , Olson G. L. , Holland O. W.
Published: March 2011

Time-resolved-reflectivity measurements have been combined with transmission electron microscopy (cross-section and plan-view), Rutherford backscattering and ion channeling techniques to study the details of laser induced solid phase epitaxial growth in In+ and Sb+ implanted silicon in the temperature range from 725 to 1500 °K. The details of microstructures including the formation of polycrystals, precipitates, and dislocations have been correlated with the dynamics of crystallization. There were limits to the dopant concentrations which could be incorporated into substitutional lattice sites; these concentrations exceeded retrograde solubility limits by factors up to 70 in the case of the Si-In system. The coarsening of dislocation loops and the formation of a/2<110>, 90° dislocations in the underlying dislocation-loop bands are described as a function of laser power.
Light Absorption Effects on the Nd Laser Annealing of Ion Implanted Silicon
Authors: Baeri P. , Bapbarino A.E. , Campisano S.U. , Grimaldi M.G. , Foti G. , Rimini E.
Published: March 2011

The crystallization onset and the annealing thresholds have been nmeasured as a function of the absorbed energy density in ion implanted amorphous silicon irradiated with nanosecond Nd pulse. Thin amorphous layers (∼500 Å) require higher thresholds ccapared with thick (∼4000 Å) amorphous layers. This result can be explained in terms of balance between absorbed energy and heat flow. For a given thickness of the amorphous layer the thresholds depend on the absorption coefficient of the amorphous material. This last parameter has been varied frcm 104 to 102 CM−1 by low temperature (T<400°C) pre-treatment of the ion implanted sample. The observed drastic variations of both crystallizazion and annealing thresholds agree well with nunerical evaluation of heat flow.
Silicon Melts During Pulsed Ruby Laser Annealing
Authors: Stritzker B , Pospieszczyk A , Tagle J. A.
Published: March 2011

The lattice temperature of silicon was measured during pulsed ruby laser annealing (-20 ns pulse, spot diameter ≥ 5 mm) using a classical time of flight method to determine the velocity distribution of Si atoms evaporated from the hot surface. The maximum of this Maxwell type distribution was used to calculate the temperature of the Si surface. The resulting lattice temperatures vary between 1200 and 2500 K for energy densities between 1.0 and 2.0 J/cm2 , i.e., Si is molten for energy densities ≥ 1.4 J/cm2 . This result clearly supports the strictly thermal annealing model [1] and contradicts the non-thermal-equilibrium model [2] as well as Raman measurements [3].
Periodic Surface Damage in Germanium: The Spectrum in K→ Space and its Theoretical Interpretation
Authors: Young Jeff F. , Sipe J. E. , Gallant M. I. , Preston J. S. , Van Driel H. M.
Published: March 2011

The Fourier transforms of the grating-like damage patterns formed on the surface of Ge by single 1.06μm YAG laser pulses reveal a great deal of information about the damage structure. A theory is presented based on scattering from surface roughness which accurately accounts for both the spacing and orientation of the fringes produced at various angles of incidence by beams of different polarizations.
Residual Defects in Virgin and Implanted Si After Laser Processing
Authors: Mesli A. , Goltzene A. , Muller J.C. , Meyer B. , Schwab C. , Siffert P.
Published: March 2011

EPR, photocarrier cyclotron resonance and DLTS measurements have been performed on laser-annealed Si wafers.

In virgin Si, an isotropic EPR line at g1 = 2.0055± 0.0005 and a carrier lifetime decrease, assessed by cyclotron resonance, are correlated to the creation of vacancy complexes associated to Oxygen.

In implanted Si, only defects due to the tailing effect of implantation process are observed by DLTS. These levels can be divided into two groups, one of them is stronglycorrelated with the implanted parameter. They are ascribed to primary or complex associations of point defects.
Modelling of CW Laser Annealing of Multilayer Structures
Authors: Calder I.D. , Sue R. , Aly Emad-Eldin A.A.
Published: March 2011

A thermal model is developed for cw laser annealing of multilayer structures. Each layer has arbitrary thickness, thermal conductivity and optical properties. Steady state conditions with no phase transition are assumed. A procedure is presented for obtaining the temperature distribution in any system and explicit integral expressions are developed for the two and three layer cases. Results are calculated for the Si/glass and Si/SiO2 /Si systems.
Pulsed Laser Annealing of R.F.Sputtered Amorphous Si : H.Films, Doped with Arsenic
Authors: Fogarassy E. , Stuck R. , Toulemonde M. , Siffert P. , Morhange J.F. , Balkanski M.
Published: March 2011

Arsenic doped amorphous silicon layers have been deposited on silicon single crystals by R.F.cathodic sputtering of a silicon target in a reactive argon-hydrogen mixture, and annealed with a Q-switched Ruby laser. Topographic analysis of the irradiated layers has shown the formation of a crater, due to an evaporation effect of material which could be related to the presence of a high concentration of Ar in the amorphous layer. RBS and Raman Spectroscopy showed that the remaining layer is not recrystallised probably due to inhibition by the residual hydrogen. However, it was found that arsenic diffuses into the monocrystalline substrate by laser induced diffusion of dopant from the surface solid source, leading to the formation of good quality P-N junctions.
CW Annealing Techniques for Junction Formation in Ge
Authors: Lorenzo J.P. , Soda K. J. , Eirug Davies D.
Published: March 2011

CW scanned Argon laser annealing is used to form photo diodes in single crystal Boron implanted germanium. The starting material is doped n–type to 4 × 1015 cm−3 and oriented 2° off the <100>. For annealing, a substrate temperature of 250°C is employed in conjunction with a beam spot diameter of 50 μm and scan speeds in the vicinity of 1 cm/sec. Pyrolytic oxides are deposited to provide a protective and antireflective coating. Devices are fabricated and display dark leakage characteristics of the order of ∼ 10−4 A/cm2 which is comparable to diodes made by more conventional techniques.
Material-Process Interactions in the Annealing of Gallium Arsenide
Authors: Lawrence Anderson C.
Published: March 2011

This review article provides an overview of the current understanding of the physical mechanisms involved in the annealing of ion implanted GaAs by thermal techniques and by CW and pulsed laser and electron beams. The successfulness of these techniques is evaluated in terms of the electrical and optical properties of the annealed layers. Promising areas of investigation for the improvement of the electrical properties of n-type layers produced by pulsed annealing are identified.
Diffusion of Si in GaAs From a Thin Si Film by Pulsed Laser Irradiation
Authors: Nissim Y. I. , Greiner M. , Falster R. J. , Gibbons J. F. , Chye P. , Huang C.
Published: March 2011

The diffusion of Si into GaAs from a thin source has been investigated. Electron beam evaporated Si films were deposited on chromium–doped GaAs wafers. Pulsed irradiation from a Q–switched Nd:YAG laser resulted in the formation of n+ layers. After metal evaporation these layers displayed nonalloyed ohmic contact behavior of very low contact resistance (5×10−7 Ω−cm2 ) and good thermal stability at 300°C. SIMS analysis of these layers revealed a steplike Si profile and significant chromium redistribution within the laser induced molten layer. A major improvement in surface morphology was obtained using Si02 encapsulants.
A New Electron Beam Polishing Technique for Heteroepitaxial Thin Films
Authors: Tobin S. P. , Greenwald A. C. , Wolfson R. G. , Wong T. T.
Published: March 2011

We have developed a novel technique for improving the morphology of as-grown monocrystalline thin films on foreign substrates. A pulsed electron beam briefly heats the surface of the film above its melting temperature, allowing surface tension in the liquid to erase irregular features. Crystallinity of the layer is preserved by rapid resolidification with the underlying material acting as a seed. Pulse polishing has been applied to two heteroepitaxial systems exhibiting rough as-deposited surfaces: germanium on silicon and cadmium telluride on mica. In both cases the surface morphology was dramatically improved while crystallinity and other critical properties of the layers were maintained. We believe this technique has potentially wide application to many thin film systems and should allow a greater degree of freedom in the growth conditions for heteroepitaxial thin films.
Supersaturated Substitutional Solid Solution after Solid Phase Epitaxial Regrowth by Incoherent Light Scanning.
Authors: Pedulli L. , Correra L.
Published: March 2011

Supersaturated substitutional solid solutions of 2×101531P+ /cm2 implanted at 10 keV in (100) Silicon were obtained after solid phase epitaxial regrowth using a scanning beam of incoherent light. The main results are: a) the maximum P+ concentration exceeds of about 5 times the maximum solid solubility at the temperature reached by the sample; b) the carrier concentration profile shows a complete dopant activation without diffusion of the implanted ions; c) an improvement of minority carriers diffusion length in the bulk is often observed; d) the values of carrier mobilities are similar to those obtained after liquid phase regrowth by pulsed ruby laser; e) a very good recovery of the damage is obtained: Rutherford backscattering spectra show that the dechanneling fraction is very close to the value of virgin samples and Trasmission Electron Microscopy analysis shows that the residual damage consists of dislocation loops of about 30 Å diameter confined in a region at about 500 Å depth.
Dual Electron Beam Processing System for Semiconductor Materials
Authors: McMahon R.A. , Davis J.R. , Ahmed H.
Published: March 2011

This paper describes a semiconductor processing system using two electron beams. One beam provides uniform heating of the bulk of the specimen, whilst the other performs localized heating, for example as a spot, a line beam, or as an inset scan. The annealing of localized regions in ion-implanted silicon and SOS, by local heating above the bulk temperature, illustrates the application of the system. Other applications of the systems are also considered.
A Study of Intermetallic Compound Development In Nickel-Tin Interfacial Zones
Authors: Allen Charles W. , Fulcher Mark R. , Rai Amarjit S. , Sargent Gordon A. , Miller Albert E.
Published: March 2011

Interdiffusion and intermetallic formation in Ni-Sn interfacial zones are examined by X-ray diffraction in samples prepared by electroplating of Sn at room temperature. For the case of plating directly onto electropolished nickel, only very sluggish formation of Ni3Sn4 was observed at 190 C. In contrast, when the nickel surface is chemicaly or chemically-abrasively activated prior to plating, a thin layer of Ni3Sn forms at the initial interface at room temperature, and subsequent annealing at 100 and 190 C produces all intermetallics predicted by the equilibrium phase diagram including Ni3Sn, indicating that the absence of Ni3Sn usually observed arises from its failure to nucleate.
Fracture Mechanics of Interface Failure
Authors: Kendall Kevin
Published: March 2011

Interfaces are important in ceramic and other composite materials because they can be used to control cracks, the major source of weakness and unreliability in brittle solids. Brittle materials fracture catastrophically, but may be converted into tough composites by the injection of interfaces which retard or deflect the cracks. This paper examines the behaviour of cracks at interfaces and demonstrates several mechanisms for crack control in brittle systems. Crack stopping, dislocation formation, and crack deflection at interfaces have been illustrated by experiments on rubber models and analysed by the energy balance theory of fracture.
Determination of Time-Dependent Plastic Properties of Metals by Indentation Load Relaxation Techniques
Authors: Hannula Simo-Pekka , Stone Donald , Li Che-Yu
Published: March 2011

Load relaxation testing has been demonstrated to be useful for characterizing the time dependent plastic properties of metals. However, for testing of small material volumes, such as thin film metallizations, thin films, and contact surfaces, conventional load relaxation techniques cannot be used. For such applications an indentation test offers an attractive means for obtaining data necessary for materials characterization. This work shows that an indentation load relaxation test is experimentally feasible for thin film testing. Experiments on brass and beryllium copper samples with or without a gold/nickel plating illustrate different relaxation properties of the substrates and the surface layers. Furthermore, results of experiments on some fcc metals suggest rather simple relations between the conventional uniaxial load relaxation (LR) test and the indentation load relaxation (ILR) test.
Acid-Base and Electrostatic Contributions to the Adhesion of Polymers to Metal and Ceramic Substrates
Authors: Fowkes Frederick M.
Published: March 2011

The strength of interfacial bonding between polymers and inorganic substrates is very appreciably enhanced when polymers are acidic and substrates are basic, or vice versa. The interaction is of two kinds, an increased thermodynamic work of adhesion resulting from large exothermic interactions at the interface, and an increased tensile strength resulting from electrical charge injection into the polymer from the substrate.

The exothermic interfacial interactions between acidic and basic sites are easily measured by calorimetry or by infrared spectral shifts. The enthalpies of adsorption can be correlated and predicted by the Drago equation, −Δ H = CACB+ EAEB, where the CA and EA for the acidic member can be measured by enthalpies determined with basic molecular probes of known CB and EB. Heats of adsorption of polymers onto inorganic substrates are precisely predictable with the above equation once E and C values are known for the polymer and substrate.
Effect of Interfacial Characteristics of Metal Clad Polymeric Substrates on Electrical High Frequency Interconnection Performance
Authors: Bhasin K. B. , Romanofsky R. R. , Ponchak G. E. , Liu D. C.
Published: March 2011

Etched metallic conductor lines on metal clad polymeric substrates are used for electronic component interconnections. Significant signal losses are observed for microstrip conductor lines used for interconnecting high Frequency (above 20 GHz) devices. At these frequencies, the electronic signal travels closer to the metal-polymer interface due to the skin effect. Copper-teflon interfaces were characterized by SEM and AES to determine the interfacial properties. Data relating roughness of the copper film to signal losses was compared to theory. Films used to enhance adhesion, were also found, to a lesser extent, to contribute to these losses.
Direct Concentration Measurement of Hydrogen Electromigration Using Nuclear Reaction Analysis
Authors: Benenson R. E. , Berning P. , Wielunski L.
Published: March 2011

Lateral concentration profiles of hydrogen (1H) have been measured using nuclear recoil analysis on electrolytically charged metal (V, Nb, Ta) foils subjected to current densities of order 103 amps/cm2 for various times in order to study the electromigration of hydrogen. Initially uniformly loaded foils exhibited a dramatic redistribution of the hydrogen. Numerical analysis of these data using the conventional solution of the electromigration equation is used to extract the hydrogen effective charge (Z*) from the steady state data and the diffusion coefficient from the time-dependent data. The nuclear technique permits rapid and accurate direct concentration measurements capable of distinguishing surface and subsurface transport.
Universal Binding Energy Relations in Metallic Adhesion
Authors: Ferrante John , Smith John R. , Rose James H.
Published: March 2011

Rose, Smith, and Ferrante have discovered scaling relations which map the adhesive binding energy calculated by Ferrante and Smith onto a single universal binding energy curve. These binding energies are calculated for all combinations of Al(111), Zn(0001), Mg(0001), and Na(110) in contact. The scaling involves normalizing the energy by the maximum binding energy and normalizing distances by a suitable combination of Thomas-Fermi screening lengths. Rose et al. have also found that the calculated cohesive energies of K, Ba, Cu, Mo, and Sm scale by similar simple relations, suggesting the universal relation may be more general than for the simple free-electron metals for which it was derived. In addition, the scaling length was defined more generally in order to relate it to measurable physical properties. Further this universality can be extended to chemisorption and molecular binding. The implications of this scaling have been explored and have produced some interesting results and verifications. A simple and yet quite accurate prediction of a zero temperature equation of state (volume as a function of pressure for metals and alloys) is presented. Thermal expansion coefficients and melting temperatures are predicted by simple, analytic expressions, and results compare favorably with experiment for a broad range of metals. All of these predictions are made possible by the discovery of universality in binding energy relations for metals. Finally some results of other researchers concerning universality In Van der Waals forces are referred to