bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Temperature Oxidation of β-NiAl
Authors: Doychak Joseph K. , Mitchell T. E. , Smialek J. L. 
Published: March 2011

ABSTRACTThe oxidation of single crystal β-NiAl has been studied primarily using electron microscopy. Oriented metastable Al2O3phases form during transient oxidation at 800°C. Specific orientation relationships exist on all metal orientations studied and are a result of the small mismatch along aligned close-packed directions in the cation sublattices of the metal and oxide. Transformation of the metastable Al2O3, phases at 1100°C results in an oxide morphology described as the “lacey” structure of α-Al2O3scales. This structure results from impingement of oriented patchei α a-Al2O3as the transformation initiates and moves radially parallel to the sugfhce. Scale growth occurs by diffusion along high angle grain boundaries. A drastic reduction in oxidation rate accompanies the change in oxide morphology.
Ordering Behavior and Corrosion Properties of Ni-Mo and Ni-Mo-Cr Alloys
Authors: Tawancy H. M. , Asphahani A. I. 
Published: March 2011

ABSTRACTNi-Mo alloys containing 26–28 wt. pct. Mo are known for their excellent corrosion properties in reducing environments. When exposed to temperatures in the range 600°C to 800°C, however, these alloys undergo a longrrange ordering reaction from disordered fcc lattice to ordered Dla superlattice. This ordering phenomenon has been found to have detrimental effects on corrosion properties. Also, alloys based on the Ni-16Mo-16Cr system undergo a long range ordering reaction from disordered fcc lattice to ordered Pt2Mo-type superlattice in the temperature range of 400° to 600°C. However, in contrast to the case of Ni-Mo alloys, ordering in the Ni-Mo-Cr alloys has some beneficial effects on the aqueous corrosion properties. This difference in behavior between the Ni-Mo alloys and the Ni-Mo-Cr alloys is discussed interms of the ordering characteristics determined from transmission electron microscopy and diffraction, X-ray microanalysis in the scanning transmission electron microscope and Auger electron spectroscopy.
Magnetic Studies of Ni3Al(Fe) Compounds
Authors: Sekula S. T. , Kerchner H. R. , Thompson J. R. , Leventouri Th. 
Published: March 2011

ABSTRACTSeveral samples of the ordered intermetallic compound with the Ll2 structure and chemical composition NiO.75-xAl0.25-xFe2x (doped with 0.2 at. % B) have been studied over an Fe compositional range 0 ≤ 2x ≤ 0.20. Stoichiometric Ni3Al is known to be a strongly exchange-enhanced-material, forming a giant moment system when Fe impurities are introduced in trace amounts. For the greater Fe concentrations employed in this work, more conventional ferromagnetic systems are obtained. Well below the ferromagnetic Curie temperature Tc the samples exhibit a spontaneous moment in small magnetic fields and at higher fields the isothermal magnetization data show a clear tendency toward saturation. Magnetic investigations using vibrating-sample techniques permitted measurements over the temperature interval from 4.2 K to 800 K in fields up to 5.0 T. The Curie temperature was found to increase from ∼50 K for the Fe-free sample in the series to 410 K for the limiting concentration of 12 at. % Fe in the Ll2 structure. Samples with higher Fe content up to 20 at. % contain a second, disordered fcc phase with Tc ≃ 715 K. Peaks in the temperature dependence of the lattice parameter observed in x-ray studies yield Tc values in reasonable agreement with the magnetic measurements.
Influence of Microstructure on the Corrosion Behavior of a Ni-Si Alloy
Authors: Kumar P. 
Published: March 2011

ABSTRACTNickel-based alloys with over 7 percent silicon have excellent corrosion resistance to sulfuric acid, oleum and sulfate-ion-containing environments. This alloy is characterized by the presence of intermetallic Ni3Si (beta) and Ni5Si2 (gamma) phases in Ni-Si solid solution (alpha) matrix. The corrosion resistance is provided by the coarse intermetallic phases. Size of intermetallic phases is dependent on the processing condition and the heat treatment. The corrosion resistance can be changed by heat treatment.Results of corrosion tests are explained in terms of microstructural features.
Modulated Microstructures in β-Phase Alloys
Authors: Wayman C. M. 
Published: March 2011

ABSTRACTMany ordered β-phase alloys of the B2 or D03 types exhibit unusual diffraction patterns and images when examined in the transmission electron microscope. These effects include “extra” diffraction spots, diffuse scattering, satellites, “tweed microstructures, spinodal decomposition and the formation of incommensurate phases. Examples of these phenomena will be presented and discussed. Although most of the β-alloys also undergo a martensitic transformation at some lower temperature it will be argued that the above effects are not “premartensitic” or precursory in nature. However many of them can be related to certain properties of the β-phase such as elastic anisotropy, a soft phonon mode and electronically driven instabilities.
Melting Phenomena and Interfacial Instability Associated with Laser Irradiation
Authors: Narayan J. 
Published: March 2011

ABSTRACTThe work on annealing of displacement damage, dissolution of boron precipitates, dopant redistribution and formation of constitutional supercooling cells using pulsed ruby and dye laser irradiation is reviewed in order to provide convincing evidence for melting as a primary mechanism of laser annealing. The nature of the liquid-solid interface and the interfacial instability during laser-induced rapid crystal growth are considered in detail. Solute concentrations after laser annealing can far exceed retrograde solubility limits, but there is a critical concentration above which a planar liquid-solid interface becomes unstable and breaks into cellular structures. The solute concentrations and cell sizes associated with this instability have been studied as a function of crystal-growth velocity and these results compared with calculations of the perturbation theory. Good agreement between the experimental results and the theory was obtained when the dependence of the distribution coefficient upon crystal growth velocity was taken into account in the calculations.
Fundamentals of Energy Transfer During Picosecond Irradiation of Silicon
Authors: Bloembergen N. , Kurz H. , Liu J.M. , Yen R. 
Published: March 2011

ABSTRACTThe fundamentals of energy transfer in semiconductors during and following pulsed laser excitation are reviewed within the frame of results obtained in picosecond laser experiments. This paper discusses the theoretical processes as well as the experimental evidence, which sets limits of electron and lattice temperature of irradiated silicon. Simple thermal melting is the most probable explanation for the laser induced phase transitions observed.
Picosecond Laser Pulse Induced Damage in Crystalline Silicon
Authors: Merkle K. L. , Uebbing R. H. , Baumgart H. , Phillipp F. 
Published: March 2011

ABSTRACTPicosecond laser pulse irradiation of single crystalline Si can produce severe damage, including amorphisation. Morphology changes are studied by means of optical and high-voltage-electron microscopy and are found to depend on energy fluence, surface orientation, and wavelength. The detailed analysis of the damage distributions and thresholds lead to the conclusion, that energy-confinement precedes the introduction of structural changes, which are formed by rapid quenching from the liquid state.
Laser and Ion Beam Mixing Cr and Ni + Cr Films on Cu.
Authors: Draper C. W. , Jacobson D. C. , Gibson J. M. , Poate J. M. , Vandenberg J. M. , Cullis A. G. 
Published: March 2011

ABSTRACTThin films of Cr and Cr films capped with Ni–8V have been magnetron sputter deposited on both single crystal and polycrystalline Cu and Cu alloy substrates. Surface alloying has been accomplished with scanning second harmonic Q-switched Nd-YAG and single shot Q-switched Ruby lasers and with 1 MeV Xe ions. The films and surface alloys have been characterized with RBS and channeling, AES and sputter profiling, optical microscopy, SEM, TEM and glancing angle XRD. Surface alloys containing as much as 50 at. % Cr have been produced. Following laser melting it is possible to produce substitutional solid solutions of Cr in Cu far in excess of equilibrium values.
Studies of Laser-Alloyed Zr-Containing Surface Layers
Authors: Draper C. W. , Den Broeder F. J. A. , Jacobson D. C. , Kaufmann E. N. , Mcdonald M. L. , Vandenberg J. M. 
Published: March 2011

ABSTRACTThin films of Cu on Zr and of Zr on Fe, Ni, Al, V, and Ti have been laser-pulse alloyed with the substrate metals using a raster-scanned Q-switched Nd:YAG laser. The high quench rates from the liquid state attendant to laser-pulse melting can promote the retention of a variety of metastable alloy phases. Structure and composition of the surface alloy layers of submicron thickness were studied with Rutherford backscattering (RBS)/channeling spectroscopy, optical and transmission electron microscopy and glancing angle x-ray diffraction (XRD). Composition profiles are compared with expected liquid-state diffusivities and structures are related to properties of bulk alloys. For example, in the well-known glass-forming system Cu-Zr, an amorphous phase was formed which crystallized upon annealing above Tc. In the Zr-Ti system, which shows complete solid solubility across the binary phase diagram in both the α and β phases, the hexagonal α-phase alloy is formed. Additional results on these and other systems are described below.
Phase Segregation During Laser Melting of Ni-Si and Co-Si Films
Authors: Bosch M.A. , Dayem A.H. , Harrison T.R. , Lemons R.A. 
Published: March 2011

ABSTRACTIn this study Ni-Si and Co-Si films were deposited on fused quartz substrates by coevaporating the metal and silicon. The source separation and deposition rate were chosen to produce a composition range across the substrate. These films were then melted with a scanned cw argon laser beam. This results in a dramatic phase segregation that is readily observed in a light or scanning electron microscope. For the Ni-Si sample two phases separate into irregularly shaped regions up to ≈l10μm size. Electron microprobe measurements indicate that one phase is NiSi2 while the other is pure Si. With the Co-Si sample two phases segregate into narrow stripes that usually follow the temperature gradient produced by the scanned laser beam. The composition analysis indicates that these phases are CoSi and CoSi2. A possible cause for this morphology is discussed.
Beam Recrystallized Silicon-On-Insulator Devices
Authors: Lam H. W. 
Published: March 2011

ABSTRACTBeam-recrystallized silicon-on-insulator is an attractive material for VLSI integrated circuit and flat panel display applications. This paper describes the electrical characteristics that are unique to MOSFETs fabricated in this material. The back-interface between the silicon and the insulator significantly affects the leakage current by acting as a possible leakage path, depending on the charge at the back interface and the doping concentration in the silicon close to the back interface. In addition, enhanced arsenic diffusion along grain boundaries can cause short circuits between the source and the drain of an n-channel MOSFET. Evidence of such enhanced diffusion are presented as well as means to reduce the impact of the problem. It is shown that molecular hydrogen can be used to passivate the grain-boundaries in the recrystallized silicon material, thereby increasing the carrier mobility. A profile of the carrier mobility as a function of depth from the surface of the silicon is presented, showing that the carrier mobility is not reduced significantly, even close to or at the back interface.
The Gentle Electronic Nature of Pulsed Beam Annealing, or Does It Really Go Superfluid?
Authors: Van Vechten J. A. 
Published: March 2011

ABSTRACTUntil recently two theories of what may be occurring during pulsed laser/electron/ion beam annealing of Si, Ge, GaAs, and other semiconductors enjoyed credence. One held that the material became hot and underwent normal thermal melting. The other held that the material annealed in the presence of a hot dense plasma of excited free carriers, electrons and holes. A closer examination of previous experiments, as well as new experiments, particularly those of Marquardt et al., which indicate an absence of free carrier absorption in the infrared, make both these theories untenable. They also make possible a more sophisticated understanding of what really is happening. The present status of this subject is reviewed. In particular the available evidence that the plasma excited by the pulsed radiation undergoes a boson condensation to a superfluid phase is described.
Grain Enlargment in Polysilicon on Insulating Substrates Induced by Q-Switched Nd:Yag Laser Irradiation
Authors: Falster R. J. , Eggermont G. E. J. , Gibbons J. F. 
Published: March 2011

ABSTRACTA systematic investigation of the formation of large grained rings in polysilicon by Q-switched laser irradiation has been performed. Parameters varied in this study were polysilicon thickness, substrate temperature and underlying oxide thickness. Increasing ring widths were obtained for increasing substrate temperature, polysilicon film thickness and underlying oxide thickness. The width of these rings was found to be independent of incident laser power above a certain threshold value. Surface morphology and the occurrence of cracking and ablation in these films as a function of these parameters was also investigated.
Uniform and Directed Crystallization of Deposited a­Si on Glass Substrates at Linear Velocities Of 1 to 20 Meters Per Second
Authors: Bensahel D. , Auvert G. , Nguyen V. T. , Rozgonyi G. A. 
Published: March 2011

ABSTRACTIt has been found that careful control of the laser power and scan speed will convert deposited a­Si into continuous lines of uniformly crystallized silicon. Two solid phase “explosive” crystallization front velocities of 1000 cm/sec and 1400 cm/sec have been experimentally determined by matching the laser scan velocity with the runaway a–c phase boundary. If solid phase explosive crystallization is suppressed by pre-annealing, then a liquid assisted runaway crystallization velocity of 220 cm/sec is observed, as well as a continuous furnace-like crystallization process at 250 cm/sec.
Silicon Devices Fabricated by Using Laser Irradiation Process
Authors: Tamura M. , Natsuaki N. , Miyao M. , Ohkura M. , Murai F. , Takeda E. , Minagawa S. , Tokuyama T. 
Published: March 2011

ABSTRACTThe advantages and disadvantages of both pulsed and cw scanned laser processing for Si devices are discussed. In particular, adaptions of laser processes for MOSFETs and bipolar structures are described from the viewpoint of active layer annealing. Moreover, MOSFETs fabricated in laser induced grown Si films on Si substrates having SiO2 patterns by bridging epitaxy, are discussed, as a function of sample structures, film formation conditions and laser irradiation conditions.
Photoluminescence of Pulsed Ruby Laser Annealed Crystalline and Ion Implanted GaAs
Authors: Lowndes Douglas H. , Feldman Bernard J. 
Published: March 2011

ABSTRACTIn an effort to understand the origin of defects earlier found to be present in p–n junctions formed by pulsed laser annealing (PLA) of ion implanted (II) semiconducting GaAs, photoluminescence (PL) studies have been carried out. PL spectra have been obtained at 4K, 77K and 300K, for both n–and p–type GaAs, for laser energy densities 0 ≤ El ≤ 0.6 J/cm2. It is found that PLA of crystalline (c−) GaAs alters the PL spectrum and decreases the PL intensity, corresponding to an increase in density of non-radiative recombination centers with increasing El. The variation of PL intensity with El is found to be different for n– and p–type material. No PL is observed from high dose (1 or 5×1015 ions/cm2 ) Sior Zn-implanted GaAs, either before or after laser annealing. The results suggest that the ion implantation step is primarily responsible for formation of defects associated with the loss of radiative recombination, with pulsed annealing contributing only secondarily.
Multiply Scanned Electron Beam Annealing of Si Implanted GaAs
Authors: Bujatti M. , Cetronio A. , Nipoti R. , Olzi E. 
Published: March 2011

ABSTRACT.Experimental results obtained by multiply-scanned electron beam annealing (MEBA) of Si implanted semi-insulating GaAs are presented and compared with results obtained by thermal annealing. A tentative model for Cr redistribution during MEBA treatment is presented which can explain the 100% activation without compensation threshold and the high drift mobility obtained for low Si doses, almost independent of the Cr content of the crystal.
Epitaxial Ge/GaAs Heterostructures by Scanned CW Laser Annealing of a-GE Layers on GaAS
Authors: Greene J.E. , Cadien K.C. , Lubben D. , Hawkins G.A. , Erikson G.R. , Clarke J.R. 
Published: March 2011

ABSTRACTEpitaxial regrowth of Ge/GaAs heterostructures by scanned laser annealing of amorphous Ge films on GaAs substrates has been studied as a function of laser power and scan rate. At least eight regimes representing different film regrowth characteristics were observed. Of these, two were of primary interest. At low powers (between~1.6 and 3.2 W for a beam diameter of~40 μm) and scan rates between 1 and 400 cm/sec, polycrystalline Ge with a (100) preferred orientation was formed by an “explosive” crystallization mechanism. At higher powers, and over a scan rate range of 25 to 400 cm/sec, single crystal metastable (GaAs)1−x Gexalloys were obtained by liquid phase regrowth. Typical film resistivities, ρ, were as follows: as-deposited ρ=180Ωcm; polycrystalline films, ρ=3 × 10−2 Ωcm; single crystal films,ρ=9×10−4Ωcm.
A Laser Triggered Self-Sustaining Metals-Compound Semiconductor Transition for AlSb
Authors: Andrew R. , Baufay L. , Pigeolet A. , Laude L.D. 
Published: March 2011

ABSTRACTThe preparation of AlSb thin films by pulsed laser annealing of Al/Sb sandwiches is studied in order to resolve some past controversy about the temperature rise induced by the laser pulse. Using 1000 Ȧ thick two layer films supported by TEM grids, we investigate the energy threshold for complete transformation as a function of pulse duration from 15 nsec to 100 msec, and of ambient temperature from −100°C to 250°C.We thence calculate the temperature effect directly induced by the laser to be about 930°C, or approximately the melting point of the metals, whereas inert gas furnace anneals of comparable films show transformation at this temperature occuring only in about 100 sec. We discuss the isoenergetic nature of the system for short laser pulses and the role of the heat of transformation, and thus conclude that the reaction is thermally triggered by the laser pulse but is to some extent self-sustaining via the heat of transformation locally distributed. This model is also shown to have equal validity for the systems CdTe, CdSe and AlAs.
Time Resolved Transmission and Reflectivity of Pulsed Ruby Laser Irradiated Silicon
Authors: Lowndes Douglas H. , Jellison G. E. , Wood R. F. 
Published: March 2011

ABSTRACTThe time resolved optical transmission, T (atλ = 1152 nm), and reflectivity, R (at 633 nm and 1152 nm), have been measured for n-type single crystalline silicon (c-Si) during and immediately after pulsed ruby laser irradiation (λ = 693 nm, FWHM pulse duration 14 nsec), for a range of pulsed laser energy densities, El. The T is found to go to zero, and to remain at zero, for a period of time that increases with increasing El, in apparent disagreement with earlier measurements elsewhere that used semi-insulating Si and a different pulsed laser wavelength. Measured reflectivities during the high R phase agree within experimental error with reflectivities calculated from the optical constants of molten Si. Quantitative agreement is also found between both our T and R measurements and detailed time– and El-dependent results of thermal melting model calculations.
Transient Heating with Graphite Heaters for Semiconductor Processing
Authors: Fan John C. C. , Tsaur B-Y. , Geis M. W. 
Published: March 2011

ABSTRACTTransient heating with graphite heaters has been shown to be very useful in several important semiconductor processing applications. Using stationary and/or movable heaters, we have obtained excellent results in the annealing of ion-implantation damage in Si and GaAs, preparation of epitaxial Ge1−xSix on Si substrates, and recrystallization of Si films on insulators. The advantages of graphite heaters include their ready scalability in area to commercial wafer size and their low capital cost. These heaters are also easily machinable, and their temperature can be rapidly varied. When fully developed, this heating technique should provide an inexpensive and versatile method for commercial processing of many semiconductor materials.
Characterization of Ion-Implanted Si Rapidly Annealed with Incoherent Light
Authors: Benton J. L. , Celler G. K. , Jacobson D. C. , Kimerling L. C. , Lischner D. J. , Miller G. L. , Robinson Mc.D. 
Published: March 2011

ABSTRACTIrradiation of Si wafers for 5 to 10 sec with high intensity tungsten halogen lamps produces complete recovery of the displacement damage resulting from ion implantation. Data for two different thermal cycles are presented, with As and B implant doses ranging from 1013 to 1016 ions cm−2. Sheet resistance measurements combined with Rutherford backscattering indicate full electrical activation of dopants with very little diffusion. Carrier lifetimes measured by a photoconductive method and by diode reverse recovery compare favorably with furnace annealing data, and capacitance transient spectroscopy reveals a low density of defects in the junction depletion region. These results combined with the inherent advantages of low cost and high efficiency make Rapid Thermal Annealing ideally suited for VLSI device fabrication.
Rapid Annealing of Ion Implanted Silicon Structures using a Radiant Light Source
Authors: Harrison H.B. , Grigg M. , Short K. T. , Williams J.S. , Zylewicz A. 
Published: March 2011

ABSTRACTAsimple radiant light source has been employed to rapidly anneal ion implanted silicon structures at temperatures >1000° C for times of the order of 1–200 sec. Rutherford backscattering and channeling analysis indicated good crystalline lattice recovery and the formation of metastable solid solutions of Sb in Si without observable diffusion broadening of the implanted profile. Diode arrays have been successfully annealed using the technique, with no observable deterioration of the surrounding oxide mask.
The Reaction Kinetics of Liquid 60/40 Sn/Pb Solder With Copper and Nickel: A High Temperature X-Ray Diffraction Study
Authors: Dehaven Patrick W. 
Published: March 2011

AbstractWith proper sample preparation, high temperature x-ray diffraction can be used to study in-situ the reactions occurring at a solder/metal interface. We have applied this technique to an investigation of the reaction kinetics between copper and nickel metal and 60/40 Sn/Pb solder. The copper and nickel are shown to follow similar pathways, each having a complex reaction profile that involves an initial “hold” of little reactivity, followed by a two-step diffusion controlled reaction. Activation energies were obtained from Arrhenius-type plots, and result in values of 6.8 kcal/mole for the nickel/solder reaction, and 13 kcal/mole for the copper/solder reaction. These results are compared with those obtained by previous investigators, and discussed in terms of the growth of the different intermetallic phases.