bluuebunny/crossref_metadata_2025_split huggingface dataset:
Grain Structure Interaction Between Cold and Hot Sputtered Aluminum Films
Authors: O'Meara David L. 
Published: March 2011

AbstractThe factors affecting the second layer grain structure of a two-aluminum-layer sputtered film were investigated with the use of a computer-aided experimental design and analysis program. A cold aluminum layer followed by a hotter aluminum layer has been described in the literature as a means of improving metal step coverage. Several factors were screened to determine the most important parameters by which the first layer influences the second. The two-layer interactions were determined by using scanning electron microscope (SEM) analysis to measure final grain structures. A model was generated from the experimental results that shows the influence of the first layer grain size on the second layer if the second sputter deposition is made above ∼300°C. The influence increases at higher temperatures. The results will be compared to grain growth models found in the literature.
The Effect of Deposition and Annealing Conditions on the Microstructure of Al-Cu and Al-Cu-Si Thin Films
Authors: Park M. , Krause S. J. , Wilson S. R. 
Published: March 2011

AbstractThe effect of deposition temperature and the addition of Si to sputter deposited Al-Cu thin-film microstructure was studied with transmission electron microscopy. Films were studied in the as-deposited and annealed condition. The effects of thermal treatment were studied with in-situ hot stage microscopy. Al2Cu (θ) precipitated at the grain boundaries and the sublayer interface. At higher deposition temperatures, with alloy composition in single phase region (Al-1.5 wt.%Cu), Al2Cu precipitated during cooldown. At lower temperatures, in the two phase Al-0 region, Al2Cu precipitated during deposition. The addition of Si caused formation of Si precipitates and retarded Al2Cu precipitation during deposition or cooldown.
On the Structure of Transformation Interfaces
Authors: Khalid F. A. , Edmonds D. V. 
Published: March 2011

AbstractThe transformation interfaces of some well known products of austenite decomposition in steels, namely pearlite, and proeutectoid grain boundary allotriomorphic cementite and Widmanstatten cementite, have been examined by TEM. This has been accomplished by using high- Mn high- C alloys that decompose at intermediate ageing temperatures but in which the untransformed parent austenite phase remains stable at room temperature, thus preserving the transformation interface. In conventional steels the residual austenite would undergo the martensite reaction, destroying the interface in the process. Defects in the interface have been analysed and related to intersections with stacking faults in the parent austenite phase. The nature and occurrence of these stacking faults, and their effect on the transformation, is considered.
Role of Interfaces in Coarsening and Grain Growth
Authors: Marsh S. P. , Glicksman M. E. 
Published: March 2011

AbstractTheories of late-stage phase separation are discussed from the perspective of statistical mean-field approaches, whereby the material interfaces are assumed to interact with the appropriate average microstructural environment. For coarsening of two- and three-dimensional phases, recent progress is presented for selecting the most appropriate averages that characterize the microstructural environment surrounding a domain. The effective mean field, as well as the average interaction distance over which transport occurs, may be determined self-consistently by imposing global constraints that reflect the microstructural phase fractions and by using explicit spatial and ensemble averages of the matrix transport fields. Comparison of new theoretical coarsening rates with liquid-phase sintering experiments show good agreement over a wide range of phase fractions. Extension of this approach to grain growth, which involves more complex topological interactions, is also discussed.
Implications of Interface Structure on the Elastic Properties of Metallic Multilayers-The Case of the Supermodulus Effect
Authors: Jankowski Alan F. 
Published: March 2011

AbstractThe existence of the supermodulus effect, an enhancement in the elastic modulus of artificially layered metal films, was discovered more than a dozen years ago. Yet the detailed nature of this effect remains a puzzling phenomena. Implications of the interface structure on the elastic properties of gold-nickel multilayers are investigated using x-ray diffraction and high resolution electron microscopy.
Atomic-Level and Effective Elastic Moduli at Grain Boundaries
Authors: Alber I. , Bassani J. L. , Khantha M. , Vitek V. , Wang G. J. 
Published: March 2011

AbstractThe relationship between atomic structure and elastic properties of grain boundaries is investigated from both discrete and continuum points of view. A heterogeneous continuum model of the boundary is introduced where distinct phases are associated with individual atoms and possess their atomic level elastic moduli determined from the atomistic model. The complete fourth-order tensors of both the atomic-level and the effective elastic moduli are determined, where the latter are defined for sub-blocks from an infinite bicrystal and are calculated here for a relatively small number of atom layers above and below the grain boundary. These effective moduli are determined exactly for the discrete atomistic model, while only estimates from upper and lower bounds can be determined for the continuum model. Comparison between the atomistic results and those for the continuum model establishes the validity of this definition of elastic properties for heterogeneous structures at these scales. Furthermore, these comparisons as well as algebraic properties of the fourth-order tensor of moduli lead to criteria to assess the stability of a given grain boundary structure.
Time Resolved Spectra of Raman and Thermal Emission During Pulsed Laser Heating of Silicon
Authors: Von Der Linde D. , Wartmann G. , Kemmler M. , Zhu Zhen-He 
Published: March 2011

ABSTRACTLaser heating of crystalline silicon is investigated with 10 ns laser pulses at 532 nm Raman spectra below the transition threshold show distinct shifts to low frequencies. The absence of line shifts at higher energy is due to a time resolution artifact. Temperatures evaluated from frequency resolved anti-Stokes/Stokes ratios are in agreement with the temperature estimated from line shifts, and provide clear evidence that the surface reaches the melting point. These conclusions are confirmed by independent measurements of the thermal emission. Time-resolved pyrometry also provides the temperature evolution of the liquid phase.
Stress Effects on Raman Measurements of Pulsed Laser Annealed Silicon
Authors: Jellison G. E. , Wood R. F. 
Published: March 2011

ABSTRACTIt has recently been shown that the front surface region of the silicon lattice is severely strained during pulsed laser irradiation. This uniaxial strain reduces the symmetry of the front surface region, resulting in additional shifts and splittings of the phonon frequency and changes in the Raman scattering tensor. It is shown that, for the case of pulsed laser irradiation, the phonon frequency is increased, and the 3-fold degenerate optical phonon is split into a singlet and a doublet. The changes in the Raman scattering tensor make it non-symmetric, and generally invalidate the technique used by Compaan et al. to determine the cross section experimentally. The complications introduced by the presence of stress during pulsed laser annealing, coupled with the temperature dependence of the optical and Raman tensors, make a simple interpretation of the Stokes to anti-Stokes ratio in terms of lattice temperature extremely unreliable.
Melting Phenomena and Impurity Redistribution During Pulsed Laser Irradiation of Amorphous Silicon Layers
Authors: Narayan J. , White C. W. , Holland O. W. 
Published: March 2011

ABSTRACTwe have investigated microstructural changes and phase transformations in 30Si+, 75As+, 63Cu+, and 115In+ implanted amorphous silicon layers as a function of pulse energy density. Cross-section electron microscopy studies have revealed the formation of two distinct regions, large and fine polycrystalline regions below the threshold for “defect-free” annealing. The fine polycrystalline region is formed primarily by explosive recrystallization, and occasionally by bulk nucleation and growth. The impurity redistribution in the large and fine polycrystalline regions were determined by Rutherford backscatterinq measurements. Large redistributions of impurities in the large poly region are consistent with velocity of solidifications of 3–5 ms−1. The nature of impurity redistributions in the fine poly region as a function of distribution coefficient provides information on the details of liquid phase crystallization phenomena.
Laser Quenching of Amorphous Si from the Melt Containing Dopants
Authors: Campisano S. U. , Jacobson D. C. , Poate J. M. , Cullis A. G. , Chew N. G. 
Published: March 2011

ABSTRACTThe formation of amorphous Si by the quench of a thin surface layer melted by fast UV laser irradiation has been investigated. The starting (111) surface layers were either pure or doped with As, Bi, In and Te by implantation. The asimplanted samples were recrystallized by ruby laser irradiation resulting in surface accumulation of Bi,In and Te. For the same UV irradiation condition, the amorphous layer formed in As, Bi, In or Te doped Si is about twice the thickness of the amorphous layer formed on pure Si. In the presence of the surface accumulation of Bi, In or Te, the amorphization results in an inward segregation of the dopant. For In, a very thin metal layer ˜15Å thick, is formed 150Å beneath the amorphous surface. These results show that the amorphous-liquid interfacial segregation coefficients for Bi, In or Te are less than unity and that the amorphous solidification proceeds from the surface and bottom of the liquid layer.
Short Time annealing of As and B Ion Implanted Si using Tungsten-Halogen Lamps
Authors: Sedgwick T. O. , Kalish R. , Mader S. R. , Shatas S. C. 
Published: March 2011

ABSTRACTB and As implanted Si wafers have been thermally annealed by an array of tungsten halogen lamps at 1000–1200°C for 1–10 sec. Annealing above 1100°C leaves the crystal free of extended defects in all cases as determined by TEM. An enhanced diffusion is observed above normal values characterized by a low activation energy for both As and B samples. This enhanced diffusion is transient and occurs within about one second since the RBS and SIMS dopant profiles are identical for 1 sec and a 10 sec anneal.
Ultrafast UV-Laser Induced Oxidation of Silicon
Authors: Orlowski T.E. , Richter H. 
Published: March 2011

ABSTRACTA new low temperature method of forming high quality patterned silicon dioxide (SiO2) layers up to a thickness of 1 μm on silicon substrates is presented. UV pulsed laser excitation in an oxygen environment is utilized. IR absorption spectroscopy, CV and IV measurements are employed to characterize the oxide films and the Si-SiO2 interface. No shift but a significant broadening of the Si-O stretching mode compared with thermally grown oxides is found indicating that the laser grown oxide is stoichiometric but with a higher degree of disorder. From CV measurements we deduce a fixed oxide charge near the Si-SiO2 interface of 6×1010/cm2 for oxides that have been thermally annealed in O2 following the laser induced growth making this material a candidate for applications in semiconductor devices.
Solid Silicon at the Melting Temperature is Crystalline
Authors: Biegelsen D. K. , Nemanich R. J. , Fennell L. E. , Street R. A. 
Published: March 2011

ABSTRACTRecently it has been proposed that solid silicon at the melting temperature is amorphous. There is no known case of a solid for which an amorphous structure is the equilibrium state. Silicon thin films on insulating substrates, when heated radiantly, melt inhomogeneously and provide an accessible high temperature system for a study of a solid coexisting with its melt. Using the intensity, energy distribution and polarization of Raman scattering from silicon lamellae, we have proved that the equilibrium phase is in fact crystalline. Furthermore, we give strong evidence that the solid regions have {100} texture at Tm.
Single Crystalline Germanium Island on Silicon Dioxide by Zone Melting
Authors: Takai M. , Tanigawa T. , Gamo K. , Namba S. 
Published: March 2011

ABSTRACTSingle crystalline germanium islands on SiO2 have been formed by zone melting with graphite strip heaters. Two types of geometrical patterns for islands were successfully used to obtain large single crystalline islands. Most germanium islands were found to be single crystal and the predominant orientation was (100). Electron concentrations of 1016 - 1018/cm3 with Hall mobility of 3 × 103 − 1 × 103 cm2 /Vsec were obtained for single crystalline germanium islands. Gallium Arsenide layers, grown by molecular beam epitaxy, on the germanium islands were found to emit photoluminescence, the intensity of which was almost comparable to that of gallium arsenide layers on bulk germanium crystals.
Faceted Melting and Superheating of Crystalline Si Irradiated with Incoherent Light
Authors: Celler G. K. , Jackson K. A. , Trimble L. E. , Robinson McD. , Lischner D. J. 
Published: March 2011

ABSTRACTWe report and analyze the breakup of a crystalline silicon surface into solid and molten faceted segments by radiative heating. Melting starts at discrete sites since there is a nucleation barrier requiring superheating of the surface. Once started, the melt remains localized and does not encompass the entire surface because of the changes in optical properties of Si upon melting. It is estimated that superheating by <0.5 K should be sufficient to stabilize faceted melt regions spaced 200 μm apart. The preliminary measurements, however, indicate superheating by several degrees.
Lateral Solid Phase Epitaxy of Silicon Over Oxide
Authors: Roth J.A. , Olson G.L. , Hess L.D. 
Published: March 2011

ABSTRACTWe review recent progress in the growth of siliconon-insulator films by lateral solid phase epitaxy. The temperature dependence of the rates of random crystallization and solid phase epitaxy are used to predict the maximum growth of Si over oxide achievable by this technique. Actual overgrowth distances of 10 μm obtained in UHV-deposited films are considerably less than the values predicted. Several possible causes of the difference between observed and predicted overgrowth are discussed.
A Model for Cw Laser Recrystallization Including Reflectivity Effects
Authors: Calder I.D. 
Published: March 2011

ABSTRACTA simple, practical model is developed for cw laser recrystallization of silicon and SOI structures, taking into account spatial variations in optical reflectivity. The power absorption is assumed to be uniform within each of three regions: the central molten spot, the annular two-phase region, and an outer annulus to account for absorption in the solid phase. Analytic expressions are obtained for the radial and depth dependence of the temperature, for the melt depth, the melt radius, the melt threshold, the crystallization threshold and the substrate melt threshold. SOI structures are considered and comparison with some experimental results shows excellent agreement.
Comparison of Soi Technologies
Authors: Wai Lam Hon 
Published: March 2011

ABSTRACTSilicon-on-Insulator (SOI) technologies are becoming more important as CMOS becomes the preferred technology for VLSI. The progress of the three most actively researched SOI technologies, beam-recrystallized SOI, implanted buried oxide and Full Isolation by Porous Oxidized Silicon will be summarized in this paper.
A Current Conduction Mechanism in Laser Recrystallized Silicon Metal-Oxide-Semiconductor Transistors
Authors: Lee Han-Sheng 
Published: March 2011

ABSTRACTN-channel MOS transistors were fabricated on silicon films that had been recrystallized by an argon ion laser at different power levels. These transistors showed electrical characteristics similar, but somewhat inferior to those devices fabricated on single crystal silicon substrates. These differences are attributed to the presence of trapping states at the grain boundaries of the crystallites in the recrystallized silicon. A coulombic scattering model is presented to explain these differences. In the case of films annealed at low laser power, an additional factor of nonuniform trap state distribution is invoked to explain device characteristics. This model provides an adequate explanation for the observed transport properties of transistors fabricated from recrystallized silicon films.
Two-Color Picosecond Measurements on Electron-Hole Plasmas Close to the Melting Phase Transition
Authors: Fauchet P.M. , Siegman A.E. 
Published: March 2011

ABSTRACTWe demonstrate a novel technique to study in detail the picosecond dynamics of semiconductors close to the melting phase transition. A variable-energy IR pulse (1.06 μm) is used to melt Si or GaAs samples via free carrierabsorption (FCA) in the dense and hot electron-hole plasma (EHP) produced by a preceding visible (532 nm) pulse. By varying the delay between the pulses and their relative intensities, we are able to verify the Lietoila-Gibbons model for pulsed laser heating, and to measure in detail important parameters of the EHP over a wide range of experimental conditions.
Pulsed Laser Annealing of Zirconia Capped, Native Oxides Free GaAs Surfaces
Authors: Pribat D. , Mercandalli L.M. , Croset M. , Siejka J. 
Published: March 2011

ABSTRACTWe have studied the effects of pulsed laser irradiation on silicon implanted, thermally activated , Calcia Stabilized Zirconia (CSZ) capped GaAs substrates. Reference substrates have also been irradiated in air for comparison. CSZ as a solid electrolyte has been used to chemically reduce the GaAs surface native oxides prior to irradiation while maintaining the surface stoechiometry. Our results indicate a spectacular decrease in defect density after laser irradiation of the CSZ capped-native oxide free samples, as compared to the samples irradiated in air.
Ir Radiation Transient Annealing of Silicon Implanted Si Gallium Arsenide
Authors: Ezis A. , Yeo Y. K. , Park Y. S. 
Published: March 2011

ABSTRACTThe electrical properties of IR radiation transient annealed Si implanted semi-insulating GaAs are presented for 100 keV ion doses from 3 × 1012 to 3 × 1014 cm−2. For wafers implanted with 3 × 1012 cm−2 doses, suitable for FET channel layers, carrier concentration and drift mobility profiles were determined from C-V and transconductance measurements on fat FET structures. Optimum electrical activation and carrier concentration profiles were obtained for peak pulse temperatures of 930–950°C. Van der Pauw measurements were made on substrates implanted with Si doses ≥ 1 × 1013 cm−2 to determine sheet carrier concentration and Hall mobility. The peak pulse temperature required to give optimum activation efficiency is found to increase with dose. The results presented here demonstrate that undoped substrates are preferable to Cr-doped substrates for low dose device applications.
Infrared Measurement of Carrier Density, Lattice Temperature and Melt Depth During Nanosecond Pulsed Laser Annealing of Silicon and Germanium
Authors: Preston J. S. , van Driel H. M. , Sipe J. E. 
Published: March 2011

ABSTRACTWe have performed infrared reflectivity measurements using 5.3 and 10.6μm probes to determine the plasma density, lattice temperature and melting kinetics of silicon and germanium following excitation by 25 nanosecond, 0.53 and 1. 06μm pulses. Below the threshold of melting, the maximum plasma densities are approximately 1020 cm−3; for both materials; these values and the spatial and temporal evolution of the plasma are consistent with well known generaticn, diffusion and recombination processes. Above the threshold for melting we have taken advantage of the large skin depth at infrared wavelengths to determine the melt front kinetics for depths up to 1000 Å using a contactless technique.
Liquid Phase Growth of Epitaxial Ni and Co Silicides by Pulsed Laser Irradiation
Authors: Tung R. T. , Gibson J. M. , Jacobson D. C. , Poate J. M. 
Published: March 2011

ABSTRACTEpitaxial Ni and Co silicides have been fabricated using pulsed laser melting. Interfacial instabilities and cell formation are suppressed during the liquid-phase epitaxy by melting mono or disilicide layers. Single crystal NiSi2 and CoSi2 films have been grown on (100) and (111) Si following a post-anneal. This method does not require UHV deposition or reaction techniques.
The Influence of Layer Structure on the Synthesis of AlSb by Laser Irradiation of Al/Sb Thin Film Couples
Authors: Baufay Luc , Pigeolet Andre , Andrew Rod 
Published: March 2011

ABSTRACTWe have previously described the formation of thin AlSb films by laser irradiation of sandwich-like structures of the components, and have shown that under quasi-adiabatic conditions, the transformation can be triggered by furnishing sufficient laser energy to just melt a part of the components; subsequent progressive liberation of the heat of formation of the compound drives the reaction to completion. In this paper, we clarify some details of the reaction and we investigate the influence of initial layer structure,thermal history, and total film thickness on the required laser threshold energy.
Ferrimagnetic Behavior and Magnetoresistance of Fe/Gd Double Structured Multilayer Films
Authors: Fujimori H. , Kamiguchi Y. , Hayakawa Y. , Takanashi K. 
Published: March 2011

AbstractWe prepared Fe/Gd double structured multilayer films (DSMLF's). The Fe/Gd DSMLF has a longer period λl, and it is composed of alternate stacking of two types of Fe/Gd submultilayers with a shorter period λs. One type of Fe/Gd submultilayers has dominant Fe layer magnetization, and the other, dominant Gd layer magnetization. λs was varied in the range from 12 to 100Å, keeping λl to about 250Å. The magnetization of Fe/Gd DSMLF's with λs≦36Å shows a spin-flop in magnetic fields lower than 1k0e at room temperature. The compensation temperature Tcomp was found to decrease with increasing λs. Tcomp crosses room temperature at λs=24Å, and then the spinflop field Hsf at room temperature takes a minimum value of the order of a few tens oersteds. Thus, we show that Hsf at room temperature can easily be tuned to a desired value by varying λs. Longitudinal (pl) and transverse (pt) magnetoresistances show a crossover, depending on the angle between directions of the electric current and of the Fe layer magnetization.
Cems Interface Study of (Fe/M)-Multilayers (M=Cr,Gd)
Authors: Sauer CH. , Landes J. , Zinn W. , Ebert H. 
Published: March 2011

AbstractThe temperature dependence of the magnetic hyperfine (hf.) fields near the interfaces in epitaxial Fe/Cr and partly epitaxial Fe/Gd bilayers were measured using 57Fe Conversion Electron Mössbauer Spectroscopy (CEMS). It was found that the Fe-Cr magnetic interaction extends only up to the second Fe-neighbor at the Fe/Cr interface, whereas the interaction range at the Fe/Gd interface is four times larger. For comparison the hf. fields and magnetic moments for Fe/Cr multilayers were obtained performing LMTO (Linear Muffin Tin Orbital) band structure calculations. The Néel temperature of a thin Cr-interlayer in a Fe/Cr/Fe sandwich structure was determined in dependence of the Cr-layer thickness.