bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elastic Properties and Structural Evolution of AgNi Superlattices
Authors: Rodmacq B. , Pelosin V. , Hillairet J. 
Published: March 2011

AbstractSilver-nickel multilayers were prepared by sputtering at 100 K. X-ray diffraction, electrical resistivity and dimensional variation measurements were performed to structurally characterize these stratified materials, both in the as-prepared state and during the course of annealing cycles. Clearly, polycrystalline superlattices with marked (111) texture perpendicular to the strata are formed. We studied the elastic properties of these superlattices by performing uniaxial tension tests. No deviation from linear elasticity was observed, whatever the period. Young's modulus was found to be 130±15 GPa for all the periods studied. Thus no significant functional dependence of Young's modulus on the stacking periodicity exists in the AgNi superlattice, in the range of periods explored, 2.6 to 18 nm.
Pulsed Laser Melting: The Effect of Implanted Solutes on the Resolidification Velocity
Authors: Galvin G. J. , Mayer J. W. , Peercy P. S. 
Published: March 2011

ABSTRACTTransient electrical conductance has been used to measure the resolidification velocity in silicon containing implanted solutes. Nonequilibrium segregation of the solutes occurs during the rapid resolidification following pulsed laser melting. The velocity of the liquid-solid interface is observed to depend on the type and concentration of the solute. A 25% reduction in solidification velocity is observed for an implanted indium concentration of three atomic percent. Implanted oxygen is also shown to reduce the solidification velocity. The dependence of the velocity on solute concentration impacts a variety of segregation, trapping and supersaturated solution studies.
Photoelectric Emission Studies from Crystalline Silicon at 266 Nm
Authors: Malvezzi A. M. , Liu J. M. , Bloembergen N. 
Published: March 2011

ABSTRACTThree different photoelectric regimes are observed in the interaction of 15 ps, 266 nm laser pulses with crystalline silicon samples versus light fluence. A superposition of linear and quadratic photoionization is followed by a space charge limited regime up to the critical fluence F4ωth for the surface amorphization where highly nonlinear ion emission is observed. Ion and electron emissions become equal in magnitude at a fluence - ∼ 2F4ωth The absence of observable thermionic effects indicates that thermal equilibrium of the electronhole plasma and the lattice is reached during the laser pulse duration.
Solidification of Highly Undercooled Silicon: Bulk Nucleation and Amorphous Phase Formation
Authors: Wood R. F. , Lowndes D. H. , Narayan J. 
Published: March 2011

ABSTRACTRecent experimental and theoretical work suggests that bulk nucleation occurs in highly undercooled liquid silicon formed by the pulsed laser melting of amorphous layers. In this paper we discuss the dynamics of solidification of undercooled liquid silicon in terms of results from melting model calculations and from the theory of homogeneous bulk nucleation. The relationship between the occurrence of bulk nucleation and the ability to induce a liquid-to-amorphous phase transition by large undercoolings of the liquid is considered. It is concluded that the observed liquid-toamorphous transition in silicon cannot be explained by an equilibrium thermodynamic approach.
Germanium Extremely Heavily Doped by Ion-Implantation and Laser Annealing: A Photoluminescence Study
Authors: Wagner J. , Contreras G. , Compaan A. , Cardona M. , Axmann A. 
Published: March 2011

ABSTRACTIt has been shown previously that dopant concentrations far above the equilibrium solubility limit can be obtained in semiconductors by pulsed laser annealing of heavily ion implanted material. We exploit this fact to study the photoluminescence of germanium with dopant concentrations up to 1021 cm−3. From this study we obtain information on the filling of higher lying band minima and the shift of the optical band gap as a function of carrier concentration over a much wider range than accessible with bulk doped material. In addition it is shown that photoluminescence provides a diagnostic tool to characterize implanted layers.
Concentration-Independent Solute Segregation in Laser Annealing of Semiconductor Crystals
Authors: Chikawa Jun-ichi , Sato Fumio , Sunada Tadasu 
Published: March 2011

ABSTRACTAtomic processes at the interface in regrowth following laser induced melting were investigated by observing behavior of impurity segregation. The interfacial segregation coefficient k* was obtained from depth profiles of solute atoms redistributed by laser irradiation of uniformly doped Si, Ge, and GayAl1−yAs crystals. It was found that k*=k0 for B in Si, Ga in Ge ih the growth rate range of 1 m/s. It is concluded that rapid growth freezes a state of liquid monolayer adjacent to the interface which has the character of ideal solution from dilute to eutectic composition for dopant-silicon systems and in the entire range of composition for the mixed crystal.
Relaxation Behavior of Metastable As and P Concentrations in Si After Pulsed and CW Laser Annealing
Authors: Goetzlich J. , Tsien P.H. , Ryssel H. 
Published: March 2011

ABSTRACTMetastable solid solutions of arsenic and phosphorus atoms were created by high-dose ion implantation in silicon, followed by annealing either with pulsed (Nd:YAG) or CW (CO2;) laser irradiation. The relaxation of these supersaturated layers was investigated by thermal post-treatment at temperatures between 600 and 1000°C. By measuring the time dependence of the sheet carrier concentration, the time constant and the activation energies for the relaxation of the electrically-active As and P atoms were investigated. In addition, the equilibrium carrier concentrations at different temperatures were obtained by Halleffect measurements in connection with a layer-removal technique.
Structural and Electrical Properties of Gas immersion Laser Doped Layers in Crystalline Silicon
Authors: Sigmon T.W. , Carey P.G. , Press R.L. , Fahlen T.S. , Pressley R.J. 
Published: March 2011

ABSTRACT4 He backscattering and channeling and 4-point probe resistivity measurements are used to characterize the doping of 〈100〉 Si directly from the gas phase by using a laser induced melt/recrystallization process. Impurity concentrations from 3×1019 to 5×1020 cm−3 and sheet resistivities as low as 20 Ω/╒ are obtained by variation of the laser energy density or number of passes. Diodes fabricated by this process exhibit near ideal I-V characteristics with sharp reverse breakdowns determined by junction edge effects. Annealing at 850° C further reduces the generation-recombination centers to values that result in an ideality factor of 1.0.
Rapid Annealing of Silicon
Authors: Hodgson R. T. , Deline V. , Mader S. M. , Morehead F. F. , Gelpey J. 
Published: March 2011

ABSTRACTSilicon implanted with arsenic or boron has been annealed with a 100kW argon arc lamp turned on for a few seconds until the wafer temperature was in the 850–1250°C temperature range. The differences in defect behavior between such rapid annealing and furnace annealing is pointed out, and the dopant diffusion is measured. Aside from an initial movement of the boron atoms left in interstitial positions after the implant, diffusion of the boron and arsenic is consistent with standard diffusion models.
Transient Annealing of Boron Implanted Devices
Authors: Wilson S. R. , Paulson W. M. , Varker C. J. , Lowe A. , Gregory R. B. , Reuss R. H. , Wu S. Y. , Whitfield J. D. 
Published: March 2011

ABSTRACTShallow-junction semiconductor devices have been fabricated using ion implantation and transient annealing with a Varian IA-200 isothermal annealer. Boron implanted diodes, npn bipolar transistors and CMOS ring oscillators have been fabricated and are compared to furnace annealed devices. Boron implanted diodes have been annealed with the RIA and yield acceptably low leakage currents, comparable to furnace annealed devices. The RIA devices have recombination lifetimes of ∼10 μsec. The bipolar transistors subjected to a transient anneal have good base-collector and emitterbase junctions as well as gains of ∼100 in good agreement with the design of the device. MOSFETs and CMOS ring oscillators were fabricated using self-aligned polysilicon gates. The transient annealed devices were equal or superior to devices which were furnace annealed at 800°C for 10 min. The low temperature furnace anneal was necessary to minimize short channel effects. The transient anneal resulted in ring oscillators which were a factor of two faster than furnace samples that were annealed.
Influence of Rapid Thermal Annealing on Shallow BF2 Implantation into Pre-Amorphized Silicon
Authors: Maszara W. , Carter C. , Sadana D. K. , Liu J. , Ozguz V. , Wortman J. , Rozgonyi G. A. 
Published: March 2011

ABSTRACTLow energy, shallow BF2+ implants were carried out at room or liquid nitrogen temperature into deep pre-amorphized (100) Si for better control of the dopant profile and post-annealing structural defects. Cross sectional and angle polished plan view transmission electron microscopy were used to study the structural quality of the implanted layer, while SIMS provided a chemical profile. Four types of structural defects were observed in BF2+ implanted, pre-amorphized samples following rapid thermal annealing with a halogen lamp. An in-situ ion beam annealing and the presence of F in the Si lattice were related to the creation of the defects. Good correlations between F gettering and TEM observed defects were found to exist. Implantation of B+ into a pre-amorphized Si surface and subsequent rapid thermal annealing was found to produce a wide defect-free surface layer.
Electron beam Annealing of Shallow BF2 Implantations
Authors: Jaussaud C. , Cartier A.M. , Escaron J. 
Published: March 2011

ABSTRACTA multiple scan electron beam system has been used to anneal silicon implanted with BF2 (25 Kev, 1, 2 and 5 × 1015 ions × cm−2 ). The annealing temperatures range from 1000 to 1200° C and the annealing times from 3 to 18 seconds. The curves of sheet resistance as a function of annealing time show a minimum. The increase in sheet resistance at longer annealing times is due to boron outdiffusion. Junction depths have been measured by spreading resistance and are presented. For implanted doses below 2 × 1015 ions × cm−2 boron outdiffusion limits the sheet resistance value at about 100 R Ωand this minimum value corresponds to an increase in junction depths of about 500 Å. For implanted doses of 5 × 1015 ions ×cm−2, 60 Ω sheet resistance can be obtained, but with about 1000 Å increase in junction depth.
CW Backside Laser Gettering
Authors: Hawkins Gilbert , Erikson George 
Published: March 2011

ABSTRACTA variety of backside damage techniques are available for gettering heavy-metal contaminants in silicon wafers. These include mechanical damage, ion implantation, thin film deposition, and pulsed–laser surface melting. In each case, strain fields and microscopic defects induced by the processing trap impurities as they diffuse through the wafer during subsequent high–temperature processing steps. We examine the defect structures produced by CW laser gettering, describe the dependence of gettering efficiency on wafer oxygen content and processing conditions, and demonstrate that CW laser processing can be an effective gettering technique even when the number of laser scan lines is reduced to make wafer processing acceptably rapid.
New Reliable Structure for High Temperature Measurement of Silicon Wafers Using a Specially Attached Thermocouple
Authors: Cohen S.A. , Sedgwick T.O. , Speidell J.L. 
Published: March 2011

ABSTRACTAccurate wafer temperature measurement is very important in the area of material processing. In Short Time Annealing, for example, it is necessary to monitor temperature peaks of up to 1200°C which are only a few seconds in duration. This paper describes a structure consisting of a silicon wafer with a specially attached thermocouple. This structure is capable of reliable high temperature measurements of up to 1200°C and is also capable of surviving repeated cycling at that temperature.
Rapid Thermal Annealing of Ion-Implanted Silicon and Gallium Arsenide
Authors: Narayan J. 
Published: March 2011

ABSTRACTWe have investigated the annealing of ion implantation damage (in the form of amorphous layers and/or the layers containing only dislocation loops) in silicon and gallium arsenide. The annealing of amorphous layers occurs by solid-phase-epitaxial growth and that of dislocation loops involves primarily loop-coalescence as a result of conservative climb and glide processes. The annealing of disolated loops occurs primarily by a bulk diffusion process. Almost a “complete” annealing of displacement damage is possible for shallow implants provided loop–coalescence does not lead to the formation of cross–grid of dislocations. For deep implants, the free surface cannot provide an effective sink for defects as in the case of shallow implants. Dopant profiles can be controlled to less than 1000 Å in layers having good electrical properties. The enhanced diffusion of dopants is observed probably due to entrapment of point defects in the annealed regions.
Electronic Defects in Silicon after Transient Isothermal Annealing
Authors: Pensl G. , Schulz M. , Stolz P. , Johnson N.M. , Gibbons J.F. , Hoyt J. 
Published: March 2011

ABSTRACTWe have investigated trap levels in silicon after Thermal Pulse Annealing (TPA). Three different annealing systems consisting of tungsten lamps or a graphite heater have been applied. Trap levels induced in different silicon materials (Cz, FZ, Epi) after TPA have been studied by DLTS and admittance spectroscopy. In boron-doped epitaxial silicon and As+- implanted pn-junctions (Cz grown Si), we have observed a prevalent trap level at concentrations of up to 1015cm−3 (depending on anneal conditions and silicon material). The ionization energy of this trap level is Ev+300meV.The concentration of the 300 meV-level was studied as a function of the annealing temperature and the quench rate. The thermal pre-processing history strongly affects the trap concentration induced by TPA. The 300 meV-level is almost completely removed by a subsequent furnace anneal at TA > 400°CFurther trap levels are created in boron- and aluminum- doped silicon by Ar+ or 30Si+ implantation and TPA. The defect natures are discussed.
Crystal Growth and Solute Trapping
Authors: Aziz Michael J. 
Published: March 2011

ABSTRACTA simple model for solute trapping during rapid solidification is presented in terms of a single unknown parameter, the interfacial diffusivity Di. A transition from equilibrium segregation to complete solute trapping occurs over roughly an order of magnitude in growth speed, as the interface speed surpasses the maximum speed with which solute atoms can diffuse across the interface to remain ahead of the growing crystal. This diffusive speed is given by Di/λ, where λ is the interatomic spacing, and is typically of the order 10 meters per second. Comparison is made with experiment. The steady–state speed of a planar interface is predicted by calculating the free energy dissipated by irreversible processes at the interface and equating it to the available driving free energy. A solute drag term and an intrinsic interfacial mobility term are included in the dissipation calculations. Steady–state solutions are presented for Bi–doped Si during pulsed laser annealing.
Kinetic Competition During Solid Phase Crystallization in Ion–Implanted Silicon
Authors: Olson G.L. , Roth J.A. , Hess L.D. , Narayan J. 
Published: March 2011

ABSTRACTWe report on an investigation of the temperature and concentration dependent kinetic competition between solid phase epitaxy and complex formation and precipitation in arsenic–implanted Si(100). Crystallization kinetics were monitored using time–resolved reflectivity during cw laser irradiation or furnace heating; microstructural changes were evaluated using cross–sectional TEM. At low temperatures and high As concentrations, complex formation and precipitation substantially alter the SPE kinetics. At higher temperatures competing interactions are less significant, and SPE becomes the dominant process. The kinetic competition between these processes is discussed with respect to the vacancy model for SPE.
Defect Reduction by Tilted Zone Crystallization of Patterned Silicon Films on Fused Silica
Authors: Fennell L. E. , Moyer M. D. , Biegelsen D. K. , Chiang A. , Johnson N. M. 
Published: March 2011

ABSTRACTIt is well known that crystal growth and defect propagation occur along the local thermal gradient at a liquid - solid interface, It is shown here that this property can be used to greatly reduce the density of structural defects in zone crystallized silicon thin films on amorphous substrates, A solidification front perpendicular to the direction of zone motion has its in - plane component of the thermal gradient parallel to the direction of zone motion. In this case, the defects, once nucleated, propagate along this zone path and the defect density reaches a steady state value. By using striped polysilicon patterning and a solidification front tilted relative to the molten zone path, a defect-free region is shown to occur. It is also shown that defects, once nucleated, are swept laterally from the region of interest and are terminated at the stripe boundary Methods of forming a tilted interface are proposed and demonstrated for CO2 laser crystallization.
Large Area Subgrain-Boundary-Free Sot Induced by Thermal Gradient Control of Transitional Seeded-Growth
Authors: Lee El-Hang 
Published: March 2011

ABSTRACTThe transitional region of subgrain-boundary-free crystal to subgrain-boundary-laced crystal formed during the initial stage of energy-beam induced seeded recrystallization of thin film silicon on an insulator has been examined to study the primary cause of subgrain boundary formation and the conceptual basis of its suppression. Observations include the systematic variation of: facet, cellular, and dendritic features; subgrain boundary directions and spacings; and the stable growth distance as a function of silicon film thickness and energy beam density. A temperature gradient argument based on constitutional supercooling theory has been used to explain these observations. There are indications that an increased thermal gradient at the solidification front can suppress the onset of growth instability for large area, defect free growth of SOI.
Two Dimensional Numerical Thermal Analysis of Silicon on Insulator Recrystallization Processes by a Moving Heat Source
Authors: Chang C.Y. , Fang Y.K. , Wu B.S. , Chen R.M. 
Published: March 2011

ABSTRACTThe moving-zone melt recrystallization of polysilicon on insulator substrate has been studied with computer simulation methods. The most important parameters such as upper strip heater moving velocity, the power of upper strip heater, substrate temperature were investigated. Generally speaking, temperature profile in multilayer and melt depth of poly-Si are difficult to be visualized, but are still important for recrystallization process. Therefore by using two dimensional finite difference method, a numerical analysis of moving melt zone recrystallization processes has been developed. Through this analysis, the temperature profile in multilayer and melt depth of poly-Si are depicted.
Fentosecond Time Resolved Surface Structural Dynamics of Optically Excited Silicon
Authors: Shank C. V. , Yen R. , Hirlimann C. 
Published: March 2011

ABSTRACTLaser processing of materials has raised a number of interesting issues relating to phase transitions and the structure of optically excited semiconductors. In this paper we describe the dynamics of structural changes that take place on a silicon surface following excitation with an intense optical pulse. Second harmonic generation from the silicon surface is used as a tool to measure crystalline order with 90 femtosecond resolution. The three-fold rotational symmetry of the silicon <111> surface is observed to become rotationally isotropic within a picosecond after excitation consistent with a transition from the crystalline to the liquid molten state.
Line-Source E-Beam Crystallization of Silicon-on-Insulator Films
Authors: Knapp J. A. , Picraux S. T. 
Published: March 2011

ABSTRACTSilicon-on-insulator films have been formed using a 20 mm by 1 mm line-source electron beam, with sample sweep speeds of 100–500 cm/sec and peak beam power densities up to 75 kW/cm2. Films were formed over 1 and 2 μm thick SiO2 isolating layers on 4°C diameter Si<100> wafers, with stripe openings of 5 to 100 μ width for seeding the crystallization from the substrate. Films consisted of Si layers from 0.4 to 1.0 μm thickness, with a capping layer of 2 μm SiO2. By sweeping the beam parallel to the long axis of the seed openings, smooth, oriented films were obtained, with low-angle grain boundaries confined to midway between seed openings. Best results were obtained for ≲ 50 μm spacing between seed openings.
Three-Dimensional Integrated Circuit Technology
Authors: Antoniadis Dimitri A. 
Published: March 2011

ABSTRACTWithin the last five years considerable research has focused on techniques to create “device-worthy” crystalline silicon films on insulators. Though several applications for such techniques have been proposed, none is more exciting than the prospect of “3-D Integration”, which has come to mean any IC technology that would yield more than one plane of active devices. This paper reviews the progress to date in this field by critically examining the merits and dismerits of the several silicon film preparation techniques, the several proposed 3-D device structures, and some possible applications of 3-D integration in electronic systems.
Laser Induced Synthesis of Compound Semiconductors
Authors: Laude L. D. 
Published: March 2011

ABSTRACTA review is given of a technique in which compound semiconductor films are produced by direct synthesis from multilayered, polymetallic films deposited onto insulating substrates and laser-irradiated in the CW or pulsed regime. Such films are characterized by a high degree of crystallinity together with optical and transport properties sufficiently close to single crystal ones to allow for various applications in optoelectronics.
Surface Temperatures and Dissociation Loss During the Pulsed Laser Annealing of GaAs
Authors: Pollock John T.A. , Rose Alex 
Published: March 2011

ABSTRACTFrom reported equilibrium partial and total dissociation pressure data for GaAs and melt times derived from reported time resolved reflectivity experiments, estimates have been made of the anticipated rate of As loss. Good agreement was found with experimentally determined As loss. A similar approach using experimentally determined Ga loss data allowed estimates of the maximum temperatures reached during pulsed laser annealing. These temperatures are considerably higher than suggested in thermal modelling studies. The boiling point of Ga gould be exceeded at incident laser energies >0.8 J cm−2.
Rapid Thermal Annealing of III–V Compound Materials
Authors: Kuzuhara M. , Kohzu H. , Takayama Y. 
Published: March 2011

ABSTRACTRapid thermal process utilizing radiation from halogen lamps has been used to post-anneal ion-implanted GaAs. Annealing conditions for Si implants in GaAs are discussed from the view point of applying this technique to GaAs MESFET fabrication. Also, the properties of S and Mg implants in GaAs followed by rapid thermal annealing are comparatively studied with the results after conventional furnace annealing. High electrical activation and minimized implant diffusion for both low and high dose implants are the principal features of this technique. The fabricated MESFET showed much higher transconductance without any anomalous characteristics, indicating this technique to be a promising alternative to conventional furnace annealing.