bluuebunny/crossref_metadata_2025_split huggingface dataset:
Raman Studies of Phase Transformations In Pulse Laser Irradiated Dielectric Films
Authors: Exarhos Gregory J. 
Published: March 2011

ABSTRACTSputter deposited TiO2 and ZrO2 films on silica have been characterized with regard to thickness, phase purity, and residual film stress using nondestructive Raman spectroscopic techniques. Irradiated anatase coatings exhibit vibrational features that irreversibly shift to higher frequencies, suggesting an increase in localized stress. Catastrophic damage is manifested by the appearance of a higher density rutile phase. Rutile coatings examined after irradiation show only intensity changes, while amorphous coatings were found to rapidly crystallize under high-pulse energy irradiation. Results of these studies are compared with equilibrium Raman measurements of thermally-induced transformations in these materials.
Observation of Superheating During Picosecond Laser Melting ?
Authors: Fabricius N. , Hermes P. , Linde D. Von Der , Pospieszczyk A. , Stritzker B. 
Published: March 2011

ABSTRACTThe surface temperature of GaAs during pulsed laser heating is obtained from the measured velocity distributions of evaporated atoms. For nanosecond pulses the observed solid-liquid transition temperature agrees with the equilibrium melting point TM. With picosecond pulses the temperature rises above TM by several hundred degrees before melting can be detected. This result is interpreted as evidence of superheating.
Picosecond Transient Reflectance Measurements of Crystallization In Pure Metals
Authors: MacDonald C.A. , Malvezzi A.M. , Spaepen F. 
Published: March 2011

ABSTRACTThe kinetics of rapid crystallization in metals is investigated by measuring transient optical property changes in laser irradiated gold and copper films in the picosecond and nanosecond regimes. Melt thresholds are determined by examining concentration profiles of multi-layered films before and after irradiation.
Time-Resolved Laser Induced Transformations In Crystalline Te Thin Films
Authors: Marinero E. E. , Pamler W. , Chen M. 
Published: March 2011

ABSTRACTWe report on time-resolved measurements of laser-induced transformations in Te thin films. Rapid thermal transformations are effected utilizing a KrF excimer laser (12 ns duration, 249 nm). The kinetics of the transformation is investigated utilizing transient conductance and infrared absorption measurements as well as reflectivity and transmissivity changes at 633 nm. The threshold for melting is accurately determined as well as melt velocities pertinent to the recrystallization kinetics of the molten films. Criteria for glass formation of Te are also discussed.
Pulsed Laser Interactions With Condensed Matter
Authors: Bloembergen N. 
Published: March 2011

ABSTRACTThe primary interaction is the absorption of photons by electrons. In metals free-free transitions increase the energy of the electron gas. In semiconductors and insulators electron-hole pairs are created, if the photon energy exceeds the band gap. If it is less, only multiphoton processes can initiate energy transfer from the light beam. In nearly all solid materials Auger processes and electron-phonon interactions occur on a picosecond time scale for the high density and energy of the carrier gas created by intense short laser pulses. Thus melting and evaporation of the material can occur on this time scale. These processes may be considered as the initial phases in the creation of laser produced plasmas. They have been studied by time-resolved measurements of the complex index of refraction, by electron and ion emission, by second harmonic generation, by electrical conductivity and other techniques. Fast time resolution is essential. The dynamic behavior of atoms and phase transitions in the picosecond and femtosecond regime has been opened up for experimental investigation.
Enhancement of Grain Growth In Ultra-Thin Germanium Films By Ion Bombardment
Authors: Atwater Harry A. , Smith Henry I. , Thompson Carl V. 
Published: March 2011

ABSTRACTWe report the enhancement of grain growth in 50 nm-thick Ge films during Ge ion bombardment, or self-implantation, at 500-600 ° C. Conventional and cross-sectional transmission electron microscopy (TEM) indicate that normal grains grow to a columnar structure at considerably lower temperatures than during ordinary thermal annealing. Furthermore, self-implantation-enhanced normal grain growth is found to be very weakly dependent on temperature. The time dependence and temperature dependence of grain growth during self-implantation were compared with data for thermal annealing experiments and suggest that the enhancement results from elastic collisions between ions and atoms located at the grain boundaries.
Impurity Diffusion, Crystallization And Phase Separation In Amorphous Silicon.
Authors: Elliman R.G. , Poate J.M. , Williams J.S. , Gibson J.M. , Jacobson D.C. , Sood D.K. 
Published: March 2011

ABSTRACTDiffusion, crystallization and phase separation processes in indium implanted amorphous silicon are examined for low temperature annealing (600°C). Both diffusion and crystallization are shown to be extremely sensitive to the indium concentration. Diffusion coefficients more than 10 orders of magnitude higher than tracer diffusion coefficients in crystalline silicon are measured, and amorphous to crystalline silicon transitions at temperatures as low as 350°C are reported. Phase separation is also observed.
Phase Transformations In Nickel-Aluminum Alloys During Ion Beam Mixing
Authors: Eridon James , Rehn Lynn , Was Gary 
Published: March 2011

ABSTRACTThe effect of ion beam mixing of nickel-aluminum alloys with 500 keV krypton ions has been investigated over a range of temperature, composition, ion dose, and post-irradiation thermal treatments. Samples were formed by aternate evaporation of layers of aluminum and nickel. A portion of these samples was subsequently annealed to form intermetallic compunds. Irradiations were performed at both room temperature and 80 K using the 2 MV ion accelerator at Argonne National Laboratory. Phase transformations were observed during both in situ irradiations in the High Voltage Electron Microscope(HVEM) at Argonne and also in subsequent analysis of an array of irradiated samples. Electron diffraction indicates the presence of metastable crystalline structures not present in the conventional nickel-aluminum phase diagram. Transformations occur at doses as low as 5×1014 cm−2 and continue to develop as the irradiation progresses up to 2×l016 cm−2. Layer mixing is followed through Rutherford Backscattering analysis. Samples are also checked with x-rays and Electron Energy Loss Spectroscopy (EELS). A thermodynamic argument is presented to explain the phase transformations in terms of movements on a free energy diagram. This analysis explains the interesting paradox concerning the radiation hardness of the NiAl[l] phase and the amorphous structure of mixed Ni-50% Al layers[2].
Electron Ream-Induced Phase Transformation In MgA1204SPINEL
Authors: Shaibani S.J. , Buckley S.N. 
Published: March 2011

ABSTRACTBombardino stoichiometric MgAl204spinel at elevated temperatures with hiqh energy electron beams ciradually converts the irradiated area into γ-alumina. This phase transformation, which involves the diffusion of maginesium out of the irradiated area, shrinks the oxygen ion sublattice, thereby generating internal stresses which cause localised crystal fractures.Three categories of crack are observed:type 1, the majority, are straiciht and lie at the centre of the irradiated area; type 3 are circular and they are located near the edge of the irradiated area in the spinel matrix: and, type 2 are hybrids. A quantitative model which explains the development of all types of crack is presented.The proportion of γ-alumina produced, the fractional loss of magnesium and the extent of crackino are found to depend on the electron beam energy, the electron dose, the beam profile and the irradiation temperature.
Rapid Thermal Annealing of B or N Implanted Monocrystalline 1-SiC Thin Films and its Effect on Electrical Properties and Device Performance
Authors: Ryu Jae , Kim H. J. , Davis R. F. 
Published: March 2011

ABSTRACTThe annealing behavior of B or N dual implants in 1-SiC thin films has been studied using cross-sectional transmission electron microscopy (XTEM), secondary ion mass spectroscopy (SIMS), and four point probe electrical measurements. A high resistivity layer was produced after annealing the B implanted-amorphous layer in the temperature range from 1000°C to 1500°C for 300 a; however, the resistivity rapidly decreased as a result of annealing at higher temperatures. The reasons for these changes in resistivity and the lack of p-type conduction at all annealing temperatures in these B implants include: (1) possible compensation of the native n-type carriers, (2) reduction in the B concentration via formation of B-containing precipitates between 1300°C and 1600°C and out diffusion of this species at and above 1600°C, and (3) creation of additional n-type carriers.No precipitates or defect structure was observed in N implanted-annealed samples. The resistivity of this non amorphous n-type layer decreased with increasing annealing temperatures from 700°C to 1800°C. Furthermore n-p junction diodes were fabricated for the first time in β-SiC via N implantation into samples previously in situ doped with 8 × 1018/cm3 Al coupled with rapid thermal annealing at 1200°C for 300 a. A typical diode ideality constant and a saturation current for these diodes was 3.4 and 9 × 10-10 A/cm2, respectively.
Temperature Measurement and Control in a Rapid Thermal Processor
Authors: Sheets Ronald E. 
Published: March 2011

ABSTRACTRapid Thermal Processing (RTP) of silicon or other semiconductor materials requires accurate measurement and control of temperature. In a typical RTP cycle, heating of the wafer takes place in seconds, making accurate control of the wafer temperature very critical. Non contact wafer temperature sensing is achieved using an optical pyrometer. Precise temperature control from 400° C to 1350° C is maintained with a closed loop control system consisting of an optical pyrometer and a computer. Sources of errors due to variations in emissivity as a function of wafer temperature, surface conditions and background radiation are discussed. Calibration of the system is achieved by using a thermocouple instrumented wafer.
Rapid Thermal Anneaung of Arsenic-Phosphorus(N+-N-) Double-Diffused Shallow Junctions
Authors: Kwong D. L. , Alvi N. S. , Ku Y. H. , Cheung A. W. 
Published: March 2011

ABSTRACTDouble-diffused shallow junctions have been formed by ion implantation of both phosphorus and arsenic ions into silicon substrates and rapid thermal annealing. Experimental results on defect removal, impurity activation and redistribution, effects of Si preamorphization, and electrical characteristics of Ti-silicided junctions are presented.
Silicides and Rapid Thermal Annealing
Authors: d'Heurle F. M. , Hodgson R. T. , Ting C. Y. 
Published: March 2011

ABSTRACTIn the first part of this paper the role of rapid thermal annealing in sulicide processing is viewed from a theoretical point of view with respect to what is known about metal-silicon reactions. The second part is a brief survey of the quickly expanding literature on the rapid thermal annealing of silicides. Whereas RTA does not appear to solve all, or perhaps even any, of the problems encountered in the use of silicides, it is concluded that RTA presents a number of definite advantages.
Limited Reaction Processing of Silicon: Oxidation and Epitaxy
Authors: Gronet C. M. , Sturm J. C. , Williams K. E. , Gibbons J. F. 
Published: March 2011

ABSTRACTLimited reaction processing has been used to grow thin, high quality layers of epitaxial silicon, silicon dioxide, and polycrystalline silicon. Multiple layers of these materials were deposited in – situ to demonstrate control of layer thicknesses, interface transition regions, and interface cleanliness. MOS and p-n junction structures were fabricated which exhibit electrical characteristics comparable to those of devices produced by conventional techniques.
A Study of Se+ Implants into Encapsulated GaAs
Authors: Gwilliam R. , Shahid M. A. , Sealy B. J. 
Published: March 2011

ABSTRACTThe effects of implanting Se+ ions through Si N4 layers have been compared with implants into uncapped GaAs. Through nitride implants have a higher residual damage, lower carrier concentration and lower mobility following rapid thermal annealing between 850 and 975 °C. The effect is believed to be due to the interface strain between the encapsulant and the amorphous GaAs.
Rapid Thermal Annealing of Be Implanted in 0.53Ga 0.47As
Authors: Lam Christine S. , Fonstad Clifton G. 
Published: March 2011

ABSTRACTRapid thermal annealing (RTA) techniques have been developed to activate shallow, high dose implants in InGaAs. Activation of deep, multiple energy high dose beryllium implants was also investigated. Two-step RTA cycles which peaked at a high temperature momentarily and then held at a lower temperature for 3 to 10 seconds were used to activate the implanted dopants. Over 80% activation was achieved. The results are superior to furnace anneal results, and at least comparable to graphite strip heater results. Increasing the anneal temperature on higher dose implants, however, type conversion was observed when the peak temperature exceeded a certain value.
Multi-Step Rapid Thermal Annealing of Si-Implanted Gaas for Microwave Discrete Devices and Monolithic Integrated Circuits Fabrication
Authors: Yu Tan-Hua , Kong W. M. , Lester L. F. , Smith P. M. , Duh K. H. G. , Hwang J. C. M. 
Published: March 2011

ABSTRACTIn this paper, we report a multi-step rapid thermal annealing process for microwave discrete devices and monolithic integrated circuits fabrication. 2” diameter undoped liquid encapsulated Czochralski GaAs wafers were implanted with 29 Si+ and annealed without capping using incoherent light from high intensity halogen lamps. The annealing was carried out in multiple temperature steps to achieve optimum damage removal and dopant activation. As a result, wafers implanted with mid 1012 cm−2 dose exhibited 85–90% activation efficiency for 100kV implant and nearly 100% activation for 300 kV implant. In comparison with single-stepannealed wafers, multi-step-annealed wafers showed not only higher activation efficiency, but also more uniform activation, higher electron mobility and better device performance.
Zone Melting Recrystallization of GaAs Films on Oxidized Si
Authors: Zhu Weiwen , Wang Weiyuan 
Published: March 2011

ABSTRACTIn this paper, GaAs SOI consisting of MBE deposited GaAs films on oxidized Si was recrystallized by narrow-zone melting in a RF induction graphite strip heater at a rate of 1–1.2 mm/s. The original grain size of MBE GaAs SOI films is smaller than 800 Å, and the electron diffraction patterns appear as typical polycrystalline rings as determined by SEM and ED, respectively. After zone melting recrystallization, the grain size of GaAs SOI films increases to 1 µm, the prefered ˂111˃ diffraction spots appear apparently, and the carrier concentrations and electron mobility amount to 3×1017cm−3 and 1.1×103cm2/v.s as determined by Hall measurement. The AES Ga/As signal ratio of the GaAs SO before and after recrystallization is the same as that of the GaAs single crystal. The possible application of GaAs SOI to devices is discussed.
Formation of Epitaxial Soi Structures Using Alkaline Earth Fltuoride Films
Authors: Ishiwara Hiroshi , Asano Tanemasa 
Published: March 2011

ABSTRACTRecent progress in the research of heteroepitaxial SOI structures such as Si/CaF2/Si and Ge/CaF2/Si structures is reviewed. Structural and electrical properties of alkaline earth fluoride films on Si substrates are first discussed. Growth conditions, structural properties, and device applications of the Si/CaF2/Si structures are then presented. It is shown that a predeposition technique, in which a thin Si layer is deposited at room temperature prior to the growth of a thick film at elevated temperature, is effective to improve the crystalline quality and the surface morphology of the film. Usefulness of solid phase epitaxy to obtain high quality films is also demonstrated. Finally, it is shown that the predeposition technique is also useful in formation of Ge/CaF2/Si structures.
Comparison of Structural and Electrical Characteristics of Solid-Phase Epitaxial Films Recrystallized By Rapid Thermal Annealing and Furnace Annealing
Authors: Sundaresan R. , Chang P.-H. , Malhi S.D.S. , Lam H.W. 
Published: March 2011

ABSTRACTSolid-phase epitaxial regrowth of polysilicon films. amorphized by a room-temperature silicon implant. has been achieved using a (low temperature) furnace anneal or a (high temperature) rapid thermal anneal. Lateral extension of the growth onto an oxide layer, 4 μm wide, has also been observed. The electrical properties of the films were examined by building MO2S devices in them. Average electron mobilities of 520 cm2/v-sec and 200 cm2/v-sec have been measured for films regrown on top of silicon and oxide respectively.
Epitaxial Regrowth of a-GaAs/(100) Silicon By Excimer Laser Annealing at 248 nm
Authors: Christou A. , Efthimiopoulos T. , Kyriakidis G. , Varmazis C. 
Published: March 2011

ABSTRACTExcimer laser annealing at 248 nm has resulted in the recrystallization of a-GaAs on (100) silicon. An AlAs encapsulation layer was found to be necessary to prevent the loss of arsenic during laser annealing. An energy density of 105 mJ/cm2 was the critical energy density which gave optimum results. Field effect transistors were fabricated on the regrown (100) GaAs utilizing ion implantation for the n-type channel, and resulted in a transconductance of 70–80 mS/mm.
Formation of Facets at the Solid-Melt Interface in Silicon
Authors: Arnold Emil , Landman Uzi , Ramesh S. , Luedtke W. D. , Barnett R. N. , Cleveland C. L. , Martinez A. , Baumgart H. , Khan B. 
Published: March 2011

ABSTRACTWe have done experimental and theoretical studies of the origins of facet formation at the solid-liquid interface in laser-beam-melted silicon films. Two laser beams were used to produce a molten zone with a closely controlled thermal profile in a thin single-crystal film of silicon, and the liquid-solid interface was observed in situ. A transition to a faceted structure was found to occur under conditions of near thermal equilibrium. The solidliquid interface was also studied theoretically by means of molecular dynamics simulations, incorporating pair- and three-body terms in the interaction potential. Similarly to the experimental system, the solid-melt interface in the simulated system breaks up into facets defined by (111) planes. The melt region in the vicinity of the faceted planes exhibits a certain degree of ordering due to the influence of the crystalline potential.
Formation of Buried Sio2 By High Dose Implantation of Oxygen at Room and Liquid Nitroeen Temperatures
Authors: Namavar F. , Budnick J. I. , Sanchez F. H. , Hayden H. C. 
Published: March 2011

ABSTRACTWe have carried out a study to understand the mechanisms involved in the formation of buried SIO2 by high dose implantation of oxygen into Si targets. Oxygen ions were implanted at 150 keV with doses up to 2.5 X 1018 ions/cm2 and a current density of less than 10 μA/cm2 into Si 〈100〉 at room and liquid nitrogen temperatures. In-situ Rutherford backscattering (RBS) analysis clearly indicates the formation of uniform buried SIO2 for both room and liquid nitrogen temperatures for doses above 1.5 X 1018/cm2.Oxygen ions were implanted at room temperature into crystalline quartz to doses of about 1018 ions cm2 at 150 keV, with a current density of 〈10〉10 μA/cm2. The RBS spectra of the oxygen implanted quartz cannot be distinguished from those of unimplanted ones. Furthermore, Si ions were implanted into crystalline quartz at 80 keV and dose of 1 X 1017 Si/cm2, and a current aensity of about 1 μA/cm2. However, no signal from Si in excess of the SiO2 ratio could be observed. Our results obtained by RBS show that implantation of either Si+ or O into SiO2 under conditions stated above does not create a layer whose Si:O ratio differs measurably from that of SiO2.
Donor Creation During Oxygen Implanted Buried Oxide Formation
Authors: Delfino M. , Chu P.K. 
Published: March 2011

ABSTRACTEnhanced electron conductivity is observed in silicon that has been implanted with oxygen ions to form a buried oxide layer. The conductivity is attributed to donors that are created in the silicon both above and below the oxide. Secondary ion mass spectrometry and Rutherford backscattering spectroscopy show that, during subsequent annealing, oxygen accumulates only in the silicon surface. This causes the donors in the silicon surface to be easily activated to high concentrations and, unlike donors beneath the oxide, to be extremely resistant to thermal annihilation.
Reduced Subboundary Misalignment in SOI Films Scanned at Low Velocities
Authors: Pfeiffer Loren , West K. W. , Joy D. C. , Gibson J. M. , Gelman A. E. 
Published: March 2011

ABSTRACTSilicon-on-Insulator (SOI) films on SiO2 scan-melted at low velocities (20 to 300 µm/sec) with reduced thermal gradients at the melt-freezing interface are found to have qualitatively different properties from similar films melt-scanned at higher gradients and scan velocities. The transition between the two regimes appears to be abrupt. Scanning at intermediate velocities often results an admixture of patches containing one or the other type of material. The slow scan regime is characterized by long straight non-branched subboundaries having a lateral spacing 50-60 µm, and very small tilt misalignments of 0.1° or less. These slow scan subboundaries are found to consist largely of threading dislocations in contrast conventional subboundaries which are tilt boundaries of up to 3° and typically consist of edge dislocations running in the plane of the film.
Photoconduction in Thin-Film Transistors Fabricated from Lasercrystallized Silicon on Fused Quartz
Authors: Chiang A. , Zarzycki M. H. , Johnson N. M. 
Published: March 2011

ABSTRACTPhotoconduction with optical gain in excess of 3000 is achieved in depletion-mode MOSFETs fabricated from laser-crystallized silicon thin-films on fused quartz. Devices operated with a reverse gate bias show responsivity of ≥ 300 Amp/Watt for radiation in the visible spectrum and dynamic range of > 106. This process occurs by spatial separation of photogenerated electron-hole pairs across a p-n junction in the device body, collection of holes in the floating substrate, and conduction of electrons in a buried channel in the bulk of the nearly defect-free silicon film. This study explores the influence of channel dopant profile on the photoconduction process and the latitude for optimized photodetector performance. The effect of post-crystallization residual structural defects on performance uniformity is also evaluated.
A Method to Determine the Density of Surface States and Interfacial Charge Density in N-Channel Sos Mosfet's
Authors: Annamalai N.K. , Khondker A.N. 
Published: March 2011

ABSTRACTA method to determine the density of surface states NSS and interfacial charge density QSAP in n-channel silicon-on-sapphire MOS transistors from back channel leakage current measurements is presented. A rigorous theory to determine this current as a function of drain-to-source bias, VDS and as a function of body-to-source bias, VBS is also discussed. The evaluation of leakage current is more rigorous in this work because the surface potential is explicitly calculated from the charge neutrality equation of the device. The surface potential, being dependent on interfacial surface state density and the doping density, is more accurate when evaluated from the charge neutrality equation than from assuming a simple a priori value (ɸs={3/2}ɸF). Applying the present theory to experimentally reported leakage current values, the following were obtained: