bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polypropylene Fibre Reinforced Concrete Air Permeability
Authors: Sanjuan Miguel A. , Moragues A. , Bacle B. , Andrade C. 
Published: March 2011

AbstractThe permeability of concrete to gases is of direct importance to the durability of concrete structures, because of carbon dioxide flowing through the concrete favour lime carbonation and reinforcing steel corrosion.Mortar with and without polypropylene fibres having water/cementitious ratios of 0.30, 0.35 and 0.40 and a cement/sand ratio of 1/1 were studied. Polypropylene dosage varied from 0.1 to 0.3% by volume of cement.The characterization of mortar permeability was made using cylindrical shaped samples (3 cm height and 15 cm diameter). These specimens were 28 days cured and then dried before the test.The addition of fibres results in a decrease of air permeability. Variation of the water/cement ratio is of lesser importance than fiber addition.
Is There a Way to a Perfect Rapid Thermal Processing System?
Authors: Kakoschke R. 
Published: March 2011

AbstractThe temperature within a rapid thermal processing system is characterized by the intensity distributions of the lamp light and of the reabsorbed heat radiation of the wafer. The intensity to the front and back side of the wafer and to the wafer edge have to be considered for pattern induced effects and additional energy loss at the edge, respectively. Monte-Carlo simulations show that the major problems with a multi lamp arrangement with surrounding reflector are due to nonuniform irradiation by the lamps, nonuniform energy loss of the wafer, and additional energy loss at the wafer edge. The temperature influencing quantities cannot be optimized at the same time without modifications of the reflector geometry or without a subsidiary light flux which is controllable independently of the lamp light.
Improvement of Temperature Uniformity in Rapid Thermal Processing Systems Using Multivariable Control
Authors: Norman S. A. , Schaper C. D. , Boyd S. P. 
Published: March 2011

AbstractDuring rapid thermal processing (RTP) of a semiconductor wafer, maintenance of nearuniform wafer temperature distribution is necessary. This paper addresses the problem of insuring temperature uniformity in a cylindrical RTP system with multiple concentric circular lamps.A numerical technique is presented for optimizing steady-state temperature distribution by independently varying the power radiated by each lamp. It is shown for a simulated system, over a wide range of temperature setpoints, that the temperature uniformity achievable with multivariable (“multiple knob”) control of lamp powers is significantly better than that achievable with scalar (“single knob”) control.The difficulties of using scalar control in RTP are more severe in the case of temperature trajectory design than in the case of steady-state temperature maintenance. For example, with scalar control the rate of temperature increase during ramping is limited because temperature nonuniformity can cause slip defects in the wafer. A numerical technique is presented for designing multivariable lamp power trajectories to obtain near-optimal temperature uniformity while wafer temperature tracks a specified ramp, resulting in slip-free ramp rates much faster than those achievable with scalar control.
Temperature Control and Temperature Uniformity During Rapid Thermal Processing
Authors: Vandenabeele Peter , Maex Karen 
Published: March 2011

AbstractAn overview is given of the major problems in temperature control and uniformity control. For temperature control varying emissivity due to layers, roughness, doping and chamber design are discussed, together with problems due to lamp radiation. The main way to go seems to be in-situ emissivity correction. For uniformity control, the main problems are non-uniform reflector radiation and patteren induced non-uniformity. The solution seems to be the design of a reflective chamber with uniform reflected radiation.
Thermal Effects of Gasses in Rapid Thermal Processing
Authors: Knutson K. L. , Campbell S. A. , Leighton J. D. 
Published: March 2011

AbstractA numerical model has been created for a Rapid Thermal Processing (RTP) system. Experiments have been done to show the validity of the model. The simulations done examine thermal uniformity and stresses incurred by RTP during steady state operation and during short time temperature ramps. It is shown that increasing the radiant intensity at the edge of the wafer reduces stress, compared to a uniform radiant field, in steadystate operation but increases stress during short time temperature ramps.
Rapid Thermal Chemical Vapor Deposition of Germanium and Germanium/Silicon Alloys on Silicon: New Applications in the Fabrication of MOS Transistors
Authors: Öztürk M. C. , Grider D. T. , Ashburn S. P. , Sanganeria M. , Wortman J. J. 
Published: March 2011

AbstractIn this work, low pressure chemical vapor deposition (LPCVD) of pure Ge and SixGe1-x on Si and SiO2 has been considered for new applications in future ultra large scale integration (ULSI) technologies. Depositions were performed in a lamp heated cold-wall rapid thermal processor (rapid thermal chemical vapor deposition -RTCVD) using thermal decomposition of GeH4 and SiH2Cl2 in a carrier gas of H2. It is shown that RTCVD of Ge on Si is highly selective with no deposition occuring on SiO2. The selectivity of Ge/Si depends on the amount of germane in the gas phase. The processes are relatively low temperature/high throughput processes suitable to single wafer manufacturing. In this paper, we review potential applications of Ge and SixGe1−x in future MOS processes. Specifically, Ge and SixGe1−x have been considered for three new applications: i) fabrication of raised source/drain structures where selective Ge or SixGe1−x is used as a sacrificial layer to eliminate silicon consumption during silicide formation (by forming a germanide), ii) Formation of ultra-shallow junctions in silicon using selectively deposited and implanted polycrystalline SixGe1−x as a diffusion source, iii) Formation of MOS gate structures with SixGe1−x gate electrodes for lower dopant activation temperatures and better threshold control.
Low Temperature Epitaxial Silicon Growth in a Rapid Thermal Processor
Authors: McNeill D. W. , Gamble H. S. , Armstrong B. M. 
Published: March 2011

AbstractA rapid thermal processor has been used for the study of epitaxial silicon growth. Without the need for UHV conditions, bulk contamination levels of oxygen and carbon have been reduced to 5E17 cm−3, at a growth temperature of 750°C. In-situ cleans have been assessed as substrate preparation techniques. High temperature H cleans can reduce interfacial doses of both oxygen and carbon to below 5E13 cm−2. I-owever, low temperature cleaning, using a remote fluorine-based plasma, has as yet only achieved oxygen and carbon doses of 5E14 cm−2 and 3E15 cm−2 respectively. Minority carrier lifetimes of a few micro seconds and electron carrier concentrations of about 1E15 cm−3 are typical for undoped films grown at 750°C. In-situ doping with phosphine has also been employed. Typical doping levels of 5E19 cm−3 uniformly distributed throughout the layers have been achieved. The phosphorus is electrically active in the as-grown film with typical carrier mobility estimated to be 104 cm2v−1s−1.
Growth of Epitaxial Silicon Carbide on Silicon by Rapid Thermal LPCVD
Authors: Ruddell F.H. , Armstrong B.M. , Gamble H.S. 
Published: March 2011

AbstractThis paper describes the growth of epitaxially aligned SiC on < 111 > and < 100 > silicon substrates at 970°C, using rapid thermal LPCVD. A growth mechanism comprising carbonation of silane adspecies has been deduced.
A New Recrystallization Technique for Large Area Thin Film Silicon on Glass Structure
Authors: Hayama Hiroshi , Mukainari Masahito , Saito Takeshi 
Published: March 2011

AbstractA new recrystallization technique has been proposed, with which a large area thin film silicon on glass structure is able to be recrystallized. The technique utilizes self-heat-confinement caused by induction eddy currents, analogous to floating zone crystal refining technique. An experimental recrystallization system is shown. A recrystallized silicon layer with some hundred micron grain size was obtained with the system.
Activation of Sb in Ultra-Shallow Poly-Silicon Emitters Using Rapid Thermal Processing.
Authors: Grelsson Ö. , Söderbärg A. , Magnusson U. , Olsson J. , Mohadjeri B. 
Published: March 2011

AbstractAn ultra-shallow poly-silicon emitter formed by different heat treatments including RTA of an evaporated, antimony doped, poly-silicon structure is presented. The fabrication process together with electrical characterizations, resistivity measurements and SIMS analysis are given. Especially, the impact of RTA treatment on the electrical characteristics of these emitter structures is investigated. Also, the IV and Gummel characteristics of a bipolar transistor with this type of poly-silicon emitter is given.
Lateral Uniformity of Ultra-Shallow Junctions Formed by Rapid Thermal Annealing in Polysilicon-on-Silicon Systems
Authors: Batra S. , Park K. , Banerjee S. , Smith T. , Mulvaney B. 
Published: March 2011

AbstractLateral non-uniformities can be expected in the dopant diffusion front in the substrate in polysilicon-on-single crystal Si systems upon Rapid Thermal Annealing (RTA), because the grain boundaries in polysilicon act as fast diffusant pipelines and also possibly inject defects into the substrate, which can locally enhance diffusivities in the substrate due to dopant-point defect interactions. The lateral uniformity of As, B and P ultra-shallow junctions formed in the substrate by indiffusion from as-deposited amorphous or polysilicon films has been studied using concentration dependent etching and transmission electron microscopy. Due to a larger final grain size after annealing in the case of as-deposited amorphous Si films compared to asdeposited polysilicon films, there is significant lateral doping inhomogeneities in the diffusion front. However, the doping inhomogeneities are gradually smeared out as the impurities diffuse deeper into the substrate due to lateral as well as vertical diffusion.
In-Situ Temperature Estimation in Rapid Thermal Processing Systems using Extended Kalman Filtering
Authors: Cho Y.M. , Schaper C.D. , Kailath T. 
Published: March 2011

AbstractAn Extended Kalman Filter (EKF) is developed to provide an improved pyrometer-based estimate of temperature in rapid thermal processing systems. Models of the heat transfer characteristics, emissivity variations, and temperature measurement equipment, are used in formulating an EKF as a closed-loop observer to filter out noise, lessen the effects of processing variations, and to infer temperature at locations where no measurements are available. Extensive simulations are conducted to analyze the robustness of the EKF.
Synchrotron X-Ray Topography as a Non-Destructive Monitor of Damage Accompanying IC Processing
Authors: Dudley Michael , Wang Franklyn F.Y. , Fanning Thomas , Gordon-Smith David 
Published: March 2011

AbstractSynchrotron white beam x-ray topography in transmission geometry has been used to monitor the damage accompanying a Rapid Thermal Processing (RTP) treatment of Si wafers. The behavior of low and high carbon-content Si is contrasted and discussed. The applicability of this technique to this kind of study is demonstrated, with particular emphasis being laid on its non-destructive nature. The general usefulness of the technique as a monitor for damage accompanying IC processing is discussed.
Investigation of Metal Induced Surface Defects in Czochralski Si Following Rapid Thermal Processing by Thermal Wave Modulated Reflectance Method
Authors: Hahn S. , Smith W.L , Suga H. , Park J.-G. , Lim C.-S. , Kwak Y.-S. , Meinecke R. , Kola R.R. , Rozgonyi G.A. , Kwack K.D. 
Published: March 2011

AbstractUsing thermal wave mapping and imaging techniques in conjunction with x-ray transmission topography and transmission electron microscopy, precipitation behavior of various fast and slowly diffusing metallic impurities such as Au, Co, Cu, Fe, Mo, Ni, Pd, Pt, W and Zn in Czochralski Si following rapid thermal processing are investigated. Our data have shown that thermal wave signal is sensitive to certain types of metal-induced surface defects (most likely metal silicides) and associated crystallographic defects. In addition, the comparison between thermal wave and x-ray imaging methods shows an interesting speciesdependent complimentary relationship.
Crystal Nucleation in Amorphous Si Films on Glass Substrate by Si+ Ion Implantation
Authors: Yamaoka Tomonori , Oyoshi Keiji , Tagami Takashi , Arima Yasunori , Tanaka Shuhei 
Published: March 2011

AbstractCrystallization of amorphous Si films on a glass substrate using Si+ ion implantation is investigated. 100keV and 180keV Si+ ion implantations into 600nm-thick amorphous Si layers crystallize half and almost all of the film thicknesses, respectively. This result demonstrates that crystallization by ion implantation, which contains both crystal nucleation and grain growth, is due to ion-solid interaction, and not to “pure” thermal effect by ion beam heating. Furthermore, two distinct regions are observed in transmission electron microscopy investigation of grain size at different depths of crystallized Si/SiO2 multi-layer specimens. The deep region below the projected range is composed of grains smaller than in the shallow region. This result is strongly related with crystal nucleation and growth kinetics by ion implantation.
Substrate Effects on the Kinetics of Solid Phase Crystallization In a-Si
Authors: Haji L. , Joubert P. , Guendouz M. , Duhamel N. , Loisel B. 
Published: March 2011

AbstractThe effect of substrate nature on the solid phase crystallization at 600 °C of a-Si deposited by low pressure chemical vapor deposition is investigated by x-ray diffraction and transmission electron microscopy. The nucleation rate varies slightly resulting to a weak variation in the final grain sizes as a function of the substrate type. In all cases the grain growth mode is found to be three dimensional. In contrary, a drastic effect of the substrate is observed for films deposited by plasma enhanced CVD. Fast crystallization is obtained on indium tin oxide (ITO) resulting to small grain poly-Si, whereas the crystallization is retarded on glass leading to an increase in the grain size.
Crystallization Processes in Amorphous Hydrogenated Silicon Based Alloys
Authors: Demichelis F. , Pirri C. F. , Tresso E. , Battezzati L. , Giamello E. , Menna P. 
Published: March 2011

AbstractAmorphous and microcrystalline films of silicon and silicon carbide have been deposited by means of PECVD at low substrate temperature (200°C), with reactive gases highly diluted in H2. Devices quality a-Si:H films have been annealed in vacuum at temperatures in the range 200- 1000 °C. The transition from amorphous to crystalline structure was studied by X-ray, Raman and I.R. spectroscopies, optical analysis in UV-VIS-NIR region, Transmission Electron Microscopy, Differential Scanning Calorimetry and Electron Spin Resonance measurements. By comparing the results of the two methods to obtain microcrystalline films we have deduced information on the process of growth of Si and SiC microcrystals.
Crystallization of Amorphous Si In Al/Si Multilayers
Authors: Konno Toyohiko J. , Sinclair Robert 
Published: March 2011

AbstractThe crystallization of amorphous Si in a Al/Si multilayer (with a modulation length of about 120Å) was investigated using transmission electron microscopy, differential scanning calorimetry and X-ray diffraction. Amorphous Si was found to crystallize at about 175 °C with the heat of reaction of 11±2(kJ/mol). Al grains grow prior to the nucleation of crystalline Si. The crystalline Si was found to nucleate within the grown Al layers. The incipient crystalline Si initially grows within the Al layer and then spreads through the amorphous Si and other Al layers. Because of extensive intermixing, the original layered structure is destroyed. The Al(111) texture is also enhanced.
Controlled Interface Roughness in GaAs/AlAs Superlattices
Authors: Miller William R. , Boettinger W. J. , Tseng W. F. , Pellegrino J. , Comas J. 
Published: March 2011

AbstractWe report the results of our study of controlled interface roughness in low-order GaAs/AlAs superlattices. Samples were prepared using either the interrupted growth or the migration-enhanced epitaxy (MEE) technique. The samples were prepared with m atomic planes of GaAs and m atomic planes of AlAs (m × m) per modulation wavelength and repeated p times. For this study, m = 1 or 3. The samples were studied using X-ray diffraction. The interrupted growth samples both showed a split in one diffraction line indicating layers were not of integral order while the MEE samples showed no splitting, indicating integral order layers.
Periodicities in the X-Ray Diffraction of Low Order ALAS/GAAS Superlattices
Authors: Pellegrino Joseph , Qadri S. , Tseng W. , Miller W. R. , Comas J. 
Published: March 2011

AbstractIn this work we examine the physical properties for the superlattice system (GaAs)n1 (AlAs)n2/GaAs(100) for low values of n1 and n2, i.e., n1 = n2 = 3, 6, 12. Normal, interrupted growth, and migration enhanced epitaxy (MEE) growth techniques were used to grow the superlattice structures in a molecular beam epitaxy system. X-ray diffraction spectra were obtained, and the major and satellite peak positions were analyzed to obtain the superlattice periodicity. An analysis of the major diffraction peaks and their associated satellites produced superlattice periodicity in good agreement with theory. Diffraction peaks were also observed in regions adjacent to the primary diffraction peaks which did not occur in the expected satellite positions. An analysis of these peaks relative to the primary peak indicate periodicities corresponding to layer thickness greater than the intended period. One possible cause for these periodicities is growth conditions that exist during the growth of the superlattice which result in the deposition of fractional monolayers. In this study we present results which suggest that an arsenic-deficient growth condition may be a contributing factor in the deposition of fractional monolayers.
Material Requirements for Reversible Phase Change Optical Recording
Authors: Rubin Kurt A. 
Published: March 2011

AbstractThe science and technology underlying phase change reversible optical storage, with an emphasis on the media, are reviewed. The transformation kinetics and their effect on writing (amorphization), erasing (crystallization) and long-term data stability are discussed. Phase separation is shown to affect cyclability and cause increased media noise. A readback CNR of 65.0 db was obtained by eliminating grooves as a source of media noise and using a recording layer which crystallizes into a cubic phase. Recording performance at short wavelengths is discussed.
Anomalous Point Defect Injection During Pulsed Laser Melting Processes: Direct Evidence of Gai and Asi Profiles in GaAs
Authors: Chang Yih , Sigmon Thomas W. 
Published: March 2011

AbstractSignificant point defect injection during a pulsed laser melt process is reported for the first time. Heteroepitaxial InxGa1-xAs/GaAs layers fabricated by a pulsed laser induced epitaxy technique are used in this study. Transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) and secondary ion mass spectrometry (SIMS) are employed to study the redistribution behavior of each species on the atomic scale. It is found that both the Si dopant species and the Ga, As, and In host atoms are injected into the underlying GaAs substrate. These species are then significantly redistributed, forming near spherical As-rich regions. Direct evidence of Asi and Gai (Ga and As interstitialcies) profiles in the GaAs substrate are also obtained for the first time. A hypothesis, based upon the combined effects of concentration impulse and large temperature gradients across the liquid-solid interface, is proposed to explain the significant solid phase diffusion observed during the pulsed laser melting process. We estimate the temperature gradient induced electric field during the process to be on the order of 104V/cm.
Nanostructure Evolution During the Transition of TiO2, PbTiO3 and PZT
from GELS to Crystalline thin Films.
Authors: Kang Z. C. , Gupta A. , Mckelvy M. J , Eyring L. , Dey S. K. 
Published: March 2011

AbstractThe nanostructure evolution of PZT, PT and T thin films has been studied by high-resolution electron microscopy (HREM) supported by other techniques such as thermal analysis, thermal mass spectrometric analysis and X-ray diffraction analysis. The evolution follows a common progression from amorphous film, to the development of condensed regions that develop crystalline order, to the final polycrystalline oxide thin film. If the precursor gel contains lead, the film develops fluctuating surface “blisters” that evolve to an oxide final product as well. Minor structural and compositional differences exist across the final oxide thin film.
Metastable Pyrochlore Structures in Sol Gel Spin Coated Lead Titanate Thin Films on Silicon Substrate
Authors: Lee Jeon-Kook , Jung Hyung-Jin , Kim Chong-Hee 
Published: March 2011

AbstractHigh quality lead titanate thin films were fabricated by spin coating on a silicon substrate. The resulting dried gel layers were uniform in thickness through 2 ' area, and polycrystalline perovskite structures developed almost crack free with a heat treatment above 500°C in films with thickness above 0.36μm.Metastable pyrochlore structures were observed in films with thickness of 0.16,μm when heat treated at 500 and 600 °C. But these structure did not appear in films with thickness of 0.36μm.The thickness dependencein crystal structure of films was studied by varing the substrate condition and analyzing the interface between the.film and. substrate. In native oxide films on silicon substrates, amorphous dried gel layers were heterogeneously nucleated. Metastable cubic pyrochlore structure could be crystallized in amorphous native oxide (cubic property in random network structure).
Oxidation Kinetics of Yba2Cu3OT7-x Thin Films in the Presence of Atomic Oxygen and Molecular Oxygen by In-Situ Resistivity Measurement
Authors: Yamamoto K. , Lairson B. M. , Bravman J. C. , Geballe T. H. 
Published: March 2011

AbstractThe kinetics of oxidation in Yba2Cu3O7-x thin films in the presence of molecular and atomic oxygen ambients have been studied. The resistivity of c-axis, a-axis, and mixed a+c axis oriented films, deposited in-situ by off-axis magnetron sputtering, was measured as a function of time subsequent to a change in the ambient conditions. The oxidation process is shown to be thermally activated and can be characterized by a diffusion model with an activation energy which varies from approximately 1.2eV in the presence of molecular oxygen to 0.6eV for a flux of 2×1015 oxygen atoms/cm2sec. In both cases, diffusivity is found to be insensitive to oxygen stoichiometry, but the rate of oxidation is found to be sensitive to the microstructure and orientation of the films.
Nucleation and Growth kinetics of Cu2O During Reduction of CuO Thin Films
Authors: Li Jian , Tu K. N. , Mayer J. W. 
Published: March 2011

AbstractThe combination of 16O(α, α)16O oxygen resonance measurement and transmission electron microscopy (TEM) provides an unique and effective method to study the kinetics of nucleation and growth of Cu2O phase during reduction. In situ TEM observation showed that isolated and large Cu2O grains emerge from the small CuO grain matrix and the growth of Cu2O grains is linear with time. We propose that the discontinuous morphology of grain growth of Cu2O is due to the migration of the Cu2O-CuO phase boundary induced by oxygen out-diffusion along the moving phase boundary. Based on the classical analysis of phase transformation by Johnson, Mehl and Avrami, the activation enthalpy of nucleation of Cu2O phase in the CuO matrix has been deduced as ΔEn=2.3 eV. The specific interfacial energy between CuO and Cu2O phases has been estimated as 0.5 eV/atom.