bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epitaxial Solid-Solution Films of Immiscible MgO and CaO
Authors: Hellman E. S. , Hartford E. H. 
Published: April 2011

AbstractMetastable solid-solutions in the MgO-CaO system grow readily on MgO at 300°C by molecular beam epitaxy. We observe RHEED oscillations indicating a layer-by-layer growth mode; in-plane orientation can be described by the Matthews theory of island rotations. Although some films start to unmix at 500°C, others have been observed to be stable up to 900°C. The Mgl-xCaxO solid solutions grow despite a larger miscibility gap in this system than in any system for which epitaxial solid solutions have been grown. We describe attempts to use these materials as adjustable-lattice constant epitaxial building blocks
Implications of Interfacial Coupling and Strain on the Magnetic and Structural Ordering of Fe3O4/NiO Superlattices
Authors: Lind David M. 
Published: April 2011

AbstractHere we review recent work on the preparation and characterization of magnetically ordered oxide Fe3O4/NiO superlattices. The materials were prepared by oxygen plasma-assisted molecular beam epitaxy. Their structural ordering was studied by x-ray, neutron, and RHEED electron diffraction techniques, and the superlattices are found to form as highly coherent strained-layer modulated single crystals. The magnetic ordering studies, using SQUID magnetometry, ferromagnetic resonance, and neutron diffraction, indicated strong interfacial coupling between the ferrimagnetic Fe3O4 layers and the antiferromagnetic NiO layers, with the magnetic ordering in each layer altered by the proximity to the magnetic moments in the adjacent layer. Strain and other layer-thickness effects are also evident in these magnetic layered structures. The special influence of interlayer coupling and strain on the Fe3O4 Verwey transition are discussed.
Microstructural Studies of Ferroelectric Bi2VO5.5 Thin Films With LaNiO3 Electrodes
Authors: Beesabathina D. Prasad , Salmanca-Riba L. , Hegde M. S. , Satyalakshmi K. M. , Prasad K. V. R. , Varma K. B. R. 
Published: April 2011

AbstractThin films of Bi2VO5.5 (BVO), a vanadium analog of the n = I member of the Aurivillius family, have been prepared by pulsed laser deposition. The BVO films grow along the [001] direction on LaNiO3(LNO) and YBa2Cu3O7 (YBCO) electrode buffer layers on LaA- IO3(LAO) substrates as obtained from X-ray diffraction studies. The microstructure of the films and of the interfaces within the film and between the film and the substrate were characterized using transmission electron microscopy. The in-plane epitaxial relationship of the rhombohedral LNO on perovskite LAO was [100] LNO // [100] LAO and [001] LNO // [001] LAO. High resolution lattice images showed a sharp interface between LNO and LAO. However, the LNO film is twinned with a preferred orientation along the growth direction. The BVO layer is single crystalline on both LNO/LAO and YBCO/LAO with the caxis parallel to the growth direction except for a thin layer of about 400 Å at the interface which is polycrystalline.
Silicon Oxynitride and Oxide-Nitride-Oxide Gate Dielectrics by Combined Plasma-Rapid Thermal Processing
Authors: Ma Y. , Hattangady S.V. , Yasuda T. , Niimi H. , Gandhi S. , Lucovsky G. 
Published: April 2011

ABSTRACTWe have used a combination of plasma and rapid thermal processing for the formation of thin gate-dielectric films. The bulk dielectric films investigated include silicon oxide, oxynitride and multilayer oxide-nitride-oxide heterostructures formed by plasma-assisted oxidation, remoteplasma-enhanced chemical-vapor deposition (remote-PECVD) followed by post-deposition rapid thermal annealing (RTA). Auger electron spectroscopy (AES) and infrared absorption spectroscopy (IR) have been used to study the chemistry of interface formation and the bulk dielectric chemical bonding, respectively. Electrical characterization of MOS capacitor structures incorporating these dielectrics was performed by conventional capacitance and current voltage techniques, C-V and I-V, respectively.
In-Situ Multiprocessing of Ultrathin Silicon Nitride Capacitors for Advanced Dram Cells
Authors: Thakur Randhir P.S. , Hawthorne Rick , Mathews Viju K. , Fazan Pierre C. , Werkhoven Chris J. , Granneman Ernst , Wilhelm Rudy 
Published: April 2011

ABSTRACTUltrathin silicon nitride capacitors were fabricated using in-situ multiprocessing technology. In this paper we present comparative studies of capacitor formation using standard furnace processing, rapid thermal processing (RTP), and cluster tool processing of ONO dielectric films. We show that, due to better interface control using cluster tool processing, higher capacitance can be obtained for a fixed leakage level for the same thickness of dielectric film when compared to furnace and rapid thermal processing. We discuss the structural and electrical properties of these films and show that, due to an oxide-free interface, the improved film quality results in lower leakage current density and higher reliability.
Ripple Pyrometry for Rapid Thermal Annealing
Authors: Fiory A. T. , Nanda A.K. 
Published: April 2011

ABSTRACTRipple pyrometry was proposed by Accufiber as a method for measuring wafer temperature in lamp-heated ovens. The technique obtains the wafer temperature from the wafer emittance radiation by simultaneously determining the effective emittance of the wafer and suppressing the interference from reflected lamp radiation. This paper reviews the technique for rapid thermal annealing and presents experimental results on silicon wafers instrumented with thermocouples and on processing blanket-film monitor wafers.
Optical Properties of Thermally Oxidized Silicon
Authors: Russo O.L. , Ravindra N.M. , Grow J.M. , Dumas K.A. 
Published: April 2011

ABSTRACTThe effect of furnace grown SiO2 layers on the optical properties of p- on p+ (100) Si substrates are investigated. The real part, n, of the complex refractive index n* = n + ik is calculated for radiation measured in the infra-red (IR) region between 3000 and 8000 cm−1 where the extinction coefficient, k, is negligible. The expression for n is obtained using the Fresnel coefficients for a three medium air-oxide-Si model. Strain in the silicon, which affects n, and caused by the stress in the SiO2 layer, increases with oxide thickness. X-ray diffraction (XRD) was used to measure the strain in Si for oxides layers ranging from native to 5124Å. The data showed a monotonically increasing normal compressive strain, εN (up to 0.47%) with oxide thickness, however, the corresponding change in n due to strain was not well defined. The effect of strain on the direct optical gap, Ed, at 3.46 eV when determined from results of other investigators by electroreflectance, suggests an average shift in Ed of about 25 meV.
Tunneling Current in Thin Silicon Dioxide Films
Authors: Zafar Sufi , Poler J. C. , Irene E. A. , Xu X. , Haines G. , Kuehn R. , Wortman J. J. 
Published: April 2011

ABSTRACTTunneling currents through thin silicon dioxide films on p-type silicon are measured at electric fields greater than 5 MV/cm. At the onset of the Fowler-Nordheim tunneling, oscillations in the current are observed. These oscillations are used for characterizing oxide films grown by three different processes: rapid thermal chemical vapor deposition, rapid thermal oxidation and thermal oxidation. We have explored the correlation between the oscillatory tunneling currents and the breakdown fields, and find a low field dc component to correlate with the breakdown fields and obscure the oscillations.
Electrical Activation of Boron in B+ + C+ Implanted Si during RTA with Different Heating Rates
Authors: Boudinov H. , Souza J.P. de 
Published: April 2011

ABSTRACTSilicon samples were single implanted with B+ (5 x 1014 cm−2, 50 keV) or co-implanted with C+ (5 x 1015 cm−2, 55 keV). Rapid thermal annealing (RTA) with heating rates (HR) of 1°C/s and 100°C/s with dwell time duration from 2 s to 15 min was used for B activation and the results compared with those provided by conventional furnace annealing (FA) for 30 min. In single implanted samples it was found that below 600°C or above 800°C the activation always increases with the annealing time. However, in the temperature range of 600-800°C and annealing times longer than 60 s a fraction of the initially activated B concentration deactivates. For temperatures in the range of 700-800°C the deactivation is followed again by another activation period. There is no noticeable difference between the activation yields after RTA with high HR for 15 min or FA for 30 min. In the C co-implanted samples the activation of boron saturates after few minutes. In addition the deactivation process is significantly reduced. A model assuming interaction of the B atoms with point defects and the C atoms with Si self- interstitial atoms is proposed to explain the results.
RTP Modeling for CVD and Thermal Oxidation
Authors: Sorrell F.Y. , Fordham M.J. , Yu Seungil , Neto A.J. Silva 
Published: April 2011

ABSTRACTA methodology for predicting the spatial and temporal distribution of film thickness is given for Chemical Vapor Deposition (CVD), and for thermal oxidation in Rapid Thermal Processor (RTP) systems, e.g. RTPCVD and RTO. The methodology is based on a wafer thermal model for the heat transfer to, from and within the wafer, a geometric ray trace algorithm to predict the radiant heat transfer from the lamps and reflectors to the wafer, a process model for the deposition or oxidation, and a gas flow model to predict the flow field in the RTP chamber. The CVD process is based on the Arrhenius deposition model, and thermal oxidation is based on a parallel diffusion model. The methodology has been validated by comparison of measured and predicted final film thickness from a cylindrical RTP system. The methodology is based on physical principles, with a minimum reliance on empirical relations and experimental data. As such it can be used for optimization of existing RTP designs and for the evaluation of proposed RTP configurations, such as new or novel lamp, reflector or chamber geometry.
In-Situ Doped Multi-Layer Epitaxial Structures with Abrupt Doping Transitions by Ultra High Vacuum Rapid Thermal Chemical Vapor Deposition (UHV-RTCVD)
Authors: ÅztÖjrk Mehmet C. , Muhsin S. , Ban Ibrahim , Harris Gari , Sanganeria Mahesh K. , Violette Katherine E. , Lee Archie 
Published: April 2011

ABSTRACTIn this work, we have studied boron doped multi-layer epitaxial structures as active regions of deep submicron (< 0.25 gtm)metal oxide silicon field effect transistors (MOSFETs).The structures were formed by ultra high vacuum chemical vapor deposition (UHV-RTCVD) using Si2H6 and B2H6 as the source gases and H2 as the carrier gas at 750°C - 800°C and at a total pressure of 80 mTorr. With the high growth rates provided by Si2H6, thermal budgets were kept below the limit of boron diffusion in Si resulting in extremely abrupt doping transitions pushing the depth resolution limits of secondary ion mass spectroscopy. The structures consist of three epitaxial layers with thicknesses ranging from 100 A to 625 T. The top layer on which the gate oxide is formed is lightly doped (lxl016 cm-3) to minimize vertical electrical field and ionized impurity scattering for higher MOSFET channel mobility. The second layer is doped to lx1018 cm-3 for suppression of punchthrough short channel effects and finally the third layer is doped to lx 1017 cm-3 to decrease the parasitic source/drain junction capacitance that will result from the relatively high doping density of the intermediate layer. To minimize dopant diffusion in Si, low temperature (or low thermal budget) processes were employed for gate oxidation and polysilicon implant activation. A typical source/drain activation anneal was also included in sample preparation in order to simulate complete MOSFET fabrication assuming remaining steps could be carried out at lower temperatures with little contribution to dopant diffusion. Our results indicate that after all process steps a lightly doped region can still be obtained under the gate oxide with sufficient thickness to contain the MOSFET inversion layer. In these structures, the threshold voltage is determined by the doping density and thickness of the top two layers and can be easily tailored to the desired value by optimizing these parameters. With the range of parameters used in this study, our measurements show threshold voltages within the range desired for 0.1 µm MOSFETs.
In-Situ Spectroscopic Ellipsometry for the Control of Si based Thin Multi-Layers Grown by UHV-CVD
Authors: Glowacki F. , Larre A. , Ferrieu F. , Campidelli Y. , Bensahel D. 
Published: April 2011

ABSTRACTIn-situ Spectroscopic Ellipsometry as a function of time is used to follow the growth of Si/SiGe Multi Quantum Well (MQW) structures. It provides both the starting surface control and the growth parameters understanding (thickness, growth rate, Ge content). Si and SiGe optical data were recorded at different temperatures on individual Si and SiGe layers. Using the measured indices and the known thicknesses of the layers, the experimental MQW data are fitted without adjustable parameters.
Control of Long-Lived Gas Emissions From Semiconductor Processing Equipment
Authors: Mocella Michael T. 
Published: April 2011

AbstractCertain perfluorocompounds (PFCs) - including CF4, C2F6, SF6, and NF3 - are widely used in gas phase thin film processing applications such as dry etching and CVD chamber cleaning. Through a combination of long atmospheric lifetimes and high infrared absorption cross sections, many PFCs have high global warming potentials (GWPs). Abatement of PFC emissions from semiconductor applications is consistent with existing and developing international, national, and industrial policies for the control of greenhouse gas emissions. For PFC applications in the semiconductor industry, there exist a number of promising options for emissions control. These options include destruction (comprising combustion, plasma, and chemical-thermal routes), recovery, and process replacement.
The Role of Microelectronic Integration In Environmental Control: A Perspective
Authors: Bhattacharyya Arup 
Published: April 2011

AbstractThe paper discusses the potential of silicon-based integration of disciplines of microelectronics, microoptics, and micromechanics, (MEOM), to achieve sensor-based smart subsystems for pervasive environmental applications. The author proposes a federally-focused initiative to establish an R & D institute to expedite progress and achieve global industrial leadership.
Evidence of Modifications of Micellar Interface In Sol-Gel
Glass
Authors: Catuara Christina M. , Lin Chhiu-Tsu 
Published: April 2011

ABSTRACTA new sol-gel procedure using micellar solutions has been developed to
immobilize local anesthetic drugs in optically transparent glass. Dibucaine
was selected as a direct emission probe at 77 K for determining the forms of
the anesthetic drug (free base, monoprotonated, and/or diprotonated) and its
location (hydrophobic core, interfacial layer or hydrophilic region) in
micelles. The photophysical properties of local anesthetics obtained in gels
are compared to those in solutions. During the gelation stage, the
predominant drug species was identified as free base dibucaine embedded in
the hydrophobic core of neutral as well as charged micelles. This
observation suggests that the micellar interface was modified by the large
hydrophilic gel surface during the gelation stage. The modified micellar
interface allows an increase in the partition of free base dibucaine into
the hydrophobic region. At the xerogel stage, however, the collapse of
micellar structure provides a direct interaction of dibucaine with the
acidic gel surface, leading to a formation of diprotonated dibucaine. The
results are discussed in terms of molecular basis of pharmacological
implications such as drug delivery, release, and transport under
microencapsulation conditions.
Optical Sol-Gel Materials Based on Binding and Catalysis by
Biomolecules
Authors: Zink Jeffrey I. , Dunn Bruce , Yamanaka Stacey , Lan Esther , Valentine J. S. , Chung K. E. 
Published: April 2011

ABSTRACTThe proteins copper-zinc Superoxide dismutase (CuZnSOD), cytochrome c,
myoglobin, hemoglobin, and bacterio-rhodopsin are encapsulated in stable,
optically transparent, porous, silica glass matrices prepared by the sol-gel
method such that the biomolecules retain their characteristic reactivities
and spectroscopic properties. The resulting glasses allow transport of small
molecules into and out of the glasses at reasonable rates but retain the
protein molecules within their pores. The transparency of the glasses
enables the chemical reactions of the immobilized proteins to be monitored
by means of changes in their visible absorption spectra. Silica glasses
containing the immobilized proteins have similar reactivities and
spectroscopic properties to those found for the proteins in solution. The
enzymes glucose oxidase and peroxidase were also encapsulated in transparent
silica glass matrices. Upon exposure to glucose solutions, a colored glass
is formed that can be used as the active element in a solid state optically
based glucose sensor. Likewise, gels containing oxalate oxidase and
peroxidase exhibit spectroscopic changes upon exposure to aqueous solutions
containing oxalic acid.
Liquid-Mix Synthesis of Oxide Powders and Thin Films Using A
Starch-Based Polymer
Authors: Tai Lone-Wen F. , Anderson Harlan U. 
Published: April 2011

ABSTRACTA commercially available water-soluble starch derivative was used as the
sole organic precursor in the Liquid-Mix synthesis of mixed-cation oxide
powders and thin films. The acidified polymer (by nitric acid) was able to
complex metal ions through the carboxylate ligands. Loosely agglomerated
fine powders as well as dense thin films of complex oxides have been
prepared using the same type of polymer. Oxide powders of Cr-doped lanthanum
aluminate and yttrium aluminum garnet both crystallized in a single step,
without forming any intermediate or second phases, when the amorphous resin
intermediates were calcined at 650°C and 750°C for 2 hours, respectively. It
was demonstrated that nitric acid could effectively reduce the viscosity of
the polymer-nitrate solution to make it suitable for spin coating process.
Dense thin films of Y(8 mol%)-doped ZrO2 were formed on Si and
A12O3 substrates by spin coating the polymeric
solution and heating at temperatures below 1000°C.
Evidence of Hexa-Coordination CcP Immobilized in Sol-Gel Glass
Authors: Meuret Les B. , Catuara C. M. , Mahloudji A. M. , Lin C. T. 
Published: April 2011

ABSTRACTAbsorption spectra of Cytochrome c Peroxidase (CcP) in phosphate buffer at pH 6.5 were recorded from 700 to 250 nm. The CcP solution was then encapsulated in sol-gel derived glass. The absorption spectra of CcP in xerogels were compared to those in buffer solutions. An increase in absorptivity at the Soret maximum, a decrease between 360 and 380 nm, and a spectral shift of the charge-transfer band from 645 to 620 nm was observed for CcP in gel matrix as compared to those in solution. Those spectral observations indicate a change in the coordination of the iron porphyrin ring in CcP from penta-coordinated in solutions to hexa-coordinated in gels. The oxidant H2O2, reductant Na2S2O4, and inhibitors NaF and KN3were allowed to diffuse through the porous glass, to react or to complex with the encapsulated CcP in sol-gel glass. The results show that H2O2and S2O42-lead to a change of oxidation state from Fe(III) to Fe(IV) and to Fe(II), respectively. Moreover, F-results in an enhancement of high-spin CcP, and N3- promotes a spin state change to a low-spin CcP. For CcP in xerogels, the chemical changes caused by inhibitors were found to be reversible when washed with deionized water. The possible applications of CcP immobilized xerogels in chemical and biochemical sensor technologies are discussed.
The Detection of Hexavalent Chromium by Organically Doped
Sol-Gels
Authors: Wong Phillip W. , Mackenzie John D. 
Published: April 2011

ABSTRACTThe sol-gel process can be used to produce porous inorganic matrices that
are doped with organic molecules. These doped gels can be used as a
quantitative method for the spectrophotometric determination of trace
concentrations of metallic ions. For the detection of hexavalent chromium,
malachite green was used as the dopant. Preliminary results indicate
concentrations on the order of 5 ppb are detectable using this method.
New Routes to Nanocomposite Materials
Authors: Hunt Arlon J. , Cao Wanqing 
Published: April 2011

ABSTRACTNew composite materials were prepared by using aerogel as a matrix for gas
phase decomposition. Various gases were infiltrated into the open pore
aerogel structure which were subsequently decomposed thermally by the
catalytic action of the aerogel. Composites of silica aerogel with carbon,
silicon, iron, and iron oxides were prepared. The method is applicable to a
wide range of new composite materials. Materials produced this way contain
nanometer-sized deposits that can give rise to size induced quantum
effects.
Synthesis of Wc-Co Nanocomposites Using Polymer as Carbon
Source
Authors: Manthiram A. , Zhu Y. T. 
Published: April 2011

ABSTRACTCeramic-metal composites such as WC-Co are attractive for cutting-tool
applications as they have high hardness, chemical inertness and resistance
to heat. The properties and performance of these composites can be enhanced
by keeping the size of the components on a nanometer scale. Synthesis of
WC-Co nanocomposites generally involves gas-phase carburization. We have
developed a novel approach in which a polymer precursor such as
polyacrylonitrile serves as an in situ source for carbon.
The WC-Co nanocomposites formed are characterized by x-ray diffraction and
electron microscopy. The synthesis and processing conditions such as firing
temperature, time and atmosphere play a critical role in obtaining
phase-pure products.
Conversion of Polymers of Methyl- And Vinylsilane To Sic
Ceramics
Authors: Hurwitz Frances I. , Kacik Terrance A. , Bu Xin-Ya , Masnovi John , Heimann Paula J. , Beyene Kassahun 
Published: April 2011

ABSTRACTPoly(methylsilane) and poly(vinylsilane) were synthesized using a titanocene
catalyst, and their pyrolytic conversion to ceramics was followed using a
combination of thermal analysis and infrared spectroscopy. The two polymers
have distinctly different backbone structures, as determined by
29Si NMR; methylsilane polymerizes to a polysilane, while
vinylsilane polymers have a predominately polycarbosilane backbone, with
some polysilane structure as well. The pyrolysis path and char yield were
dependent primarily on backbone structure, with little influence of polymer
molecular weight. The majority of the weight loss on conversion occurs below
650 °C, although bond rearrangement continues to 1400 °C. Poly(vinylsilane)
produced a C-rich Si-C ceramic in which the carbon was dispersed on a
sufficiently fine level to show resistance to oxidation on heating in air to
1400 °C.
Factors Affecting Strength of Agglomerates Formed During Spray
Drying of Nanophase Powders
Authors: Maskara A. , Smith D.M. 
Published: April 2011

ABSTRACTNanosized silica particles dispersed in various solvents were spray dried
and the change in size distribution, agglomerate strength, and strength
distribution was determined. The effect of solvent surface tension, pH, and
particle surface chemistry on strength of agglomerates formed during spray
drying was studied for particle sizes between 15 and 500 nm. Alcohol/water
mixtures having different surface tension, and water at different pH levels,
were employed to separate the effects of capillary pressure and surface
hydroxyl condensation reactions. The agglomerate strength was determined
using an ultrasonic measurement technique. The particle size was determined
using sedimentation. The strength and strength distribution of agglomerates
was found to depend on the solvent surface tension, solubility (pH), and
primary particle size.