bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epitaxial Waveguiding KNbO3 Thin Films Grown By RF-Sputter Deposition
Authors: Thöny Silvia Schwyn 
Published: April 2011

AbstractThe physical and optical properties of KNbO3 layers grown on (001) oriented spinel and MgO substrates by planar rf-sputter deposition were studied. Rutherford Backscattering measurements showed that stoichiometric films could be obtained by using K2CO3 enriched targets and 100% argon as a sputtering gas. The x-ray diffraction spectra showed that single crystalline tetragonal films could be obtained at temperatures in the range of 580–610°C. Furthermore, channelling experiments indicated good crystal quality with a χmin of 40%. High resolution Transmission Electron Microscopy of the films revealed epitaxial growth, but also domains with a typical width of 10–20 nm. Moreover, it was possible to excite waveguide modes with losses of only 1.1 dB/cm at λ = 632.8 nm. The nonlinear optical coefficient d31 was determined by the Maker-fringe technique using the 1.06 μm Nd:YAG laser fundamental wavelength. This yielded a d31 value of 5 pm/V. The electro-optic properties was investigated by phase modulation technique in a Michelson interferometer.
Multilayer Epitaxial Ferroelectric nx(SrTiO3/PbTiO3) Thin Films Prepared By The Sol-Gel Technique
Authors: Lou Yudan , Xu Yuhuan , Mackenzie John D. 
Published: April 2011

AbstractMultilayer epitaxial ferroelectric PbTiO3 and SrTiO3 thin films were grown alternatively on single crystal SrTiO3 (001) substrate by the sol-gel technique in this study. Lead titanium double metal alkoxide and strontium titanium double metal alkoxide were used for dip coating. By controlling the dip coating speed and the concentration of sol-gel solution, different thickness of films was obtained. The average thickness of each PbTiO3 or SrTiO3 layer was 120 Å which was measured by SEM method. By using XRD the structure of the epitaxial multilayer films was examined. The epitaxial PbTiO3 and SrTiO3 thin films could be obtained at 700°C and 800°C respectively. The change of transmittance with wavelength on 12( 6×[SrTiO3/PbTiO3]) layer films was measured. The structure and the optical properties of the films were discussed.
Aging Characteristics of Ferroelectric Epitaxial BaTiO3/YBa2Cu3O7 Heterostructures
Authors: Harkness Samuel D. , Viatella J. W , Nagabushnam V. , Singh R. K. 
Published: April 2011

AbstractThe nature of ferroelectric aging of epitaxial BaTiO3YBa2Cu3O7 heterostructures grown by laser deposition was investigated as a function of rricrostructure in the dielctric layer. Molar amounts of SrTiO3 were then substitutionally added to analyze the effect on the rnicrostructure and electrical properties. Corresponding shifts in c/a ratio and curie temperature were correlated to changes in aging rate (%δC/decade time). Microstructural analysis was provided by high-resolution x-ray diffraction (HRXRD), and Rutherford backscattering spectroscopy (RBS). Results indicate a moderate upward shift in c/a ratios from theoretical values due to increasing lattice strain across the bilayer interface. Minimum channel yields in RBS spectra were maintained between 6–8% for BaTiO3 purities above 60 %. Dielectric measurements were conducted using an impedance analyzer equipped with an isothermal chamber capable of maintaining ±1°C. The dielectric properies were consistent with c-axis oriented BaTiO3 values (k=120, D=.02)Minimum aging rates are observed at the lower c/a ratio compositions to be as low as .07%δC/decade.
Rapid Thermal Chemical Vapor Deposition of Titanium Nitride for Barrier Application
Authors: Fröschle B. , Leutenecker R. , Cao-Minh U. , Ramm P. 
Published: April 2011

ABSTRACTToday there are many investigations of titanium nitride (TiN) deposition as diffusion barriers in microelectronics, especially with Chemical Vapor Deposition (CVD) techniques. In our newly developed Rapid Thermal CVD (RTCVD) process, we combine the conventional LPCVD process of TiN using titanium (IV) chloride and ammonia with the advantages of a RTCVD reactor. With regard to the ability of fast temperature change especially to reach the anneal temperature and to cool down to room temperature in the annealing ambient, it is possible to perform the entire processing sequence within one single processing chamber. The influences of deposition temperature, as well as the effects of the temperature during a subsequent in situ anneal step on the properties of the layers is analyzed. TiN layers with a specific resistivity as low as 250 μΩ-cm even at deposition temperatures of 450 °C are obtained. The resistivity of the layers and the chlorine content is nearly half of the films without an anneal step. The capability of these layers for ULSI application is shown by depositing TiN in submicron contact holes with a step coverage of nearly 100 %.
Ultrathin Gate Dielectrics grown in Mixtures of N2O and O2 Using Rapid Thermal Oxidation
Authors: Grant John M. , Hsieh Tzu-Yen 
Published: April 2011

ABSTRACTA study comparing the oxide growth and electrical properties of 60Å oxides grown in different mixtures of O2 and N2O was performed. The oxide growth for all mixtures examined, as well as that of the pure O2 and N2O cases, fit a Deal-Grove oxidation model modified for Rapid Thermal Oxidation (RTO). Linear growth rate constants found for both a simple linear model and the modified Deal-Grove model are significantly greater for mixtures containing only 35% O2 than for pure N2O oxidation. The uniformity of the oxide growth across the wafer for the gas mixtures resembles that seen in pure N2O oxidation rather than pure O2 oxidation. The electrical properties were measured using Surface Photo-Voltage (SPV) techniques along with conventional Capacitance-Voltage (C-V) and Current-Voltage (I-V) techniques. Oxides grown in 100% N2O showed significantly higher oxide charge when compared to oxides grown in 100% O2. An in-situ anneal in an Ar ambient reduces the oxide charge for all gas mixtures examined. The higher oxide charge accompanies an increase in the interface trap density for the oxides grown in 100% N2O. The in-situ anneal reduces the interface trap density for oxide grown in 100% O2 but has little effect for oxides grown in 100% N2O. The interface trap density is reduced by the in-situ annealing for oxides grown in mixtures of O2 and N2O.
Passivation of III-V Semiconductor Surfaces Using Light Assisted Integrated Processes
Authors: Dulac Olivier , Nissim Yves I. 
Published: April 2011

ABSTRACTPassivation of III-V semiconductor surfaces and especially the GaAs surface has been studied for over two decades without significant breakthrough. However, III-V device performances are still often limited by surface properties. In particular field effect behaviour in GaAs has been impossible to obtain due to the Fermi level pinning at the surface of this material. This paper presents an integrated sequence of low thermal budget processes to provide contamination control at the GaAs surface leading to very promising field effect on GaAs.In-situ surface cleaning using a Distributed Electron Cyclotron Resonance Microwave plasma (DECR MMP) has been integrated with a thin dielectric film deposition facility using light assisted CVD technics. Photoluminescence results carried out on GaAs surfaces have demonstrated that exposure to a hydrogen plasma induces lower recombination rates on these surfaces. Bulk diffusion of hydrogen during this process can be controlled and eliminated using an integrated Rapid Thermal Annealing (RTA). Finally, in-situ encapsulation by a dielectric allows one to stabilize the electronic properties of the surface for passivation applications. A silicon nitride film deposited by a direct UV photolysis deposition process has been developed for this study and is presented here.
Rapid Thermal Processing Requirements for 0.35-µm IC Technologies and Beyond
Authors: Moslehi Mehrdad M. 
Published: April 2011

ABSTRACTThis paper will present an overview of rapid thermal processing (RTP) technologies for fastcycle-time IC production. RTP has experienced significant advances in equipment design, process control capabilities, and unit process applications over the past eight years. The Microelectronics Manufacturing Science and Technology (MMST) program at TI successfully demonstrated CMOS IC production in a single-wafer factory with all-RTP thermal fabrication for various anneals, oxidations, and chemical-vapor depositions. The use of RTP in conjunction with other single-wafer processes enabled 0.35 µm IC fabrication with a 3-day cycle time. Selected RTP equipment, sensor, and process control developments will be reviewed. The RTP applications and requirements for state-of-the-art and future IC technologies will be described.
The Effect Of The Crystal Orientation Of The Formation Of The Oxygen-Deficient Magnetite
Authors: Wada Y. , Togawa T. , Kato H. , Tsuji M. , Tamaura Y. 
Published: April 2011

AbstractAn oxygen-deficient magnetite (Fe3O4–8) has been found to form by passing H2 gas through magnetite powder at 300°C with its spinel structure retained. The oxygen-deficient magnetite is a metastable phase in the transformation of magnetite into α-Fe. The lattice constant of the oxygen-deficient magnetite enlarged to 0.8407nm in the maximum value which is substantially larger than that of the stoichiometric magnetite (a0=0.8396nm). The formation mechanism of the oxygen-deficient magnetite was studied at 300°C using two specimens of magnetite powders with developed orientations on the (111) and (100) planes. These are referred to as (111)- and (100)-magnetite, respectively. The formation of α-Fe was suppressed over the crystal of (111)-magnetite, where wUstite and oxygen-deficient magnetite were formed while keeping the f.c.c. arrangement of the oxygen ions in the solid. On the other hand, over the (100)-magnetite, the formation of a-Fe was enhanced. It is considered that, on the (111)- magnetite, the Fe2+ ion formed by H2-reduction on the surface can move into interstices of the f.c.c. lattice of bulk to form the oxygen deficient state. This will come from the fact that the Fe2+ ion on the surface is so strongly supported with three Fe-O bondings that the Fe2+ ions cannot readily diffuse on the surface when the surface oxygen ions are removed on the (111)- magnetite.
Sol-Gel-Derived Silica Films With Tailored Microstructures for
Applications Requiring Organic Dyes
Authors: Logan Monica N. , Prabakar S. , Brinker C. Jeffrey 
Published: April 2011

ABSTRACTA three-step sol-gel process was developed to prepare organic dye-doped thin
films with tailored porosity for applications in chemical sensing and
optoelectronics. Varying the acid- and base-catalyzed hydrolysis steps of
sols prepared from tetraethoxysilane with identical final H2O/Si
ratios, dilution factors and pH resulted in considerably different
distributions of the silicate polymers in the sol (determined by
29Si NMR) and considerably different structures for the
polymer clusters (determined by SAXS). During film formation these kinetic
effects cause differences in the packing and collapse of the silicate
network, leading to thin films with different refractive indices and volume
fraction porosities. Under conditions where small pore-plugging species were
avoided, the porosities of as-deposited films could be varied by aging the
sol prior to film deposition. This strategy, which relies on the growth and
aggregation of fractal polymeric clusters, is compatible with the low
temperature and near neutral pH requirements of organic dyes.
What are the Molecules of Which the Samples of Metal Alkoxides
do Really Consist ?
Authors: Turova N.Ya. , Kozlova N.I. , Turevskaya E.P. , Rogova T.V. , Kessler V.G. 
Published: April 2011

ABSTRACTOn the basis of consideration of the properties of AI, In, Ln, Ti, Zr, Hf,
NbO3+, MoO4+, WO4+, MoO22+ MO22+, Fe, Co, Ni alkoxide derivatives the main regularities in
poly- and oligomerization properties have been deduced:1) The molecular complexity increases in time (aging) and on action of
alcohols. This process is followed by the increase in the melting and
boiling points, decrease in solubility in ROH and weakening of colour. In
the mass-spectra - in connection with the temperature of transition into the
gas phase - increases the stability of products with lower molecular masses.
2) oligomerization occurs on dissolution in aromatic hydrocarbons or on a
short thermal treatment (melting, distillation). The oligomerization
products possess lower thermal constants, higher solubility in ROH and more
intense colour. Their mass- spectra are containing the fragments of higher
masses corresponding to oligomers existing apparently also in the condensed
phase.The mastering of these regularities permits the monitoring of molecular
composition and thus physicochemical properties of the samples which are of
importance for their technological application.The presence of oxoalkoxides in the “M(OR)n” samples should be taken into
consideration on the preparation of solutions used in the synthesis of
powders and films of pure simple and mixed oxides.
Mechanochemical Synthesis of ZrTiO4 Precursor from
Inhomogeneous Mixed Gels
Authors: isobe Tetsuhiko , Okamoto Yutaka , Senna Mamoru 
Published: April 2011

ABSTRACTEffects of vibration ball-milling of a powdered mixture of two gels,
prepared from mixing ZrO2 andTiO2 sols, on
crystallization processes during heating are studied in order to elucidate
enhanced mechanochemical reactions with the aid of hydroxyl groups.
TiO2 (anatase) and ZrO2 (tetragonal) crystallized
at 698 K and 712 K, respectively, when heating non-milled gel mixture at 10
K min1 in air. Few reactions between the two phases were detected
below 1023 K. After vibro-milling a powdered gel mixture at room temperature
for 3 to 30 h, ZrTiO4 (orthorhombic) crystallized directly from
non-crystalline precursors on heating to 1023 K. The fraction of
crystallizedZrTi04, determined by Raman spectroscopy,
increased linearly with increasing the index of micro-homogeneity for
non-heated gels. We suggest that short-range ordering of ZrTiO4
rather than crystallization of individual oxides occurs through the
non-thermal atomic movement between different metallic species under
mechanical stress.
Phase Relations And Conductivity In
ZrO2-Sc2O3-La2O3
System
Authors: Yamaji Akihiko , Ishii Takao , Kanzaki Masami 
Published: April 2011

ABSTRACTThe oxygen-ion conductor 0.88ZrO2-0.12Sc2O3
has a discontinuous change in ion conductivity at about 660°C. This change
accompanies the structural transition from rhombohedral to cubic phase.
Since the high temperature cubic phase shows large ion conductivity, it is
of interest to examine whether or not the cubic phase stabilizes in the low
temperature region by another dopant . By adding only 0.005 mole %
La2O3, the cubic phase is stabilized below about
500 °C without any loss of conductivity compared with
0.88ZrO2-0.12Sc2O3. The ion conductivity
of cubic stabilized
ZrO2-Sc2O3-La2O3
system is around 1×10-1 S/cm at 800°C. Cubic phase stabilization
using second dopant in a ZrO2-Sc2O3 system
led to the finding of a fast oxygen-ion conductor in the
ZrO2-Sc2O3-La2O3
system.
Ormosils of High Hardness
Authors: Iwamoto Takashi , Mackenzie John D. 
Published: April 2011

ABSTRACTOrganically modified silicates (ormosils) of high hardness were prepared by
the reactions of tetraethoxysilane (TEOS) and polydimethylsiloxane (PDMS)
aided by ultrasonic irradiation. The mechanisms leading to the hard ormosil
formation were investigated by liquid state 29Si NMR
spectroscopy. PDMS chains were found to be broken into shorter chains and/or
4-membered siloxane rings during the reaction and finally, all PDMS chains
were chemically incorporated as short chains into silica networks. Vickers
hardnesses of the hard ormosils were measured and compared with those of the
hardest transparent plastics. Whereas the hardest transparent plastics have
Vickers hardness values of less than 25 kg/mm2, the hard ormosils
have Vickers hardnesses up to higher than 150 kg/mm2. A
theoretical model was developed for the calculation of Vickers hardnesses of
the hard ormosils and agreed well with experimental results. Predictions
based on this theory indicate that even harder ormosils can be made when
Al2O3, ZrO2 and TiO2 are
substituted for SiO2. Results based on these new ormosils are
also presented.
Hydrocarbon-Bridged Polysiloxane and Polysilsesquioxane Network
Materials.
Authors: Jamison Gregory M. , Loy Douglas A. , Assinkt Roger A. , Shea Kenneth J. 
Published: April 2011

ABSTRACTHexylene-and phenylene-bridged polymethylsiloxane xerogels X-2 and X-4,
respectively, were prepared by the sol-gel hydrolysis and condensation of 1,
6-bis(diethoxymethyl-silyl)hexane 1 and 1, 4-bis(diethoxymethysilyl)benzene
2 under acidic and basic conditions. These polymerizations afforded network
polymers in the form of wet gels within several hours. The gels were
processed to afford xerogels whose characteristics (determined by solid
state 13C and 29Si CP MAS NMR spectroscopy and
nitrogen sorption porosimetry) were compared and contrasted with those of
their analogous polysilsesquioxanes. 29Si CP MAS NMR indicates a
high, degree of hydrolysis and polycondensation; porosimetry measurements
reveal that the materials have significant surface areas, save for the
acid-catalyzed hexylene gels X-2.
Chromophore Dynamics in Sol-Gel Glasses and Xerogel Clad Fiber Optic Sensors
Authors: L'Esperance Drew , Browne Clarice A. , Chronister Eric L. 
Published: April 2011

ABSTRACTTime-resolved depolarization measurements are used to investigate rotational diffusion and optical energy transfer dynamics of chromophores incorporated into silica and aluminosilica solutions, gels, and glasses. The use of an organically doped sol-gel clad waveguide as a novel intrinsic fiber optic sensor device is also demonstrated, and advantages of time-resolved detection of the fiber optic sensor are illustrated.
Hydrothermal Processing of BaTiO3/Polymer
Films
Authors: Slamovich Elliott B. , Aksay Ilhan A. 
Published: April 2011

ABSTRACTHydrothermally derived films of BaTiCO3 were fabricated by
reacting thin layers of titanium organometallic liquid precursors in aqueous
solutions containing Ba(OH)2 and having a high pH. Cubic
submicron polycrystalline films of BaTiCO3 (thickness = 1 μm)
were formed at 70°C. Low concentrations of block copolymers of polybutadiene
and polystyrene were incorporated into the liquid precursor to prevent
precursor film cracking. Higher polymer concentrations allowed fabrication
of polymer/ceramic composite films by virtue of the low temperature used in
hydrothermal processing.
Sol-Gel Processing Using Aminofunctional Silanes
Authors: Cao Wanqing , Hunt Arlon J. 
Published: April 2011

ABSTRACTClear gels have been made from TEOS and the aminofunctional silane under
acid-catalyzed conditions and light scattering of the gels has been related
to pH and the concentration of fluoride ions in the sol as well as the
amount of the aminosilane used. We have succeeded in preparing a series of
gels containing Ni2+ or Cu2+ ions immobilized by
chelation either before or after the gel formation. Aerogels made from these
gels in particular, doped by the method of impregnation, have had a
homogeneous microstructure on the scale of only a few nanometers.
Structural Disorder and Thermal Dilatation Behavior in Cr-Doped
Mullite
Authors: Villar M.P. , Geraldia J.M. , Gago-Duport L. 
Published: April 2011

ABSTRACTLattice parameters of some different chromium-doped mullites obtained by a
sol-gel route and sintered at 1650° C have been determined from X-Ray
Diffraction data as a function of both temperature and Cr contents. Profile
refinements on the X-ray diffraction diagrams have been carried out, showing
that, at temperatures between 800° and 1535° C, an anisotropic thermal
expansion takes place for the a and b
lattice parameters of the Cr-doped mullite. We show that this anisotropic
expansion is dependent on the temperature increase and the chromium content
for the different compositions of the mullite crystals.
Microstructural Evolution of Titania Sol-Gel Thin
Films
Authors: Yan Yongan , Ray Chaudhuri S. , Chen Din-Guo , Bolker Barry , Sarkar Arnab 
Published: April 2011

ABSTRACTThin films of crystalline titania with different grain sizes and porosities
were prepared by dip-coating on Si (100) substrates starting from a sol-gel
process. Three synthesis procedures were developed and compared, using
acetylacetone (acac, with HCI) and acetic acid (HOAc) as modifying agents or
directly using hydrochloric acid as catalyst. The structural evolution of
the films was characterized by Glazing Angle X-ray Diffraction (XRD),
Spectroscopic Ellipsometry and Atomic Force Microscopy (AFM). Anatase phase
was observed on all of the films calcined at 440° C. The grain sizes and
crystallinity generally increased with calcination temperature. Thin films
obtained from acac- and HOAc-modified titanium sols had fine grains (50–80
nm) and less porosity (<10%) after calcination at 1000° C. Thin films
derived from the sol catalyzed directly with acid had the largest grains
(90–130 nm), higher crystallinity and greater porosity (17%).
Phenylation of Fullerene-C60
Authors: Taylor Roger , Avent Anthony G. , Birkett Paul R. , Crane Jon C. , Darwish Adam D. , Langley G. John , Kroto Harold W. , Walton David R. M. 
Published: April 2011

ABSTRACTC60 Cl6 can be phenylated and arylated to give derivatives of the type C60Ar5Cl, which may be readily converted to C60Ar5. The compounds C60Ar5 and various other phenylated derivatives have been isolated from the product of reaction of [60]fullerene with bromine/ferric chloride/benzene, and partially characterised.
First-Principles Determination of the Polarizabilities of Carbon Tubules as a Function of Length
Authors: Quong Andrew A. , Pederson Mark R. 
Published: April 2011

ABSTRACTWe use the local-density-approximation to the density-functional theory to determine the axial polarizabilities of fullerene tubules as a function of length and winding topologies. Specifically, we present linear polarizabilities for tubules of composition C12H24, C36H24, C40H20 and C60H24. The size-dependent variation in the dipole-coupled gaps between pairs of occupied and unoccupied levels leads to enhancements in the polarizability per valence electron as the length of the tubule increases. The results are compared to recent densityfunctional based calculations of the linear and nonlinear polarizabilities for fullerene and benzene molecules.
Occupied and Unoccupied Orbitals of C60 and C70 Probed with C 1s Emission and Absorption
Authors: Carlisle J. A. , Terminello L. J. , Hudson E. A. , Shirley E.L. , Himpsel F. J. , Jia J. J. , Callcott T. A. , Perera R. C. C. , Louie S. G. , StÖhr J. , Samant M. G. , Ederer D. L. 
Published: April 2011

ABSTRACTThe full spectrum of occupied and unoccupied σ and Π orbitals is presented for solid C60, C70, and graphite, using C1s emission and absorption spectroscopy. There are significant differences between C60 and C70, and even larger changes relative to their infinite analog graphite C∞. A comparison is made with photoemission and inverse photoemission results, along with first principles quasiparticle calculations.
Aem and Hrem Evaluation of Carbon Nanostructures in Silica Aerogels
Authors: Song X.Y. , Cao W. , Hunt A.J. 
Published: April 2011

ABSTRACTNanostructured carbon has been deposited in silica aerogels by chemical vapor infiltration using acetylene or ferrocene at moderate temperatures. Using analytical electron microscopy and high-resolution electron microscopy, we have observed various carbon rings and nanotubes in the silica aerogel-based carbon composite. Both X-ray microanalysis and nano-probe diffraction techniques have been used to confirm the presence of those carbon nanostructures. The morphologies and structural properties of the carbon nanotubes and rings have also been examined in detail.