bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal Stresses in Passivated Copper Interconnects Determined by X-Ray Analysis and Finite Element Modeling
Authors: Vinci R.P. , Zielinski E.M. , Bravman J.C.
Published: April 2011

Stresses in passivated copper lines were determined from strains measured using x-ray methods and compared to stresses calculated using finite element methods. Copper lines, 2 µm wide by 0.8 µm thick, were fabricated by DC magnetron sputtering and lift off patterning. The cross section of these lines was trapezoidal, with approximately 50° sidewalls. One set of samples was left bare, the others passivated with Si3N4 in several different thicknesses. Strain was determined using x-rays. Stress was calculated using elastic moduli adjusted for predominantly (111) fiber texture. Elastic-plastic finite element models provided comparisons of the effects of passivation thickness, rectangular and trapezoidal cross section, and mechanical anisotropy due to preferred texture on the hydrostatic stress in a line. A similar model for aluminum also provided a comparison case of stress as a function of passivation thickness.
The Effect of Variability Among Grain Boundary Energies on Grain Growth in Thin Film Strips
Authors: Frost H.J. , Hayashi Y. , Thompson C.V. , Walton D.T.
Published: April 2011

Grain growth in thin-film strips is important to interconnect reliability because grain boundary structures strongly effect the rate and mechanism of electromigration-induced failure. Previous simulations of this process have indicated that the transformation to the fully bamboo structure proceeds at a rate which decreases exponentially with time, and which is inversely proportional to the square of the strip width. We have also reported that grain boundary pinning due to surface grooving implies that there exists a maximum strip width to thickness ratio beyond which the transformation to the bamboo structure does not proceed to completion. In this work we have extended our simulation of grain growth in thin films and thin film strips to consider the effects of variations in grain boundary energy. Boundary energy is taken to depend on the misorientation between the two neighboring grain and the resulting variations in grain boundary energy mean that dihedral angles at triple junctions deviate from 120°. The proportionality between boundary velocities and local curvatures, and the critical curvature for boundary pinning due to surface grooving also both depend on boundary energy. In the case of thin-film strips, the effect of boundary energy variability is to impede the transformation to the bamboo structure, and reduce the width above which the complete bamboo structure is never reached. Those boundaries which do remain upon stagnation tend to be of low energy (low misorientation angle) and are therefore probably of low diffusivity, so that their impact on reliability is probably reduced.
In Situ Observations of Voiding in Metal Lines Under Passivation
Authors: Marieb T. , Bravman J.C. , Flinn P. , Madden M.
Published: April 2011

Movies showing high voltage scanning electron microscope (HVSEM) in situ observations of void motion in passivated metal lines were produced. By taking pictures of the line when the void morphology changes and combining these images digitally with a technique called morphing, a time-lapse movie is constructed with the minimum amount of stored images. The sequence of still images from which a movie is constructed are shown in this paper. This sequence demonstrates that wedge voids do not cause failure in near-bamboo pure Al lines; rather the void will move until it encounters a grain which it can grow across in a slit-like manner.
Statistics of CRack Initiation and Propagation
Authors: Quinones H. , Shatzkes M.
Published: April 2011

Statistics of fracture fatigue are derived based on essentially general models of crack propagation and initiation. In fact, the form of the distribution is invariant with respect to the crack propagation law, however, the parameters do depend on the details of the phenomena. When this dependence is known, i.e. extracted from experimental data, our results can be applied even in the case of changing environments. Thus, such problems as projections to use conditions and the efficiency of burn in procedures can be precisely formulated and resolved, often without the requirements of further testing. These advantages derive from our use of physical models in deriving the failure distribution. This was not previously the case where for the almost universally used log-normal distribution each new situation requires the establishment of new rules. In fact, the log-normal is usually pessimistic and requires ad-hoc rectification to account for curvature when plotted on log-normal paper!, and generally does not relate to the fatigue process.
Organic Polymer Dielectrics in Microelectronic Technologies: Reliability Requirements, Testing, and Qualification
Authors: Townsend P. H. , Heistand R. H. , Castillo D. , Stokich T. M. , Allen B. , Radler M. , Tarnowski T. , Blackson J. , Klassen H. , Miller B. , Theide H. , Strandberg J. , Karlsson A.
Published: April 2011

This work reviews the dependence of reliability testing results on material processing and properties for polymeric materials used in high density interconnection technologies.Specific data are presented for CyclotenesTM 3022 resins containing divinylsiloxane bisbenzocyclobutene, (CAS 117732-87-3). Silane coupling agents discussed in this study are 3-aminopropyltriethoxysilane (CAS 01760-24-3)(APTES) and 3-methacryloxypropyl trimethoxysilane (CAS 02530-85-0) (MOP-TMS).
Moisture-Assisted Crack Growth in Polymer Adhesive-Glass Sandwich Geometries
Authors: Ritter J. E. , Lardner T. J. , Prakash G. C. , Stewart A. J.
Published: April 2011

Moisture-assisted crack growth in polymer/glass interfaces was measured as a function of the applied energy release using a four-point flexure test coupled with an inverted microscope. The specimens consisted of two glass plates bonded together with a thin layer of epoxy adhesive. Roughening the surface of one of the interfaces increased its fracture resistance sufficiently so that crack growth on this interface was inhibited. Thus, crack growth would occur only on the “smooth” interface (one with the least fracture resistance) or in the case where both interfaces were smooth, dual cracking occurred. Finite element analysis was used to explain the observed crack growth results.
Diffusion-Induced Precipitation in Arsenosilicate Glass (AsSG)
Authors: Srinivasan Radhika , Nguyen Tue , Ho Herbert L. , Nguyen Tai D.
Published: April 2011

Diffusion-induced precipitation in arsenosilicate glass (AsSG) under high temperature anneal is studied by high resolution Transmission Electron Microscopy (TEM), and other techniques. Polycrystalline precipitates of a few hundred angstroms in size have been observed near the interface of AsSG and the silicon substrate, covering the entire interface area after high temperature anneal. It is proposed that high concentrations of arsenic (above the solid solubility limit) precipitate initially at nucleation sites near the AsSG/silicon interface. Further anneal-induced diffusion of arsenic to the interface promotes growth of the precipitates. As a result, the precipitates cover the entire interface area, and impede further As diffusion into the Si substrate. Techniques to avoid the precipitation process without compromising the thermal budget or reduced arsenic diffusion have been explored and will be discussed.
Study on Epitaxial Growth of CeO2 (110)/Si(100) in Conjunction with Substrate Off-Orientation
Authors: Inoue Tomoyasu , Yamamoto Yasuhiro , Satoh Masataka , Ohsuna Tetsu , Myoren Hiroaki , Yamashita Tsutomu
Published: April 2011

The substrate off-orientation effect is systematically studied on epitaxial CeO2(110) layers on Si(100), and the crystalline quality is significantly improved by enhancement of domains whose 〈110〉 is perpendicular to the offset-direction (Si〈110〉). AFM measurements indicate that the CeO2 layer surface consists of stripe-shaped facets and that their size is typically 100˜200 nm long, 20 nm wide and ∼3 nm high for a 150 nm-thick layer. RHEED and XTEM reveal that CeO2〈110〉 axis is inclined from wafer normal by the off-angle. The step arrangement at Si surface observed by XTEM relates closely to the inclination of the facets. It is found that off-orientation (≥∼,2.5°) leads to single crystal layer formation. RBS analyses verify that the crystalline quality is significantly improved, especially at the surface. The best result is obtained at the off-angle of 2.5°.
Infrared Sensor For CVD Deposition Of Dielectric Films
Authors: Niemczyk Thomas M. , Franke James E. , Zhang Songbiao , Haaland David M.
Published: April 2011

Infrared emission (IRE) spectra were obtained from two borophosphosilicate glass (BPSG) thin-film sample sets. The first set consisted of 21 films deposited on undoped silicon wafers, and the second set consisted of 9 films deposited on patterned and doped (product) wafers. The IRE data were empirically modeled using partial least-squares calibration to simultaneously quantify four BPSG thin-film properties. The standard errors of the determinations when modeling the 21 monitor wafers were < 0.1 wt% for boron and phosphorus content, 36 Å for film thickness, and 1.9°C for temperature. The standard errors of the determinations based on the product wafers were 0.13 wt% each for B and P content, 120 Å for film thickness, and 5.9°C for temperature.
Synthesis of the Carrier Doped Infinite-Layer Films by rf Thermal Plasma Evaporation
Authors: Kume A. , Yakabe H. , Shiohara Y. , Koshizuka N.
Published: April 2011

We tried to deposit (Sr1−xCax)0.9CuO2-δ films, so-called “the infinite-layer” structure, of (100) SrTiO3 substrates by using radio-frequency thermal plasma evaporation. The crysta structure of these films was confirmed by X-ray diffraction to consist of the (00l) oriented infinite-layer structure. However, the temperature dependence of resistivity showed no superconductivity in spite of varying ratios of Sr/Ca. A description is given of attempts to induce superconductivity in the infinite-layer films by the introduction of holes, namely by O2 plasma annealing and Na-doping.
Epitaxial Waveguiding KNbO3 Thin Films Grown By RF-Sputter Deposition
Authors: Thöny Silvia Schwyn
Published: April 2011

The 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

Multilayer 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

The 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

Today 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

A 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

Passivation 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

This 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

An 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

A 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

On 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

Effects 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

The 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

Organically 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

Hexylene-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

Time-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

Hydrothermally 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

Clear 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

Lattice 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

Thin 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

C60 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

We 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

The 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

Nanostructured 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.
Susceptibility Study of Site Selective Doped Fullerenes - K2RbC60, Rb3C60, K2CsC60, and Rb2CsC60
Authors: Baenitz M. , Heinze M. , Lüders K. , Werner H. , Schlögl R.
Published: April 2011

The superconducting properties of several binary and ternary fullerene compounds are investigated by means of ac susceptibility technique. The susceptibility X = X'-iX” is observed as a function of temperature for different magnetic field amplitudes (0.01 G - 20 G). The samples are characterized by X-ray diffraction (XRD) analysis and the fcc-lattice constants a0 are determined. Furthermore the influence of the preparation procedure, especially the treatment of the C60 starting material on the superconducting properties is discussed.
Plasma Potential Measurements and Strain Effects in Epitaxial GAN Grown on AlN Buffered Si(111) by Radio Frequency Reactive Sputtering
Authors: Meng W. J. , Perry T. A.
Published: April 2011

We have grown epitaxial GaN thin films on A1N buffered Si(lll) by radio frequency glow discharge sputtering. GaN growth direction strains and GaN E2 optical phonon energies are measured. At the same growth temperature, plasma potentials of the radio frequency glow discharge in which GaN is grown, GaN growth rate, and strain in GaN increase systematically as a function of increasing input power. The measured GaN E2 optical phonon energy scales with GaN lattice strain. Our results indicate the presence of significant intrinsic stresses in epitaxial GaN films and point to the importance of plasma characteristics in controlling the physical properties during plasma assisted thin film deposition.
Determining Interfacial Free Energies from Creep Experiments on Silver-Iron Multilayers
Authors: Josell D. , Wang Z.L.
Published: April 2011

Experiments were conducted on multilayer thin films to determine the free energies associated with silver/iron interfaces. Creep studies determined the loads for which the multilayers neither shrank nor stretched over time. Microstructural data was used with the zero creep loads in a model for grain boundary diffusion controlled creep in multilayers to determine the interfacial free energy.
Mechanical Properties of Ag/Cr Multilayered Epitaxial thin Films
Authors: English Gerald R. , Simenson Glenn F. , Clemens Bruce M. , Nix William D.
Published: April 2011

Metallic multilayer thin film structures exhibit very high hardnesses. The epitaxial Ag/Cr system was chosen to investigate the mechanisms responsible for these high hardnesses. The interfaces of this multilayer structure are expected to be chemically abrupt since silver and chromium are nearly immiscible and do not form intermetallic compounds. The crystallographic structure formed by epitaxial growth isolates the slip systems of each layer.

The samples were deposited on (001) MgO substrates by sputter deposition at room temperature. The bilayer spacing of the samples ranges from 1 nm to 20 nm. X-ray diffraction results indicate that the multilayer films exhibit the rotated (001) crystal structure. Hardness and indentation modulus were measured by depth-sensing indentation experiments using a Nanoindenter. The maximum hardness is roughly four times the weighted average of the single component films. The indentation modulus at small bilayer periods varies by ±15% from the value at large bilayer periods, but all of the values fall between the moduli measured for the single component films.

Decreasing the bilayer period increases the hardness. At bilayer spacings smaller than 4 nm, the hardness remains constant. Decreasing the thickness of the Cr layer while keeping the thickness of the Ag layer at 5 nm, increases the strength of the multilayered film. At Cr thicknesses smaller than 5 nm, the hardness decreases as the Cr thickness decreases. The effect of the volume fraction of Cr on film strength was also studied.

The results are discussed in the context of a deformation model in which the dislocations responsible for deformation are constrained to move in the individual layers. From this model, a lower bound on the strength of the multilayered film can be calculated if plastic deformation occurs in only one layer. An upper bound can be calculated if plastic deformation occurs in both layers. The data fall between the upper and lower bounds and lie closer to the lower bound.
Measurement of the Dependence of Stress and Strain on Crystallographic Orientation in Cu and Al thin Films
Authors: Zielinski E. M. , Vinci R. P. , Bravman J. C.
Published: April 2011

The orientational dependence of stress and strain was measured for (111) and (110) oriented grains in an Al thin film which hillocked upon heating, and (111) and (100) oriented grains in Cu thin films, one of which exhibits abnormal (100) grain growth. Results from the Al thin film were inconclusive in the evaluation of the Sanchez model for hillocking, however they indicate that the Nix model for the orientational dependence of yield stress is not applicable to individual grains at room temperature. Results from the Cu thin films suggest that suppression of (100) abnormal grain growth is due to isostress averaging among the grains of varying orientation.
Stress Relaxation in Al-Si-Cu Thin Films and Lines
Authors: Witvrouw A. , Proost J. , Deweerdt B. , Roussel Ph. , Maex K.
Published: April 2011

Substrate curvature measurements were used to study stress relaxation in Al-Si-Cu films at temperatures between 45 and 165 °C. Dislocation glide with an average activation energy, resp. athermal flow stress of 1.7 ± 0.2 eV, resp. 600 ± 200 MPa could describe the relaxation data for temperatures up to 120 °C well. Stress relaxation at 92 °C was found to progress much slower in 1 μm wide nitride passivated lines than in thin films or unpassivated lines.
The Effect of Intrinsic Passivation Stress on Stress in Encapsulated Interconnect Lines
Authors: Mack Anne Sauter , Flinn Paul
Published: April 2011

The stress in an encapsulated metal line has been calculated using the finite element technique for two passivation stress conditions. It is found that the stress-state in the passivation has a negligible effect on the stress in the metal line. The dominant factors affecting metal line stress are the passivation temperature, the thermal expansion coefficient difference between the metal line and the substrate, and the passivation modulus.
Elastic Properties and Stresses in Polyimide thin Films and Coatings
Authors: Sheth Kapil C. , Chen Michael , Farris Richard J.
Published: April 2011

Polyimide thin films and coatings (< 20μm) for electronic applications have been fully characterized. Analysis of residual stresses and determination of all 21 anisotropic constants are necessary for a better understanding of these coatings in complex geometries. The residual stresses have been measured by a real-time vibrational holographic interferometry technique. The number of elastic constants is reduced to 9 independent constants by finding the orthotopic axes. All the 9 orthotropic constants - 3 normal compliances, 3 shear compliances and 3 independent Poisson’s ratios - have been determined. Moisture diffusion constants have also been measured.
Development of A Technique for the In-Situ Measurement of the Mechanical Properties of Ultra-Thin Interfacially Polymerized Films
Authors: Greenberg Alan R. , Khare Vivek P. , Krantz William B.
Published: April 2011

Crosslinked polyamide barrier layers made by a self-limiting interfacial polymerization (IP) process are extremely thin (= 1000 Å), relatively defect-free and possess excellent perm selective properties which enable their commercial application in thin film composite (TFC) membranes. Little information has been reported in the open literature concerning the physical as well as mechanical properties of these polyamide IP films due to the substantial difficulties in making direct measurements on such thin crosslinked materials. Consequently, the development of IP-TFC membranes for commercial separations has been largely a trial-and-error process.

We are developing a novel experimental technique, Pendant Drop Mechanical Analysis (PDMA) that utilizes the capabilities of the pendant-drop tensiometer for in-situ measurements of the mechanical behavior of the IP films. The current effort focuses on relating the mechanical behavior of the IP films to their structure, which in turn will be related to the permselective performance. Preliminary PDMA results indicate significant differences in the mechanical behavior of the IP films as a function of composition and contact time. These differences can be related to changes in the network characteristics.
Measurements of Elastic Modulus Using Laser-Induced Surface Waves
Authors: Chang D. J. , Amimoto S. T. , Gross R. W. , Glenn T. S.
Published: April 2011

Measurements of the elastic modulus of fused silica, 6061-T6 and 7075-T651 aluminum alloys, GaAs, Ge, and Si samples are reported. A pulsed laser is used to generate surface acoustic waves in a sample and the wave velocity is measured using a knife-edge detection method. From the velocity of the surface waves the elastic modulus can be calculated.[1] Extension of this work to thin films is discusssed.
Photoacoustic Method for Obtaining Strength Characteristics of Thin Films
Authors: Konovalov I. A. , Sklyarenko S. K.
Published: April 2011

Local thermoelastic stresses appear in the surface layers of materials under pulsed laser irradiation. Changes in the amplitude and shape of acoustic signals with laser pulse intensity were studied. Changes corresponding to a transition from purely elastic to elastoplastic deformation in the zone of interaction between the radiation and surface have been registered. Measurement of the absorbed energy radiation which causes these threshold phenomena makes it possible to estimate the yield limit for plastic materials and strength limit for brittle ones.
Studies of Ultra Micro Indented Multilayered Sol-Gel Zirconia Films
Authors: Jômting Å. , Ben-Nissan B. , Ashcroft I. , Swain M. V. , Bell J. M.
Published: April 2011

The deformation behavior of sol-gel derived zirconia films during ultra micro indentation has been investigated. The sol-gel films were deposited using a multiple stage coating procedure onto stainless steel substrates. The indentation process was carried out using both pointed indenters, such as a Berkovich, as well as spherical indenters. The use of different indenter types enables the determination of hardness, elastic modulus as well as the elastic-plastic or elastic-brittle transition of the films. The mechanical behavior of thin films is strongly influenced by the interaction between the substrate and the film. In brittle materials, the stress singularities induced by the indentation process cannot readily be reduced by long range plastic flow and may cause cracking. Therefore, a great deal of attention has been paid to post-indentation observations of the films, in particular examinations of the surface morphology for visible traces of the film behavior during indentation.
A Tem Investigation of the Effects of Tensile Stress on Thin Film Microstructure and Surface Morphology
Authors: Harris Karen E. , King Alexander H.
Published: April 2011

We have studied the microscopic effects of tensile stress on film thickness and grain growth in gold thin films of 25nm nominal thickness using transmission electron microscopy. Free-standing films were annealed at 150°C resulting in films with columnar grains and 〈111〉 fiber texture. After repeated anneals, tensile stresses caused by grain growth became large enough to cause cracks to form and propagate diffusively. While tensile stress must eventually result in an overall decrease in film thickness, local specimen thickening in front of crack tips is observed. The tensile stress also profoundly affected grain growth in these films. Grains near crack tips are larger than grains 400nm away from the tips, and elongated grains with axial ratios greater than 15 have been observed in cracked regions of the films.
Evaluation of the Mechanical Properties of Tribochemical Films on Alumina
Authors: Gee M. G. , Jennett N. M.
Published: April 2011

This paper presents the results of the mechanical characterisation, by a mechanical properties microprobe or nanoindenter, of tribochemical films produced by the sliding wear of alumina in a humid environment.

It was found that the tribochemical films were softer than the remnant alumina on the worn surfaces, and were liable to fracture and cracking under the indenter.
Amorphous Magnetoelastic Materials
Authors: Savage H. T. , Wun-Fogle Marilyn
Published: April 2011

The outstanding feature of amorphous magnetoelastic alloys is the controllability of the magnetic anisotropy energy, Curie point, magnetostriction and magnetic moment. This control of material characteristics, achieved by magnetic and stress annealing plus changes incomposition, is impossible in crystalline materials. The control allows the design of tactile and magnetic field sensors with special features and very high sensitivity. The materials discussed are prepared by rapid solidification through melt spinning in ribbon and wire geometries and magnetron sputtering onto substrates. As an example of the advantagesof sputtered material, an accelerometer on silicon micro-cantilevers is shown. I-t has nocoils. The basic magnetoelastic theory that governs tactile sensors is shown. Low-noise magnetic field sensors with novel twist anisotropies and Barkhausen instabilities in wiresare discussed.
Correlations Between the Bipolar- and Unipolar-Electric Field Induced Strain in Pb(Mg1/3Nb2/3)O3-PbTiO3 Ceramics
Authors: Park Jae-Hwan , Kim Byung-Kook , Park Soon Ja
Published: April 2011

Correlations between the strains induced by a unipolar-electric field and the strains induced by a bipolar-electric field were investigated for Pb(Mg1/3Nb2/3)O3 (PMN) and 0.9{Pb(Mg1/3Nb2/3)O3}-0.1PbTiO3 (0.9PMN- 0.1PT) relaxor ferroelectric ceramics in the temperature range of −50°C ∼ 150°C. The magnitudes of the unipolarly induced-strains are almost the same as the differences between the bipolarly induced-strains and the residual strains, which were attributed to the absence of change of spontaneous polarization direction when the unipolar-electric field is applied.