bluuebunny/crossref_metadata_2025_split huggingface dataset:
Yield Improvement via minimization of step height non-uniformity in Chemical Mechanical Planarization (CMP)
Authors: Kadavasal Muthukkumar , Eamkajornsiri Sutee , Chandra Abhijit , Bastawros Ashraf F. 
Published: June 2019

AbstractObtaining local and global planarity is one of the prime criteria in dielectric and metal planarizations. Although Chemical Mechanical Planarization (CMP) helps us achieve this criterion in constant pattern density surfaces, the same is not true for variable pattern density surfaces this results in formation of global step heights across the die. This paper provides a pressure open loop control algorithms for obtaining planarity across a die containing variations in pattern densities. Based on the variation of pattern density and surface heights across the die, the surfaces are separated into zones and the pressure is varied spatially and/or temporally to obtain uniform surface heights, with enhanced step height uniformity. One of the algorithms looks ahead and recalculates/modifies the pressure values by identifying the step heights that could be formed after a specified time step. The final surface predictions have improved uniformity on the upper surface as well as on the step heights across the entire die. The simulation would help us track the polishing process for each time step and guide us with the optimized pressure values that can be applied in order to an uniform final surface evolution.
Polishing Slurries with Aluminate-modified Colloidal Silica Abrasive
Authors: Belov Irina , Kim Joo-Yun , Watkins Paula , Perry Martin , Pierce Keith 
Published: June 2019

AbstractThis study has developed a route for increasing stability of colloidal silica particles in acidic polishing slurries. Drastic improvement in colloid stability has been achieved by using SiO2 particles with increased negative surface charge through doping/modification with metallate ions Me(OH)4–, particularly with aluminate ions. Novel Copper CMP slurries employing aluminate-doped colloidal silica provide high removal rates, good planarization and dishing performance, demonstrate required stability and long shelf life while preserving all the morphological advantages of colloidal abrasive particles. The developed route is also useful for production of acidic polishing slurries for other applications, such as Tungsten and STI CMP, as well as in polishing hard drive disks, fiber optic connectors, etc.
Characterization of the Chemical Effects of Ceria Slurries for Chemical Mechanical Polishing
Authors: Abiade J. T. , Yeruva S. , Moudgil B. , Kumar D. , Singh R. K. 
Published: June 2019

AbstractFor highly selective particle-based slurries or fixed abrasive pads, ceria has been identified as the abrasive of choice for the chemical mechanical polishing (CMP) step for shallow trench isolation (STI). The advantageous performance of ceria-based CMP consumables is usually attributed to enhanced chemical reactivity between ceria and oxide materials. In fact, this reaction is a central theme of all ceria polishing models from glass polishing to STI CMP. Previously, experimental evidence in support of the ceria-silica reaction during CMP was virtually non-existent. Recently, we proposed a pH-dependent ceria-silica polishing mechanism based on polishing results, in-situ friction force measurements, and spectroscopic and microscopic investigations. In this report, we have studied the chemical interactions between ceria and silica in the absence of particles using an atomic force microscope (AFM) and a scanning electron microscope (SEM). AFM silicon tapping mode cantilevers were functionalized by depositing a silica coating via chemical vapor deposition (CVD) and thermal oxidation. SEM imaging and compositional analysis was conducted on the cantilevers before and after wear against a ceria thin film, which was grown by pulsed laser deposition. The cantilever wear profile and elemental composition as a function of pH confirms our earlier polishing results and the pH-dependent CMP model for ceria-silica CMP.
In-situ Metrology for End Point Detection during Chemical Mechanical Polishing of Shallow Trench Isolation Structure
Authors: Zantye Parshuram B. , Mudhivarthi S. , Kumar Ashok , Evans David 
Published: June 2019

AbstractEfficient end point detection (EPD) helps prevent numerous Chemical Mechanical Polishing (CMP) process defects such as dishing, erosion, excessive over-polish etc. During the CMP of Shallow Trench Isolation (STI) structures, the process should be effectively stopped at the buried Si3N4 layer to prevent any/all of the aforementioned process defects. In this research, novel in-situ metrology technique that used the real time tracking of Coefficient of Friction (COF) data during polishing was employed for EPD during STI-CMP. The experiments were performed on the CETR CP-4 CMP Tester using 1“X 1” sample coupons having a 2 ‘mu;m pitch STI pattern. The COF signal during polishing is a characteristic signature of the given process parameters and conditions. The in-situ EPD was based on the principle that the COF values are strongly dependent upon the surface of the materials that are being polished. Extended polishing to polish the underlying layer after the process end point was reached, can give an estimate of the polishing slurry selectivity with respect to the buried layer. The ex-situ surface characterization of coupons was performed at different points of the process using Atomic Force Microscopy (AFM). The repeatability and reliability of this technique was evaluated after carrying out multiple tests at similar process conditions. The demonstrated methodology can also be implemented for characterization of polishing pads and slurries besides STI-CMP process optimization.
High Planarization Efficiency and Wide Process Window Using Electro-chemical Mechanical Planarization (EcmpTM)
Authors: Liu Feng Q , Chen Liang , Duboust Alain , Tsai Stan , Manens Antoine , Wang Yan , Hsu Wei-Yung 
Published: June 2019

AbstractEcmpTM is a revolutionary planarization technology uniquely combining removal rate controlled by charge with superior planarization efficiency in the near no shear regime. In addition, the electrochemical removal mechanism has excellent within-wafer profile control. Multiple electrical zones configuration combined with a precise end-point control by electric charge, make it more predictable to control the remaining thickness and profile of copper film. The factors affecting the planarization such as the concentration and the efficiency of the inhibitors will be discussed in this paper. Meanwhile a planarization mechanism for Ecmp will be proposed to match the high planarization efficiency. The effects of applied voltage on removal rate and planarization efficiency will be presented in this paper. The electrical feature allows Ecmp to be a planarization process with removal rate independent of down force, enabling a wide removal rate window based on applied voltage.
Influence of the Substrate Temperature on the Texture of MgO Films Grown by Ion Beam Assisted Deposition
Authors: Stan Liliana , Arendt Paul N. , DePaula Raymond F. , Usov Igor , Groves James R. 
Published: June 2019

AbstractThe variation in the substrate temperature during ion beam assisted deposition (IBAD), which employs the use of energetic ions to bombard a growing film, has been shown to influence the quality of crystalline texture in MgO films. Determining the acceptable deviation from the optimum ion to molecule ratio for different substrate temperatures establishes the optimum MgO deposition conditions. For each fixed deposition temperature, a set of samples was produced by varying the ion assist beam current from sample to sample while keeping the deposition rate constant. In this way, the ion to molecule ratio was modified and the range of achieving well textured films was determined. The investigation of the MgO texture dependence on the substrate temperature reveals that the best in-plane alignment is obtained at ˜ 25°C. At this temperature, MgO films with in-plane orientation distribution as low as 3.7° full width at half maximum (FWHM) have been attained. MgO films deposited at temperatures higher than 100°C have broad in-plane alignment. Although, the deposition at the lowest temperature (-150°C) did not improve the in-plane texture, the acceptable deviation from the optimum ion to molecule ratio for achieving biaxially textured films was the largest. As a trend, the acceptable ion to molecule deviation decreases with increasing substrate temperature. This is especially important for continuous IBAD MgO depositions where less restrictive conditions are desired.
Development of Electrodeposited Iridium as a Buffer Layer for YBCO Superconductors
Authors: Spagnol Priscila , Chaudhuri Tapas , Bhattacharya Raghu , Phok Sovannary 
Published: June 2019

AbstractElectrodeposition (ED) is a potentially low-cost, non-vacuum, high-rate deposition process that can easily deposit uniform film on large non-planar substrates. In this paper, we report on successful biaxial textured electrodeposition of Ir on Ni-W substrates. Ir metal is well known for its excellent oxidation and corrosion resistance among platinumgroup elements; also, the lattice mismatch of cubic Ir is very close to that of CeO2 and Ni. The films were deposited in a vertical cell in which the electrodes (both working and counter) were suspended vertically from the top of the cell. The ED experiments were performed at 65°C without stirring the solution. The ED precursors were prepared at about -1.2 V from 2 to 15 minutes on Ni-W, where the Pt counter and Pt pseudo-reference electrodes were shorted together. To qualify the electrodeposited Ir buffer layer, a CeO2/YSZ/CeO2 and YSZ/CeO2 buffer structure was later deposited on ED Ir-coated Ni-W substrates by pulsed-laser deposition. The ED Ir/metal substrates were first heated at 800°C in 0.5 mTorr of forming gas, and then a CeO2 seed layer was deposited in 180 mTorr of forming gas. Subsequently, YSZ and CeO2 layers were deposited sequentially in 0.1 mTorr of oxygen.
Superconducting YBCO Films Prepared by Electrodeposition and Spray Pyrolysis
Authors: Phok S. , Spagnol P.D. , Chaudhuri T. , Bhattacharya R.N. 
Published: June 2019

AbstractBiaxially textured YBa2Cu307-δ films were fabricated by non-vacuum electrodeposition and spray pyrolysis techniques. Electrodeposited YBCO was prepared on sputtered copper/single-crystal substrates. Electrodeposition was carried out at constant voltage and the deposition was completed in only few minutes. The thickness of the as-deposited films was in the range of 0.6 to 2 μm. The optimized sputtered copper layer thickness was about 200 Å on SrTiO3. In the spray pyrolysis method, the solution is sprayed directly onto SrTiO3 substrates. The substrate temperature is about 100°C. The thickness of the as-deposited films was in the range of 1.2 to 2μm. The electrodeposited and spray-deposited films were annealed at temperatures ranging from 800° to 920°C under various flowing gas mixtures. X-ray diffraction analysis revealed that processed electrodeposited and spray-deposited films were biaxially textured, where YBCO grains were well oriented along the c-axis and in the (a,b) plane. Δω, deduced from the rocking curve on the (005) reflection, was as low as 0.46°. Δφ, deduced from the phi-scan on the (103) reflection, was as low as 0.54°. The critical current density for these types of films is about 0.5 MA/cm2at 77 K and 0 T.
High-Performance Low Voltage Organic Thin-Film Transistors
Authors: Vusser Stijn De , Steudel Soeren , Myny Kris , Genoe Jan , Heremans Paul 
Published: June 2019

AbstractIn this work, we report on high-performance low voltage pentacene Organic Thin-Film Transistors (OTFT's) and circuits. Inverters and ring oscillators have been designed and fabricated. At 15 V supply voltage, we have observed invertors showing a voltage gain of 9 and an output swing of more than 13 V. As for the ring oscillators, oscillations started at supply voltages as low as 8.5 V. At a supply voltage of only 15 V, a stage delay time of 3.3 νs is calculated from experimental results.We believe that these results show for the first time a high speed ring oscillator at relatively low supply voltages. The required supply voltages can be obtained by rectification using an organic (pentacene) diode. These results may have an important impact on the realization of RF-ID tags: by integrating our circuits with an organic diode, the fabrication of organic RF-ID tags comes closer.
Electrical Characterization of Transmission Lines on Nonwoven Textile Substrates
Authors: Merritt Carey R. , Karaguze Burcak , Kang Tae-Ho , Wilson John M. , Franzon Paul D. , Nagle H. Troy , Pourdeyhimi Behnam , Grant Edward 
Published: June 2019

AbstractThe focus of this paper is the electrical characterization of coplanar waveguide (CPW) transmission lines that are printed onto nonwoven textile substrates using conductive inks, to determine their suitability for wide-band applications, e.g. digital signaling. The conductive ink line characterization tests included the defining of DC and Time-Domain Reflectometry metrics. The transmission line test samples were screen printed onto two different types of nonwoven textile substrates using two different conductive inks, i.e. inks with different viscosities. Tests showed that the variations in the continuity of the transmission lines varied, giving rise to geometrical variations in the CPW structure; and in the characterization of the same.
Nanoindentation and Finite Element Analysis of Resin-Embedded Bone Samples as a Three-Phase Composite Material
Authors: L. Oyen Michelle , Ko Ching-Chang , K.Bembey Amanpreet , Bushby Andrew J. , Boyde Alan 
Published: June 2019

AbstractThe effective elastic modulus of composite materials results from a combination of elastic moduli of the component phases. Recent efforts to understand the mechanical behavior of calcified tissues in bones and teeth require estimates of the component phase properties, which are difficult to establish independently. A three-phase system, based on naturally occurring bone, is therefore examined by a combined nanoindentation and finite element modelling approach to better understand the proportions and properties of the component phases. Bone samples were prepared in four two- or three-phase composite configurations as follows: (1) as a dehydrated mineral-protein composite (with some void space); (2) similarly dehydrated mineral-protein composite but with polymethylmethacrylate (PMMA) resin filling the voids resulting in three solid phases; (3) as a PMMA-mineral composite following protein removal and replacement with PMMA, and (4) as a PMMA-protein composite following mineral removal and replacement with PMMA. Effective component volume fractions and elastic moduli for each phase in each system were computed based on the composite nanoindentation results. Finite element models of the two- and three-phase systems were constructed to explore the structural anisotropy of the composite systems, as demonstrated in the nanoindentation tests, and to examine the sensitivity of the composite results to changes in the assumed component properties.
AFM Imaging of Water, Cells and Tissues
Authors: Li Xiaodong 
Published: June 2019

AbstractThis paper presents the results of several AFM case studies of water, tumor cells, pit cells, and type-I collagen samples. The AFM imaging procedures, surface structural characterization capabilities such as contact mode, tapping mode, and friction mode are discussed. The difference in surface morphology between the pit cell submerged in liquid and the cell in air was observed. The AFM tapping mode phase imaging technique was used to study the crosslinks in the type-I collagen. The calibration method for accurately measuring the AFM cantilever spring constant with the help of a nanoindenter is also presented.
Viscoelastic Models Describing Stress Relaxation and Creep in Soft Tissues
Authors: Kobelev Alexa V. , Kobeleva Rimma M. , Protsenko Yuri L. , Berman Irina V. , Kobelev Oleg A. 
Published: June 2019

AbstractThe review of our approach to the specific rheological properties modeling of myocardium has been given. We are working on the level of ‘fascicule’ as a tissue element, which consists of several cardiomyocytes surrounded by a connective tissue shell. Actually, these properties are characteristic of large majority of living soft tissues. In order to describe essentially nonlinear static ‘force-deformation’ curves and quasi-static hysteresis loops together with non-exponential stress relaxation and creep time courses we suggest a set of 2D graphs with different topology composed of classical linear Hook's springs and Newtonian damps. Each spring and dashpot represents a group of 3D tissue structural elements. The stress response functions of these models are found for the uniaxial step-wise, or pulse (column-like) external stretching. The inverse response functions of the longitudinal displacement for the external stress loading of the pulse shape time dependencies were also found. The values of elastic modules and viscous coefficients are estimated by comparison theoretical curves of relaxation, creep and recovery with the experimental data. The latter are obtained on rather different objects, passive muscle preparations (the stress relaxation response) and endothelium cells (the creep response). It has been stated that the proposed 2D models appear to be quite general to describe nonlinear relaxation and creep properties, which are lacking in the traditionally used uniaxial 1D models.
Structural Distinctions Between Biogenic and Geological Aragonite
Authors: Pokroy Boaz , Quintana John P. , Zolotoyabko Emil 
Published: June 2019

AbstractEnergy-variable synchrotron x-ray diffraction was applied to probe local structure in different kinds of aragonitic seashells with spatial resolution. All investigated specimens revealed lattice distortions of biogenic aragonite with respect to the geological mineral. The obtained data are analyzed in terms of residual strains induced by intercalating organic macromolecules.
First Principles Study of Size Effect in BaTiO3 Ultrathin Films
Authors: Lai Bo-Kuai , Kornev Igor , Bellaiche Laurent , Salamo Greg 
Published: June 2019

AbstractProperties and phase transition behaviors of ferroelectric thin films that are different from that of their bulk form is usually referred to as size effect. A first-principles-based scheme is used to investigate the effects of four important factors contributing to the size effects in epitaxial (001) BaTiO3 ultrathin films: misfit strain, existence of surface, film thickness, and electrical boundary conditions.
Effective Direct Piezoelectric Constants in Epitaxial Ferroelectric Films as MEMS Sensors
Authors: Ouyang Jun , Ramesh R. , Roytburd A. L. 
Published: June 2019

AbstractFollowing our previous work on the converse piezoelectric constant- in epitaxial ferroelectric films for MEMS actuator applications, the orientation dependence of the direct piezoelectric constants , and are generally formulated, which can help to predict and optimize the performance of piezoelectric MEMS sensor devices based on ferroelectric thin films. Numerical results are obtained and discussed for Pb(ZrxTi1-x)O3 thin films grow on Si substrates with various compositions and structures.
Magnetoelectric Laminate Composites – Enhanced Magnetic Field Sensitivity, and High Voltage Gain
Authors: Dong Shuxiang , Zhai Junyi , Xing Zhengping , Li Jie-Fang , Viehland D. 
Published: June 2019

AbstractIn this paper, the magnetoelectric (ME) coupling and working modes are defined and discussed. Several types of ME laminate composites based on Terfenol-D, Fe-Ga magnetostrictive layers and piezoelectric Pb(Mg1/3Nb2/3)O3-PbTiO3 crystal, Pb(Zr,Ti)O3 ceramic layers have been developed. Our experiments confirm that these ME composites have giant magnetoelectric voltage coefficients of ∼0.43×103 mV/Oe in the frequency range of 10-2<f<104 Hz under low magnetic bias. When operated under resonant conditions, the ME voltage coefficient is dramatically enhanced to maximum values as high as ∼20×103 mV/Oe. At resonance, our ME laminates have (i) a strong voltage gain effect; and (ii) an ultrahigh magnetic field sensitivity of near 10-12 Tesla.
Beyond Weight Percent - The Influence of Material Characteristics on Hydrogen Storage System Performance
Authors: Mosher Daniel A. , Anton Donald L. 
Published: June 2019

AbstractThe attribute of solid state hydrogen storage materials that is most commonly the focus of evaluations is reversible hydrogen weight percent. Other material characteristics, including density, charging pressure, enthalpy and conductivity can influence the weight of storage system components and hence the overall hydrogen weight percent that is ultimately of interest. However, accounting for these effects involves some level of storage system representation that typically is not undertaken when making material assessments and comparisons.The current paper will present a simple model that represents system elements and trade-offs on a high level so that overall system performance can be estimated without the burden of detailed design studies. The model should be useful to evaluate novel materials in a more complete manner for a better assessment of their potential when implemented in a storage system. While the model has been derived based on the design of a particular NaAlH4 system, the key attributes are sufficiently general to be applicable to a range of system designs. Using this approach, the properties of materials can be related more precisely to goals for overall system performance with modest additional effort.
Effect of Carbon Addition on Hydrogen Storage Performances of Magnesium-based Alloys: from Bulk Powders to Thin Films
Authors: Rougier A. , Darok X. , Bhat V.V. , Aymard L. , Nazri G.A. , Tarascon J.-M. 
Published: June 2019

AbstractMg-based thin films were successfully grown by Pulsed Laser Deposition. Dramatic optical changes were observed depending on the conditions of deposition. Films grown in vacuum were shiny metallic whereas the ones grown in a Ar/H2 gas mixture were highly transparent. Ex situ hydrogenation, by annealing the films at 200 °C in 15 bars of hydrogen, led to similar metallictransparent transformation. Mg-Cx (x ≤ 20 %) films show a faster hydrogenation associated with a significant decrease in oxygen content by carbon addition.
Development of Hydrogen Absorbing Alloy with High Dissociation Pressure
Authors: Kojima Yoshitsugu , Kawai Yasuaki , Towata Shin-Ichi , Matsunaga Tomoya , Shinozawa Tamio , Kimbara Masahiko 
Published: June 2019

AbstractThe effective hydrogen capacity of TixCr2-yMny [≫X λ1.1 (1.08≤0x≤1.16), y λ1.0 (0.96≤y≤1.08)rsqb; exhibited the maximum value of 1.8 wt% in the pressure range of 33 MPa and 0.1 MPa at 296K (dissociation pressure: 5-11 MPa), and the alloy provided over 10% more capacity than conventional Ti-Cr-Mn (Ti1.2CrMn: 1.6 wt%, Ti1.2Cr1.9Mn0.1: 1.3 wt%). At the low temperature of 233 K, the alloy absorbed 2.0 wt% of hydrogen and the hydrogen desorption capacity at 0.1 MPa was 1.6 wt%. The dissociation pressure decreased with the Ti and the Mn contents and was explained by the function of the bulk modulus and the cell volume. According to the van't Hoff plots, the standard enthalpy differences (heat of formation) of the Ti1.16Cr0.92Mn1.08 and Ti1.08Cr1.04Mn0.96 hydrides were -21 and -22 kJ/molH2, respectively. These absolute values were about 10 kJ/molH2 smaller than those of LaNi5 and Ti-Cr-V. The alloy had sufficient hydriding and dehydriding kinetics. In the pressure range of 33 MPa and 0.1 MPa at 296 K, the alloy absorbed and desorbed 1.8 wt% of hydrogen in 60 sec and 300 sec, respectively. The hydrogen capacity changed gradually over many cycles and that after 1000 cycles was 94 % of the initial capacity. Thus Ti1.1CrMn can be utilized for a high- pressure MH tank which contains a hydrogen absorbing alloy with high dissociation pressure and compressed hydrogen.