bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oriented Polymer/Metal Nanocomposites: A New Method for the Production of Polarization Dependent Color Filters
Authors: Dirix Yvo , Bastiaansen Cees , Caseri Walter , Smith Paul 
Published: April 2011

ABSTRACTUniaxially oriented composites of high-density polyethylene and silver nanoparticles were prepared using solution-casting, melt-extrusion and solid-state drawing techniques. The absorption spectrum in the visible wavelength range of the drawn nanocomposites was observed to strongly depend on the polarization direction of the incident light. For instance, the nanocomposites appear bright yellow or red when the vibration direction of linearly polarized light is perpendicular or parallel, respectively, to the drawing axis. The optical anisotropy of the drawn nanocomposites originates from uniaxially oriented, pearl-necklace type of arrays of nanoparticles of high aspect ratios. The absorption spectrum of the nanocomposites can be shifted to higher wavelengths using appropriate annealing procedures. The annealing results in an increased size of the primary silver particles, due to Ostwald ripening, and consequently a range of polarization-dependent colors can be generated in the drawn nanocomposites. It is suggested that the drawn nanocomposite films can be used in liquid crystal displays (LCD's) were they serve a dual purpose in combining polarization filter and color filter. The new display configuration transmits colored light in both the on- and off-state of the device, this in contrast to a conventional color LCD which only transmits colored light in the off-state. As a consequence, an enhanced brightness and light (energy) efficiency of the new display set-up is envisioned.
The Dynamic Properties of 5Cb Filled with Aerosil Particles Investigated by Pcs
Authors: Aliev F.M. , Kreuzer M. , Panarin Yu.P. 
Published: April 2011

ABSTRACTNematic liquid crystal filled with Aerosil particles, a prospective composite material for optoelectronic application, has been investigated by static light scattering and Photon Correlation Spectroscopy (PCS). The Aerosil particles in filled nematic liquid crystals (FN) form a network structure with LC domains about 2500 Å in size with a random distribution of the director orientation of each domain.We found that the properties of 5CB are considerably affected by the network. The N-I phase transition in filled 5CB was found to be smeared out and depressed. PCS experiments show that two new relaxation processes appear in filled 5CB in addition to the director fluctuation process in bulk. The slow relaxation process, with a broad spectrum of relaxation times, is somewhat similar to the slow decay, which is observed in confined nematic liquid crystal.The middle frequency process was assigned to the director fluctuations in the surface layer formed at the particle-LC interface. The decay function describing this relaxation process is a stretched exponential (β ≍ 0.7). The temperature dependence of the relaxation times of the middle frequency obeys the Vogel-Rilcher law. Such a temperature dependence, accompanied by a broad spectrum of relaxation times suggests that the dynamics of the director fluctuations near the Aerosil particle-LC interface is glass-like.
Electroplated Damascene Copper: Process Influences on Recrystallization and Texture
Authors: Gross M. E. , Drese R. , Lingk C. , Brown W. L. , Evans-Lutterodt K. , Barr D. , Golovin D. , Ritzdorf T. , Turner J. , Graham L. 
Published: April 2011

ABSTRACTElectroplated Cu films undergo a remarkable recrystallization at room temperature that has been associated with dislocations and defects arising from the influence of surface-active additives during plating. In the process of plating, the composition of the bath changes as the organic additives are depleted by incorporation into the Cu films or electrolytic decomposition and replenished by fresh additions. Given the sensitivity of the plating process to low concentrations of additives, the properties of the plated Cu might be expected to differ between a freshly prepared bath and an older bath that has processed thousands of wafers and achieved a steady state composition of additives and by-products.In this paper we compare the recrystallization rates of Cu films deposited from two such baths on wafers with damascene trenches of widths from 0.3 to 5 μm. Films deposited from the older bath consistently recrystallize at a faster rate for all trench widths and both barrier materials (Ta, TaN) studied. The concentration of impurities is comparable in the two films. Therefore, the difference in rates is likely due to a difference in defect densities in the film due to different adsorbate/surface interactions during plating. Although the recrystallization rates vary, X-ray diffraction pole figure analysis of films plated from the two baths show no differences in texture. Sidewall growth components are visible in both sets of samples. Data on the influence of the barrier material and trench width on recrystallization rates are also presented.
A Study On High Coercivity And Lio Ordered Phase In Copt And Fept Thin Films
Authors: Ristau R. A. , Barmak K. , Lewis L. H. , Coffey K. R. , Howard J. K. 
Published: April 2011

ABSTRACTThis study relates the microstructure of equiatomic binary alloys of CoPt and FePt with their room-temperature hysteretic magnetic properties, particularly their high coercivity. A transformation from an atomically disordered, face-centered-cubic structure to the Li0ordered structure occurred during post-deposition annealing and was characterized using digital analysis of dark-field transmission electron microscopy (TEM) images. The transformation was observed to follow first-order nucleation and growth kinetics, and the ordered volume fraction transformed was quantified at numerous points during the transformation. The ordered volume fraction was then compared to the magnetic coercivity data obtained from a superconducting quantum interference device (SQUID) magnetometer. Although the relationship most commonly described in the literature is that the highest coercivity corresponds to a two phase ordered/disordered mixture, the maximum value for coercivity in this study was found to correspond to the fully ordered state. Furthermore, in samples that were less than fully ordered, a direct relationship between ordered volume fraction and coercivity was observed. The proposed mechanism for the high coercivity in these films is an increasing density of magnetic domain wall pinning sites concurrent with an increasing fraction of ordered phase.
Magnetic Anisotropy in La0.7(Sr,Ca)0.3MnO3 Epitaxial Thin Films And Crystals
Authors: Steenbeck K. , Hiergeist R. , Revcolevschi A. , Pinsard-Gaudart L. 
Published: April 2011

ABSTRACTThe biaxial and uniaxial magnetic anisotropies of epitaxial { 100} oriented La0.7(Sr,Ca)0.3MnO3 films on different substrates and of a sphere-shaped single crystal were measured by torque magnetometry at temperatures ranging from T = 20K to room temperature. In the films the biaxial anisotropy with easy axes <110= dominates and is described by a cubic crystal anisotropy constant ranging up to K1 ≈−104J/m3. The uniaxial anisotropy was |Ku| ≤ 103 J/m3 and is explained by anisotropic stress. In the single crystal the main anisotropy is uniaxial with a hard axis parallel to [ 111], and with an anisotropy constant KR up to 104J/m3. KR was measured in different planes and explained by the rhombohedral lattice distortion. The biaxial anisotropy in the crystal (K1 = −103 J/m3 at T = lOOK) was smaller than in the films. Differences between film and single crystalline behaviour are discussed in terms of crystal structure and lattice constriction.
Growth of Thin SiO2 bY “SPIKE” Rapid Thermal Oxidation
Authors: Fiory A. T. 
Published: April 2011

ABSTRACTWafers prepared with HF and RCA cleaning were oxidized at atmospheric pressure O2 with an incandescent-lamp processor using temperature ramping at rates up to 150°C/s for heating and 80°C/s for cooling. The minimum oxidation time obtained by the “spike” method of turning off lamp power prior to reaching a desired peak temperature is effectively 2s. Film thickness for spike oxidation ranges from about 1.6 nm for peak temperature of 1000°C to about 2.2 nm for peak temperature of 1100°C. Activation energies of 2.5 eV are determined for 1.5 – 4 nm films. Films grown for varied times and temperatures to produce equal oxide thickness, as measured by ellipsometry, show nearly equivalent physical properties in measurements by corona-charge and Kelvin probe surface photovoltage techniques.
Fowler-Nordheim Tunneling Current Oscillation Study of Interface Roughness
Authors: Lai L. , Irene E.A. 
Published: April 2011

ABSTRACTA decrease in the amplitude of Fowler-Nordheim current oscillations (FN-CO) due to interface roughness is observed for thin film (∼40Å) metal-oxide-semiconductor (MOS) devices, only when the interface has high spatial complexity. Previous studies have shown no measurable changes in FN-CO's resulting from the oxidation of purposely roughened Si surfaces. The present research continues with an FN-CO study using Si surfaces with roughness of higher spatial complexity than the previous studies. The spatial complexity of the purposely roughened Si surfaces was compared using the fractal dimension (DF). Atomic force microscopy (AFM) was used to measure the interface topography, and fractal dimension (DF) was used to describe the surface complexity while root-mean-square (RMS) roughness was used for obtaining vertical information of the roughness. It was found that the oscillation amplitude decrease substantially with an increase of DF but with no dependence on RMS.
Enhanced Reliability of Thin Silicon Dioxide Grown on Nitrogen-Implanted Silicon
Authors: Kurinec S. K. , Jackson M. A. , Capasso K. C. , Zhuang K. , Braunstein G. 
Published: April 2011

ABSTRACTThin oxides (3-20 nm) have been grown on nitrogen-implanted silicon by regular thermal oxidation and by rapid thermal oxidation in dry oxygen. The implant dose ranged from 1×1013 to 1×1015 cm−2. Significant oxidation retardation has been observed for nitrogen doses above 1×1014 cm−2. Al-gate MOS capacitors were fabricated to characterize the thin oxides for dielectric breakdown strength and leakage. Gate oxides, grown by our standard baseline process, exhibited a decrease in their dielectric strength from ∼10 MV/cm for thickness > 18 nm to 3-4 MV/cm for < 8 nm thickness. The nitrided oxides maintained their integrity at ∼10 MV/cm as thickness decreased, unless a critical dose was exceeded, which resulted in poor performance. These electrical measurements indicate that a nitrogen implant, prior to gate oxide growth, is beneficial to oxide integrity.The structure of the SiO2/Si interface has been probed using X-ray photoelectron spectroscopy (XPS) and analyzing Si 2p core level spectra. The XPS analyses on as grown samples of nitrided and un-nitrided oxides of similar thickness (3 nm) do not show any significant suboxide peaks corresponding to Si1+, Si2+ or Si3+ states at the interface. However, on exposing the surface to argon ion sputtering at 3.5 kV for 30 seconds, prior to XPS analysis, the presence of suboxides at the SiO2/Si interface is detected. The SiO suboxide (Si2+) density in oxides grown on nitrogen-implanted silicon is much less than that in the oxides grown on unimplanted silicon. This is a direct evidence of sputter damage resistance of nitrided thin oxides. The beam-induced damage in the oxide is also found to be less in nitrided oxides. The suppression of suboxide formation at the interface due to the presence of nitrogen appears to be responsible for the enhanced reliability of nitrided oxides.
Self-control Phenomenon for Crystallinity and Morphology Observed at Epitaxial Growth of BaTiO3 by Alternating Deposition Method
Authors: Shimoyama K. , Kanda T. , Iida M. , Maeda T. , Yamabe K. 
Published: April 2011

ABSTRACTWe directly observed self-control crystallization of epitaxial BaTiO3 films during alternate depositions of BaO and TiO2. When TiO2 (or BaO) was supplied excessively, surface crystallinity and smoothness degraded due to three-dimensional (3D) growth. However, when the following BaO (or TiO2) was supplied onto the rough TiO2 (or BaO) surface, the surface smoothness was recovered drastically. It was found that a single phase BaTiO3 film grew by repeating the alternate deposition cycle of excessive supply of both BaO and TiO2. The mechanism of this phenomenon was discussed.
Study of Thermal Stability of Cvd Ta205/Si Interface
Authors: Mao A. Y. , Son K. A. , White J. M. , Kwong D. L. , Roberts D. A. , Vrtis R. N. 
Published: April 2011

ABSTRACTThe effects of vacuum and inert gas annealing of ultra-thin (20Å) CVD Ta2O5 films deposited on Si substrates, with and without oxynitride interface layer, on the Ta2O5/Si interface stability were examined extensively by means of in-situ X-ray Photoelectron Spectroscopy (XPS), ex-situ Time-of-Flight Secondary Ion mass Spectrometry (ToF-SIMS), and Temperature Programmed Reaction (TPR). When annealed to 680 °C for up to 50 min, changes in ∼ 20Å Ta2O5 films formed on Si(100) are negligible, but annealing to 820 °C for 10 min in vacuum, Ar or N2 produces major chemical restructuring. SiO is formed at the Ta2O5 - Si(100) interfaces and becomes incorporated into the tantalum oxide. A reduced form of Ta, attributed to TaSix, forms at the buried interface. Extending the annealing time to 20 min produces no further changes. SiO desorbs during annealing at 1000 °C. Nitriding Si prior to forming the Ta2O5 film deposition inhibits these processes.
Characterisation of Process Variables for Ultraviolet Assisted Injection Liquid Source Chemical Vapour Deposition (Uvils-Cvd) of Tantalum Pentoxide Films
Authors: Beechinor J.T. , Mooney M.B. , Kelly P.V. , Crean G.M. , Zhang J.-Y. , Boyd I.W. , Paillous M. , Jimenez C. , Stnateur J.-P. 
Published: April 2011

ABSTRACTThe characterisation of the physical and chemical properties of tantalum pentoxide (Ta2O5) films, deposited on silicon using a newly developed low temperature deposition technique - ultraviolet assisted injection liquid source chemical vapour deposition (UVILSCVD), is reported. The effect of deposition parameters including substrate temperature, oxidising agent (N2O) flow, precursor carrier gas (Ar) flow, number of drops of precursor injected and precursor solution concentration is discussed. Spectroscopic ellipsometry (SE) was used to determine the refractive index and thickness of the Ta2O5films. The film thickness was observed to increase with temperature, number of injected drops and precursor solution percentage, while the refractive index was found to be most sensitive to temperature. SIMS measurements showed good agreement with extracted thickness values. Fourier transform infrared spectroscopy was used to identify and monitor Ta2O5(pentoxide), TaO2and TaO (suboxide) formation via curve fitting analysis of spectral features. Results showed increased suboxide formation as a function of increasing pressure and as a function of decreasing N2O flow, precursor solution concentration and number of drops injected. The summation of the areas under peaks characteristic of the tantalum-oxygen bonding correlated well with the thicknesses determined by spectroscopic ellipsometry. The FTIR spectra revealed a dramatic increase in the proportion of suboxide in the absence of the oxidising gas.
High-k Dielectrics and Dual Metal Gates: Integration Issues for New CMOS Materials
Authors: Claflin B. , Flock K. , Lucovsky G. 
Published: April 2011

ABSTRACTSeveral metal and conducting metal nitride candidates were investigated for alternative gate electrode applications in future complimentary metal-oxide-semiconductor (CMOS) devices. High frequency capacitance-voltage (CV) measurements were performed on n-MOS and p-MOS capacitors with Al, Ta, TaN, TIN, or W2N gates and ultra-thin SiO2/Si3N4 dielectric stacks. The work functions of Al and Ta were close to the conduction band of Si as expected while all the metal nitrides had work functions slightly above mid-gap. The thermal stability of the metal nitrides and the metal/dielectric interfaces was studied by Auger electron spectroscopy (AES) following rapid thermal annealing (RTA). Integration requirements for dual metal gate electrodes in future CMOS devices are discussed.
Atomistic Simulations of Damage Evolution in Silicon
Authors: Buneat Marius M. , Fastenko Pavel , Dunham Scott T. 
Published: April 2011

ABSTRACTWe have studied the damage annealing process using kinetic lattice Monte Carlo (KLMC) and molecular dynamics (MD) with initial damage distribution from Monte Carlo ion implant simulations. MD calculations find a long range interstitial vacancy interaction, as also seen in previous tight-binding molecular dynamics (TBMD) simulations.1 The influence of the long range interaction as well as the initial spatial correlations present in the implant damage are then analyzed with KLMC in the form of corrections to the +1 model. We find that both long range interactions and the initial spatial correlations are significant at low doses, while the effects disappear at high doses.
Sub-Nm Screening Layer Approach for Ultra Shallow Junction Formation
Authors: Hori M. , Miyake T. , Hikazutani K. , Kataoka Y. , Nakamura M. , Wada T. , Kase M. 
Published: April 2011

ABSTRACTThis paper describes the influence of the sub-nm screening and capping oxide layer of wet process on B diffusion for 50 nm shallow junction formation. The reason is proposed that the knock-on oxygen into Si makes B diffusion faster such as in the case of oxidation enhanced diffusion. To suppress the B enhanced diffusion, the screening oxide formed before implant should be thin to reduce the knock-on oxygen. The wet process before annealing strongly influences the B diffusion, in particular, thicker capping oxide with sub-oxide structure and knock-on oxygen has an important rule for the enhanced diffusion.
Effect of the oxidation of a silicide layer on dopant diffusion in the underlying silicon
Authors: Kappius L. , Tyagi A. K. , Breuer U. , Bay H. L. , Manti S. 
Published: April 2011

ABSTRACTWe have studied the influence of an epitaxial silicide layer on the diffusion of B and Sb in silicon. B and Sb doping superlattices have been grown by molecular beam epitaxy. They were then covered with a 20 nm thick CoSi2 layer. Test samples were also grown without silicide. Samples were oxidized at various temperatures ranging from 800°C to 1200°C for times that ensured sufficient broadening of the spikes. Another set of samples was annealed at the same times and temperatures in N2. Dopant depth profiles were measured before and after diffusion by secondary ion mass spectrometry (SIMS). At the test samples we observed thermal diffusion of B and Sb, oxidation enhanced diffusion of B and oxidation retarded diffusion of Sb, all in accordance with the literature. In contrast to this, oxidized silicide capped samples showed a retardation of B diffusion by a factor of 2 - 10 as compared to thermal diffusivity and an enhancement of Sb diffusion by a factor of 1 - 2.
Phosphorus Diffusion From Doped Si1−xGex, Films into Silicon
Authors: Kobayashi S. , Iizuka M. , Aoki T. , Mikoshiba N. , Sakuraba M. , Matsuura T. , Murota J. 
Published: April 2011

ABSTRACTPhosphorus diffusion from in-situ doped Si1−xGex epitaxial films into Si at 800°C was investigated using secondary ion mass spectroscopy and differential resistance measurements. The surface P concentration in the diffused layer in Si was higher than the P concentration in the Si1−xGex, film in the present conditions, which signifies the segregation of P from the Si1−xGex, film into Si. The segregation coefficient, defined as the ratio of the active P concentration in the Si to that in the Si1−xGex, film, was about 2.5 in the case of the Si0.75Ge0.25 film as a diffusion source and increased with increasing Ge fraction. The P diffusion profiles in Si were normalized by x/√, even though the segregation of P occurred. The high concentration diffusion characteristics of P in Si were similar to those reported by using conventional diffusion sources.
Fabrication of Shallow Junctions with Conventional Furnace Equipment by Using Silicon Preimplants
Authors: Puchner H. , Aronowitz S. 
Published: April 2011

ABSTRACTThe global scaling down of device dimensions requires process technologies which are able to create ultra-shallow junctions. Besides using ultra-low implant energies for shallow junction creation we present an alternative approach for the creation of MDD (Medium Doped Drain) junctions by using moderately low implant energies. Our approach employs the dopant/point-defect interaction mechanism to retard dopant diffusion as well as dopant de-activation in the tail of the diffusion profiles to achieve suitable shallow junctions. The silicon preimplant allows fabrication of 90nm arsenic, 150nm phosphorus, and 140nm boron metallurgical junctions for a 40keV arsenic, 20keV phosphorus, and 8keV boron implant.
Real Time Characterization of Non-Ideal Surfaces and Thin Film Growth by Advanced Ellipsometric Spectroscopies
Authors: Collins R. W. , Rovira P. I. , Ferlauto A. S. , Koh Joohyun , An Ilsin , Zapien J. A. , Messier R. , Wronski C. R. 
Published: April 2011

ABSTRACTThe development of multichannel ellipsometers with photodiode array-based detection systems has enabled real time spectroscopic ellipsometry (SE), a technique now being used widely to study surface modification and thin film growth. Multichannel ellipsometers based on the rotating-element design acquire spectroscopic data in parallel and thus offer advantages over other designs. The simplest rotating-element multichannel ellipsometers are constructed using a rotating polarizer or analyzer for polarization state modulation or detection. These configurations have a number of drawbacks, in particular, their insensitivity when measuring samples that reflect linearly polarized light and their susceptibility to errors when measuring samples having unrecognized non-idealities (e.g., macroscopic inhomogeneities) that generate a mixture of polarization states in the reflected beam. In this review, we describe recent advances in multichannel ellipsometry including (i) enhancement of the spectral range of the rotating-polarizer multichannel ellipsometer to 1.5–6.5 eV, (ii) adaptation of the rotating-compensator configuration to multichannel ellipsometry for studies of weakly absorbing and macroscopically inhomogeneous materials, and (iii) development of a dual rotating-compensator multichannel ellipsometer design for real time studies of optically anisotropic materials. As a recent example of the application of rotating-compensator multichannel ellipsometry, we describe analyses of (i) a macroscopically-rough (textured) tin-oxide (Sno2) film on a glass substrate and (ii) the fabrication of the p-layer component of an amorphous silicon-based p-i-n solar cell on the textured SnO2 film surface at a temperature of 200°C.
In Situ Spectroscopic Ellipsometry Studies of The Interaction Process of Ethene With Si Surfaces During Sic Formation
Authors: Wöhner T. , Stauden Th. , Cimalla V. , Eichhorn G. , Schaefer J.A. , Pezoldt J. 
Published: April 2011

ABSTRACTThe interaction of ethene with silicon (111) surfaces at different process temperatures (580°C, 680°C, 780°C) was monitored in situ by spectroscopic ellipsometry. It is shown that spectroscopic ellipsometry is a reliable method to monitor the carbonization process of silicon surfaces. Different SiC formation stages (incubation time, (√3×√3)R30° reconstruction, 2D growth and 3D growth) were observed using complimentary analyzing techniques. The change of the ellipsometric signal as a function of process time is related to these stages and was interpreted using an optical model which consists of four layers (surface roughness, SiC layer, interface layer, Si substrate).