bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bulk Mechanical Properties Of Quasicrystals
Authors: Takeuchi S. 
Published: April 2011

AbstractElastic moduli, anharmonicity, hardness and high temperature plastic behavior of icosahedral and decagonal quasicrystals are reviewed. Elastic properties are discussed in relation to the bonding nature of the quasicrystals. The plastic deformation behavior at high temperatures is discussed based on the characteristics of the dislocation mechanism in the quasiperiodic lattice. A Peierls potential, a phason relaxation and a dragging stress due to production of a defect field are considered as the controlling factors for the thermally activated dislocation glide; a dislocation in quasiperiodic lattice is accompanied not only by the elastic (phonon) strain field but also by the phason strain field which is difficult to be relaxed completely with the dislocation glide.
The Activation Parameters And The Mechanisms Of Plastic Deformation Of Al-Pd-Mn Single Quasicrystals
Authors: MessersChmidt U. , Geyer B. , Bartsch M. , Feuerbacher M. , Urban K. 
Published: April 2011

AbstractIn situ straining experiments on Al-Pd-Mn single quasicrystals in a high-voltage electron microscope between 675 °C and 750°C showed viscously moving dislocations with segments oriented in preferred directions. First measurements from video recordings indicate that dislocations on parallel traces move at two different velocities. For the first time, macroscopic samples were deformed in compression below 680 °C. Above a transition temperature of about 635°C for specimens of a fivefold compression axis and a strain rate of 10−5 s−1, the specimens show a yield point followed by a range of steady state deformation. Below that temperature, they are brittle. However, plastic deformation was achieved down to 555°C by using a lower strain rate and performing stress relaxation tests before the fracture stress was reached. The samples then show very strong work-hardening. The rapid decrease of the activation volume with decreasing temperature, which is characteristic of the high-temperature range, does not continue at low temperatures.The results are interpreted by dislocation generation and recovery and by the cluster friction mechanism controlling the dislocation mobility.
Colorless High Dielectric Compounds for Low Voltage Liquid Crystal Application
Authors: Wu Shin-Tson , Schwartz Robert N. , Zhang Qing T. , Marder Seth , Hsu Chain-Shu 
Published: April 2011

ABSTRACTSeveral colorless compounds with dielectric anisotropy in the 10-50 range were studied. The absorption spectra, phase transition temperature, birefringence, dielectric anisotropy and visco-elastic coefficient of these compounds were measured.
Advances in Holographic Polymer Dispersed Liquid Crystal Technology
Authors: Bowley C. C. , Fontecchio A. K. , Lin J.-J. , Yuan H. , Crawford G. P. 
Published: April 2011

ABSTRACTWe discuss recent advances in reflective holographically-formed polymer dispersed liquid crystal materials in the context of their suitability for reflective display applications. A dual-domain phenomenon resulting in a broadened reflection peak is presented. A simple phenomenological model is developed to explain this unusual effect The effect of monomer functionality on the reflectance characteristics of these materials is also discussed. Monomers of effective functionality ∼4.5 yield the brightest holograms, however, the data suggests that these systems are currently far from optimal.
Characterization of Plated Cu Thin Film Microstructures
Authors: Gignac L. M. , Rodbell K. P. , Cabral C. , Andricacos P. C. , Rice P. M. , Beyers R. B. , Locke P. S. , Klepeis S. J. 
Published: April 2011

ABSTRACTElectroplated Cu was found to have a fine as-plated microstructure, 0.05 ±0.03 μm, with multiple grains through the film thickness and evidence of twins and dislocations within grains. Over time at room temperature, the grains grew to greater than 1 μm in size. Studied as a function of annealing temperature, the recrystallized grains were shown to be 1.6 ± 1.0 μm in size, columnar and highly twinned. The grain growth was directly related to the time dependent decrease in sheet resistance. The initial grain structure was characterized using scanning transmission electron microscopy (STEM) from a cross-section sample prepared by a novel focused ion beam (FIB) and lift-out technique. The recrystallized grain structures were imaged using FIB secondary electron imaging. From these micrographs, the grain boundary structures were traced, and an image analysis program was used to measure the grain areas. A Gaussian fit of the log-normal distribution of grain areas was used to calculate the mean area and standard deviation. These values were converted to grain size diameters by assuming a circular grain geometry.
Bath Additive and Current Density Effects on Copper Electroplating Fill of Cu Damascene Structures
Authors: Mikkola Robert D. , Jiang Qing-Tang , Carpio Ronald , Carpenter Brad 
Published: April 2011

ABSTRACTCopper electroplating has become the leading technology for gap fill of damascene structures on advanced interconnects. A key to developing a robust electroplating process that produces deposits free of voids and seams is understanding the role of the additive components, i.e., levelers, brighteners and wetting agents, and their relative diffusion/adsorption characteristics. Additionally, obtaining insight about the cathodic current/potential relationship is critical for maximizing the effectiveness of the additive components.Our results indicate that bath additive composition and the plating parameters (plating pulse frequency, and current density) play critical roles in the outcome of the Cu fill. SEM cross sectional analysis of timed partial electroplating fill studies show two types of fill, 1) conformal and 2) bottom-up. Conformal fill of features smaller than 0.25 μm with an aspect ratio (AR) of 4.0 tends to form seam voids in the center of the structure. These seam voids can lead to early electromigration failures. On the other hand, bottom-up fill leads to a void free Cu deposit within the feature.
CMP Fundamentals and Challenges
Authors: Oliver Michael R. 
Published: April 2011

Chemical Mechanical Polishing (CMP) as a semiconductor polishing technology has grown dramatically during the past decade. It has been a key enabling technology, facilitating the development of high density multilevel interconnects. Its widespread application has exceeded the growth of the scientific understanding.Models for silicon dioxide polishing mechanisms have built upon the work originally done for glass polishing. Recent work has augmented our insight, but our understanding is far from complete. A quantitative picture of the basic interaction mechanisms for silicon dioxide polishing does not yet exist. The models for metal polishing are now an active area of investigation. Recent work has demonstrated that more work is need to adequate explain the CMP of metals. The metal CMP mechanisms appear to be substantially more complex than originally assumed.The challenges for CMP have been to improve the performance of the technology, and increasingly this needs a foundation of scientific understanding to achieve the needed gains. We can expect that, as the scientific foundation grows, it will contribute significantly to manufacturing improvements as has been the case in other areas of semiconductor technology.
Development of High Purity One Atm Ozone Source - Its Application to Ultrathin SiO2 Film Formation on Si Substrate
Authors: Koike Kunihiko , Inoue Goichi , Ichimura Shingo , Nakamura Ken , Kurokawa Akira , Nonaka Hidehiko 
Published: April 2011

ABSTRACTA high-concentration ozone generator operating at atmospheric pressure has been developed for fabrication of ultra thin silicon oxide films. The generator can supply atmospheric pressure of ozone jet with ozone concentration up to 80 vol%. The ozone jet is generated by desorbing ozone at nearbyn room temperature, which has been condensed on silica-gel by passing ozone/oxygen mixture gas from a commercial ozonizer at a low temperature (<-50°C); at the temperature ozone is more selectively adsorbed on silica-gel than oxygen. The high purity ozone jet with a concentration of 25 vol% at a pressure of 1 × 105 Pa had so large oxidation power that SiO2 film as thick as 3.3 nm grew on a Si surface after 60 min exposure at 375°C. The density of the film was equivalent to that of the film formed by a conventional thermal oxidation process, judging from etching rate with dilute HF solution.
Modeling Soft Breakdown of Ultra-Thin Gate Oxide Layers
Authors: Houssa Michel , Mertens P.W. , Heyns M.M. 
Published: April 2011

ABSTRACTThe time-dependent dielectric breakdown of MOS capacitors with ultra-thin gate oxide layers is investigated. After the occurrence of soft breakdown, the gate current increases by 3 to 4 orders of magnitudes and behaves like a power law of the applied gate voltage. It is shown that this behavior can be explained by assuming that a percolation path is formed between the electron traps generated in the gate oxide layer during electrical stress of the capacitors. The time dependence of the gate voltage signal after soft breakdown is next analysed. It is shown that the fluctuations in the gate voltage are non-gaussian as well as that long-range correlations exist in the system after soft breakdown. These results can be explained by a dynamic percolation model, taking into account the trapping-detrapping of charges within the percolation cluster formed at soft breakdown.
Effect of Thermal Stability and Roughness on Electrical Properties of Tantalum Oxide Gates
Authors: Alers G.B. , Stirling L.A. , Vandover R.B. , Chang J.P. , Werder D.J. , Urdahl R. , Rajopalan R. 
Published: April 2011

ABSTRACTGate dielectrics with an effective SiO2 thickness of 1.6 nm (100 Hz) have been fabricated using chemical vapor deposition of tantalum oxide directly on silicon. A low temperature plasma anneal process was used to passivate excess traps in the oxide layer and to avoid degradation of capacitance and leakage after high temperature processing. Stable capacitance-voltage characteristics were obtained after the plasma anneal with an interface state density of ∼ 1012 cm−2 before post metallization anneal. We have examined the impact of high temperature processes and crystallization on the roughness for 10nm – 50nm films of Ta2O5 films on Si and SiN. The impact of roughness on capacitance and leakage current is examined through calculations assuming a Gaussian distribution of thickness across the capacitor with two conductive contacts. It is found that when the rms roughness exceeds about 20% of the film thickness then an increase in capacitance is observed that can be mistaken as an effective dielectric constant increase. The increase in capacitance due to roughness is accompanied by an exponential increase in leakage currents that ultimately degrades the charge storage capacity of the oxide.
Photo-Induced CVD of Tantalum Pentoxide Dielectric Films Using an Injection Liquid Source
Authors: Zhang J.-Y. , Boyd I.W. , Mooney M.B. , Hurley P.K. , O'sullivan B.J. , Beechinor J.T. , Kelly P.V. , Crean G.M. , Senateur J.-P. 
Published: April 2011

ABSTRACTIn this paper the new technique of ultraviolet-assisted injection liquid source (UVILS) chemical vapour deposition (CVD) of thin tantalum pentoxide films on p-type Si (100) wafers is presented. This method involves the use of a krypton chloride (KrCl*) excimer lamp, radiating at 222 nm, and a novel injection liquid source capable of delivering precisely controllable quantities of a novel high-volatility liquid metalorganic precursor into the CVD chamber. The physical and chemical properties of the films formed have been studied using spectroscopic ellipsometry and Fourier transform infrared spectroscopy measurements while the electrical properties of the films were determined by surface charge analysis, capacitancevoltage, and current-voltage measurements. Simple metal/oxide/silicon capacitor structures incorporating this tantalum pentoxide have been fabricated. Refractive index values of 2.09±0.07, dielectric constant values of 18-24, fixed oxide charge content of < 1 × 1011 cm−2 and breakdown fields higher than 2 MV/cm can be readily obtained in the as-deposited films.
Effect of Al, Ta, and O Precursors on Growth and Properties of Al2O3 and Ta2O5 Thin Films Deposited by Triode PECVD
Authors: Klein Tonya , Niu Dong , Parsons Gregory 
Published: April 2011

ABSTRACTIn this article, the properties of plasma deposited Al2O3 and Ta2O5 thin films (k ≈ 12 and 25 respectively) are discussed as possible high k alternatives to SiO2. The films were formed in a 4” compatible triode plasma CVD reactor using Ta(V)ethoxide for Ta2O5 and Al acetylacetonate, Al tri-sec-butoxide, Al triisopropoxide, and triethyldialuminum tri-sec-butoxide metal organic precursors for Al2O3. Precursors were heated to 150 °C and delivered to the reactor with He and Ar carrier gases downstream from the plasma. For Ta2O5 films, film properties were strongly dependent on the oxygen precursor, with O2 resulting in higher growth rates, better uniformity, and better stability to water exposure than films deposited using N2O. For Al2O3, distinct differences in OH and C incorporation were observed for the various Al and O precursors studied. In particular, films deposited from alkoxides had higher concentrations of OH and C, and had higher leakage currents. For films deposited with triethydialuminum tri-sec-butoxide, the N2O plasma O atom source resulted in smaller leakage currents and less C than an O2 plasma. Temperature dependence of the deposition rates and the leakage currents was also observed.
Incorporation and Role of Nitrogen During Oxynitridation of Silicon Studied by Photoelectron Spectroscopy
Authors: Suzuki Masayuki , Saito Yoji 
Published: April 2011

ABSTRACTWe tried direct oxynitridation of silicon surfaces by remote-plasma-exited nitrogen and oxygen gaseous mixtures at 700°C in a high vacuum. The oxynitrided surfaces were investigated with in-situ X-ray photoelectron spectroscopy. With increase of the oxynitridation time, the surface density of nitrogen gradually increases, but that of oxygen shows nearly saturation behavior after the rapid increase in the initial stage. We also annealed the grown oxynitride and oxide films to investigate the role of the contained nitrogen. The desorption rate of oxygen from the oxynitride films is much less than that from oxide films. We confirmed that nitrogen stabilizes the thermal stability of these oxynitride films.
First-Principles Study of Vacancy-Assisted as Diffusion in Silicon
Authors: Xie Jianjun , Chen S.P. 
Published: April 2011

ABSTRACTA set of interaction potentials for vacancy-assisted As diffusion in silicon have been provided via first-principles pseudo-potential calculations. Some important reactions such as As+V ⇌ AsV, AsV + As ⇌ As2V, AsV + V ⇌ V2, as well as V + V ⇌ V2 are considered. The results demonstrate that the existence of another As atom greatly reduces the migration barrier of vacancy moving between the two As atoms and speeds up the diffusion of As. The AsV pair can attract another nearby vacancy. The binding force mainly comes from the binding between two vacancies, rather than from the AsV pair. The obtained potential energy diagrams provide input information for atomistic diffusion simulations.
Effect of Extended Defects on the Enhanced Diffusion of Phosphorus Implanted Silicon
Authors: Keys P. H. , Li J. H. , Heitman E. , Packan P. A. , Law M. E. , Jones K. S. 
Published: April 2011

ABSTRACTExtended defects resulting from ion implantation are believed to act in some cases as a driving force behind transient enhanced diffusion (TED). We use secondary ion mass spectrometry (SIMS) to study the diffusion enhancements of an underlying boron doped spike after creating implant damage in the near surface region. Diffusion enhancements are compared for silicon implants and phosphorus implants to distinguish between factors related to chemical species interactions versus those related to ion beam damage. Transmission electron microscopy (TEM) is used to investigate the existence and dissolution of extended defects. {311} extended defects are clearly visible in self-implanted samples but absent in phosphorus doped samples. The extended defects resulting from phosphorus implantation are small (20Å to 60Å diameter) “dot” defects barely resolvable by conventional TEM. methods. Despite the marked differences in defect morphology, diffusion enhancements in the boron marker layer are observable for both species. Results comparing the TED of a buried marker layer after P+ and Si+ show a larger overall effective diffusion length results after high dose (1x1014 cm−2) phosphorus implants. Visible defects in phosphorus implanted silicon are not the only source of TED, suggesting the existence of sub-microscopic phosphorus interstitial clusters (PIC). This provides important insight into the affect of phosphorus on TED.
In-Situ Observation of UV/Ozone Oxidation of Silicon using Spectroscopic Eli Psometry
Authors: Saitoh T. , Kobayashi D. , Kimura D. , Asai K. 
Published: April 2011

ABSTRACTInitial oxidation process of silicon in UV/ozone ambient has been monitored using a multi-wavelength, in-situ spectroscopic ellipsometry. Ozone gas was chemically formed by photochemical reaction of oxygen under ulUmviolet illuimination. The oxide growth was monitored for hydrogenated silicon surfaces as functions of oxygen gas flow rate, gas pressure and wafer temperature. Initial oxidation rates were very high at almost all the temperatures. The oxidation rate was 0.2 nm/min about ten times higher than that for thermal oxidation without UV light at low temperatures. The accelerated oxidation was probably due to an electric field effect on the oxidation of back-bond silicon by active oxygen atoms included in the ozone gas.
In Situ Diagnostics of Methane/Hydrogen Plasma Interactions with Si(100)
Authors: Duan H. L. , Bent Stacey F. 
Published: April 2011

ABSTRACTMethane/hydrogen plasmas have been reported to be sources both for a-C:H film deposition and for compound semiconductor etching. In this work, an in situ diagnostic study of methane/hydrogen plasma interactions with a silicon surface is carried out, focusing on the effect of hydrogen dilution. A remote electron cyclotron resonance (ECR) plasma using a H2/Ar mixture excites methane gas near a Si(l 00) substrate. In situ multiple internal reflection Fourier transform infrared (MIR-FTIR) spectroscopy is used to probe the surface species at different hydrogen dilution ratios. We find that at low methane pressure without hydrogen dilution, a-C:H films are deposited. With H2 dilution, the results suggests that some sputter/etching of the silicon surface occurs. Hence, methyl groups are identified as potential etchants for silicon materials. The data suggest that there is a competition between etching and deposition chemistry which depends strongly upon the methane pressure and hydrogen ratio in the plasma.
In-Situ Real-Time Ellipsometry Study of Dynamic Processes of YBa2Cu3O7−x Thin Films
Authors: Gao Y. , Mueller A.H. , Irene E.A. , Auciello O. , Krauss A.R. , Schultz J.A. 
Published: April 2011

ABSTRACTThe optical absorption peak at 4. leV associated with oxygen deficiency in YBa2Cu3O7−x thin films was monitored by spectroscopic ellipsometry (SE) in real time during the growth process. Two regimes dominated by oxygen out- and in-diffusion have been observed during deposition by ion beam sputtering at 700°C.The effect of oxygen partial pressure during the post-deposition cooling process on the oxidation of deposited films has also been investigated. The thermodynamic stability of the grown films was examined by real time SE during post annealing process. In-situ SE measurements have been performed to obtain the dielectric function of oxygen deficient YBa2Cu3O6 films in the temperature range from 27°C to 700°C. It has been demonstrated that real time SE is a sensitive and useful technique for in-situ diagnostics of the dynamics of YBa2Cu3O7−x thin film processes.
Differential Anomalous X-Ray Scattering Techniques for Determination of Liquid and Amorphous Structures
Authors: Warburton W. K. , Ludwig K. F. , Wilson L. , Bienenstock A. 
Published: April 2011

AbstractThe differential anomalous scattering technique is outlined and compared to other techniques for studying short-range order in amorphous systems, such as EXAFS. The differential distribution functions obtained for liquid GeBr4 were found to support a model for the liquid state based on the structure of the h.c.p. crystal. Application of the technique to aqueous ZnBr2 also allowed discr imination between structural models.
An Atomic View of Surface Diffusion on Metals
Authors: Ehrlich Gert 
Published: April 2011

AbstractAtomic migration in crystals is obscured by the crystal itself, and it has therefore taken ingenious indirect methods to study the diffusion process. In contrast, diffusion at surfaces is amenable to fairly direct examination, on the atomic level, through the use of the field-ion microscope. By combining measurements of the mean-square displacement with determinations of the distance distribution function, considerable detail about atomic jumps in diffusion can be obtained. Here we will briefly review results obtained by field-ion microscopic examination of single metal atoms and metal clusters diffusing on metal crystals.What is noteworthy in the diffusion of single metal atoms is the variety of behavior which is dictated by the nature of the substrate, and the occasional complexity of the diffusion process. Examples of substrate-specific effects in atomic migration will be given for both fcc and bcc metals. Another surprising aspect of diffusion on metal surfaces is the role of clusters. These are stable at relatively high temperatures, and often diffuse at rates comparable to those of single atoms. The status of such cluster studies will be briefly examined, not only for their significance in surface transport, but also for their interest in understanding cohesion at metal surfaces.
1.55 Micron Emission from InAs/InP Self-Assembled Quantum Dots
Authors: Murray Ray , Bryan Caroline , Button Chris , Spikes D. , Hill G. 
Published: April 2011

ABSTRACTSelf-assembled InAs/InP and InAs/InGaAsP quantum dots (QDs) grown by metal-organic chemical vapour epitaxy (MOVPE) exhibit emission at 1.5–1.6 μm at room temperature. P-I-N diodes incorporating a single InAs/InGaAsP QD layer exhibit strong electroluminescence over a wide range of input currents and emit significantly more light per layer than a InGaAs/InGaAsP multi-quantum well device.
Mid-Infrared Emission in InAs/GaAs Self-Assembled Quantum Dots
Authors: Boucaud P. , Sauvage S. , Brunhes T. , Glotin F. , Prazeres R. , Ortega J. M. , Thierry-Mieg V. , Lemaître A. , Gérard J. M. 
Published: April 2011

ABSTRACTWe have investigated the emission properties of InAs/GaAs self-assembled quantum dots in the mid-infrared. The emission relies on the intraband transitions in the valence band of the quantum dots. We first show that third-harmonic generation can be observed. The frequency tripling efficiency is enhanced by the resonances between the pump excitation and the quantum dot intraband transitions. A giant third-order nonlinear susceptibility is measured for one dot plane. The narrow spectral dependence of the nonlinear susceptibility is well explained by simulations which account for the three-dimensional confinement potential. We secondly show that the mid-infrared spontaneous emission between hole confined states can be observed under an interband optical pumping. The spontaneous emission involves transitions between either the ground and excited states or between excited states. These measurements demonstrate the potentiality of self-assembled quantum dots for mid-infrared emission.