bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization of Ti and Co Self-Aligned Silicide RTP for 0.10 μm Cmos
Authors: Kittl J. A. , Hong Q. Z. , Yang H. , Yu N. , Rodder M. , Apte P. P. , Shiau W. T. , Chao C. P. , Breedijk T. , Pas M. F. 
Published: April 2011

ABSTRACTAs CMOS technologies are scaled to 0.10 μm and beyond, self-aligned silicide (salicide) processes find difficult challenges. As junction depths and linewidths are scaled, achieving both low sheet resistance and low contact resistance maintaining low diode leakage becomes increasingly difficult. In this paper we present studies of Ti and Co salicide processes implemented into a 0.10 μm CMOS technology. We show that both for Ti and Co, the optimization of RTP parameters plays a crucial roll in achieving a successful implementation. For Co salicide, optimization of RTP conditions results in elimination of shallow junction leakage (its main scaling problem). Two-step RTP and one-step RTP Ti salicide processes are compared, showing the advantages of one-step RTP. The RTP process windows for low resistance narrow gates (the main scaling issue for Ti salicide) are analyzed. Processes with pre-amorphization, with Mo doping and with a combination of both are compared. An optimal process using Mo and preamorphization implants and one-step RTP is shown to result in excellent device characteristics and low resistance to 0.06 μm gates.
Interfacial Stability and Surface Morphology in Layer-By-Layer Semiconductor Heteroepitaxy Luis
Authors: Zepeda-Ruiz A. , Maroudas Dimitrios , Weinberg W. Henry 
Published: April 2011

AbstractA theoretical analysis based on continuum elasticity theory and atomistic simulations is presented of the interfacial stability with respect to misfit dislocation formation and of the film surface morphology during layer-by-layer growth semiconductor heteroepitaxy. The strain in the coherently strained films, the energetics of a transition from a coherent to a semicoherent interface consisting of misfit dislocation arrays or networks, and the morphological details of the film surface profile are calculated for InAs/GaAs(110) and InAs/GaAs(111)A. The analysis is presented for the general case of heteroepitaxy on a finite-thickness compliant substrate. The results are discussed in the context of recent experimental data.
Epitaxial Growth and Magnetism
Authors: Dreysse H. , Freyss M. , Stoeffler D. 
Published: April 2011

AbstractGrowth phenomena and magnetism of metallic films are not easy to describe at the same level of precision. A small variation of distances can drastically modify the magnetic properties of thin metallic films. In this contribution different aspects encountered in the growth of thin magnetic metallic films are addressed. Within an itinerant magnetism scheme, the main difficulty arises from the number of possible magnetic arrangements induced by the competition between nearest-neighbors Ferromagnetic and Antiferromagnetic couplings. However we show that the description of the electronic and magnetic structure at T = 0 K by well-established band structure frameworks provides useful and precise information on the growth of a transition metal on another. Due to the large amount of experimental data available, the Fe/Cr system is taken as an example. The influence of steps at the interface is discussed and the possibility of magnetic domains is shown. A simple model of growth taking into account variable interdiffusion rate and layer-by-layer quality is given. These simulations are used to explain experimental results where interdiffusion at the interface is very common.
Simulation of the Growth of Heterostructures
Authors: Harding J.H. , Harker A.H. 
Published: April 2011

AbstractThe production and morphology of hetero-structures presents problems at a variety of length-scales. A common problem is the production and accommodation of stresses in the film due to mis-match. We shall first discuss examples of atomistic nucleation and growth at interfaces and the use of atomistic simulations to obtain parameters for rate-theory models of cluster and film growth. We shall then consider the effect of stress on growing films. In strained-layer semi-conductor systems, for example, the growth of small islands gives rise to stress distributions which differ strongly from those in continuous layers. Interesting strain effects are also observed in ceramics. We will discuss the relationship between stress and the growth and morphology of films, where effective medium models may be used to derive effective bulk properties for films with imperfections such as porosity and cracks.
Optical Fiber Interconnect Subjected to a Not-Very-Small Ends Off-Set: Effect of the Reactive Tension
Authors: Suhir E. 
Published: April 2011

AbstractWe examine the mechanical response of an optical fiber interconnect clamped (by epoxy bonding or soldering) at the ends and then subjected to a not-very-small lateral ends off-set. The term “not-very-small” is used here to indicate that the off-set is small enough to apply the elementary (linear) beam theory, but, at the same time, is large enough, so that the effect of the reactive tension has to be accounted for. The obtained results can assist a reliability engineer to make, if necessary, the appropriate changes in the photonic package design.
Optical Fiber Strength and Its Relationship to Dynamic Mechanical Properties of Fiber Coatings by Direct Measurements on Fibers
Authors: Gebizlioglu O. S. , Kurkjian C. R. 
Published: April 2011

AbstractWhile the telecommunications optical fiber technology is in its third decade of growth, and fibers that are aging-resistant and fatigue-resistant are highly desirable, basic physico-chemical aspects of fiber aging and mechanical strength degradation are not well understood. A key difficulty to understanding fiber strength degradation has been the unavailability of tools for direct assessments of the condition of fiber coatings on aged fibers. In this presentation, we report on our studies of the effects of DI-water aging on two experimental high n-value (fatigue-resistant) fibers and their coatings. We have found that the coatings of these high n value fibers are highly resistant to DI-water aging.
Time- and Temperature-Dependent Material Behavior and its Impact on Low-Temperature Performance of Fiber Optic Cables
Authors: Gebizlioglu Osman S. 
Published: April 2011

AbstractA series of service-affecting field failures in cold weather (−40°C to 0°C) initially and in more moderate conditions (up to 15° C) recently have raised concerns about the temperaturedependent transmission performance of loose tube fiber optic cables. The first field failures occurred in 1550-nm aerial transmission lines while more recent failures have affected 1310-nm operations. Field analyses and laboratory temperature-cycling measurements of the affected cables established that the transmission loss resulted from fiber microbending due to random fiber contacts with the buffer tube walls caused by the axial shrinkage of the buffer tubes relative to the cable central member. High resolution thermal expansion/contraction measurements on commonly used PBT (Polybutylene Terephthalate) and PP (Polypropylene) buffer tubes indicated that the total axial shrinkage consists of two components: irreversible shrinkage due to the relaxation of processing-induced stresses and reversible thermal contraction/expansion. The magnitude of both components depends strongly on the buffer tube material and the processing conditions used to manufacture buffer tubes. In this report, we review our work to date in developing field installation and cable design solutions, present a comparison of two buffer tube materials, identify key materials issues that determine buffer tube dimensional stability, and discuss the implications of these issues on the field installation and cable design solutions that we have developed to minimize the risk of low-temperature transmission loss in loose tube cables.
Reliability Assessment of Optical Fibers and Fiber Gratings
Authors: Kannan Sriraman , Lemaire Paul 
Published: April 2011

AbstractThe topic of reliability of UV-induced fiber gratings is reviewed. Approaches to assess and predict changes in optical properties of fiber gratings due to thermal decay of refractive index modulation are presented and compared. The mastercurve/demarcation energy diagram approach is shown to be a powerful and general method for the purpose. The process of thermal stabilization to obtain gratings with superior stability is delineated. It is shown that the mastercurve approach could be used to analyze other reliability problems such as in predicting hydrogen-induced losses in fibers.
InGaN/GaN/AlGaN-Based Leds and Laser Diodes
Authors: Nakamura S. , Senoh M. , Nagahama S. , Iwasa N. , Matushita T. , Mukai T. 
Published: April 2011

AbstractInGaN quantum-well-structure blue LEDs were grown on epitaxially laterally overgrown GaN (ELOG) and sapphire substrates. The output power of both LEDs was as high as 6 mW at a current of 20 mA. The LED on sapphire had a considerable amount of leakage current in comparison with that on ELOG. These results indicate that In composition fluctuation is not caused by threading dislocations (TDs), free carriers are captured by radiative recombination centers before they are captured by nonradiative recombination centers in InGaN, and that the dislocations form the leakage current pathway in InGaN. Red LED with an emission peak wavelength of 650 nm was fabricated by increasing the In composition and thickness of InGaN well layer. When the laser diodes (LD) was formed on the GaN layer above the SiO2 mask region, the threshold current density was as low as 3 kAcm-2. When the LD was formed on the window region, the threshold current density was as high as 6 to 9 kAcm-2. There is a possibility that a leakage current due to a large number of TDs caused the high threshold current density on the window region. InGaN multi-quantum-well (MQW) structure LDs grown on the ELOG substrate showed an output power as high as 420 mW under RT-CW operation. The longest lifetime of 9,800 hours at a constant output power of 2 mW was achieved. The InGaN MQW LDs were fabricated on a GaN substrate. The fundamental transverse mode was observed up to an output power of 80 mW.
GaN Homoepitaxy for Device Applications
Authors: Kamp M. , Kirchner C. , Schwegler V. , Pelzmann A. , Ebeling K.J. , Leszczynski M. , Grzegory I. , Suski T. , Porowski S. 
Published: April 2011

AbstractEpitaxial growth on GaN single bulk crystals sets new standards in GaN material quality. The outstanding properties provide new insights into fundamental material parameters (e.g. lattice constants, exciton binding energies, etc.) being not accessible by heteroepitaxial growth on sapphire or SiC. With MOVPE and MBE we realized unstrained GaN layers with dislocation densities about six orders of magnitude lower than in heteroepitaxy. Those layers revealed an exceptional optical quality as determined by a reduction of the photoluminescence linewidth from 5 to 0.1 meV and a reduced XRD rocking curve width from 400 to 20 arcsec.Only recently, progress in surface preparation allowed morphologies of the layers suitable for device applications. We report on InGaN/GaN MQW structures as well as the first GaN pn- and InGaN/GaN double heterostructure LEDs on GaN single bulk crystals. Those LEDs are twice as bright as their counterparts grown on sapphire. In addition they reveal an improved high power characteristics, which is attributed to an enhanced crystal quality and an increased p-doping. Time resolved electroluminescence measurements proof that band/band recombination is the dominant emission mechanism for the InGaN/GaN LEDs.
Electron Beam Induced Impurity Electro-Migration in Unintentionally Doped GaN
Authors: Toth M. , Fleischer K. , Phillips M. R. 
Published: April 2011

AbstractElectron beam induced electromigration of ON+ and H+ impurities in unintentionally n-doped GaN was investigated using cathodoluminescence (CL) kinetics profiling, CL imaging of regions pre-irradiated with a stationary electron beam, and wavelength dispersive x-ray spectrometry (WDS). The presented results (i) illustrate induced impurity diffusion in wide bandgap semiconductors, (ii) provide experimental evidence for the (VGa-ON)2- model of yellow luminescence in GaN with low Si content (ii) confirm the roles of 0 in frequently reported bound exciton and donor-acceptor pair emissions and (iv) suggest the involvement of ON+ and hydrogenated gallium vacancies in a blue emission in autodoped GaN.
Molecular Beam Epitaxy of High Quality InGaN Alloys Using Ammonia: Optical and Structural Properties
Authors: Grandjean Nicolas , Massies Jean , Leroux Mathieu , Laügt Marguerite , Vennéguès Philippe , Dalmasso Stéphane , Ruterana Pierre , Hirsch Lionel , Barrière Serge 
Published: April 2011

AbstractThe growth of InGaN layers was carried out by molecular beam epitaxy (MBE). The nitrogen precursor was ammonia. The optical and structural properties of the InGaN layers have been investigated by transmission electron microscopy (TEM), x-ray diffraction (XRD) and photoluminescence (PL). For optimized growth conditions, the PL spectrum of InGaN (x=0.1) alloy is narrow (FWHM ≤ 50 meV) and the Stokes shift measured by PL excitation is weak (<50 meV), i.e. near band edge transitions are observed. Under these conditions, flat surfaces can be obtained, and InGaN/GaN quantum wells (QWs) with sharp interfaces can be grown. On the other hand, when growth conditions depart from a narrow optimum window, the structural quality of the samples strongly degrade, whereas the luminescence spectra are dominated by deep levels, exhibiting a strong Stokes shift. MBE grown light emitting diodes (LEDs) using InGaN/GaN QWs have been fabricated. Their electroluminescence (EL) peaks at 440 nm at 300K.
Computational Materials Science, an Increasingly Reliable Engineering Tool: Anomalous Nitride Band Structures and Device Consequences
Authors: Sher A. , Schilfgaarde M. van , Berding M. A. , Krishnamurthy S. , Chen A.-B. 
Published: April 2011

AbstractComputational materials science has evolved in recent years into a reliable theory capable of predicting not only idealized materials and device performance properties, but also those that apply to practical engineering developments. The codes run on workstations and even now are fast enough to be useful design tools. A review will be presented of the current status of this rapidly advancing field. Examples of the accuracy of the codes are displayed by comparing the predicted atomic volumes, and cohesive and excess energies of several materials with experiment. As a further demonstration of the methods, the band structures of AIN, GaN, and InN in wurtzite and zinc blende structures will be presented. There are anomalies in the conduction and valence bands of these materials. Some consequences on light emitting and power devices made from these materials will be examined.
Spectroscopy of Proton Implanted GaN
Authors: Weinstein M.G. , Stavola M. , Song C.Y. , Bozdog C. , Przbylinska H. , Watkins G.D. , Pearton S.J. , Wilson R.G 
Published: April 2011

AbstractVibrational spectroscopy, photoluminescence, and optically detected electron paramagnetic resonance (ODEPR) have been used to characterize the defects produced in undoped and Si-doped GaN by the implantation of hydrogen. Several new vibrational bands were found near 3100 cm-1 in GaN that had been implanted with protons. These frequencies are close to those predicted for VGa-Hn complexes, leading to the tentative assignment of the new lines to VGa defects decorated with different numbers of H atoms. The proton implantation also produces an infrared PL band centered at 0.95 eV and the ODEPR spectrum labeled LEI, both of which were seen previously for electron-irradiated GaN.
Embrittlement of FE-CR-AL-ALLOYS
Authors: Lange J. H. , Brede M. , Fischer B. , Spindler S. , Wagner H. , Wittmann R. , Gerthsen D. , Broska A. , Wolff J. 
Published: April 2011

AbstractThe mechanical behavior of Fe-Cr-Al-alloys was investigated at different temperatures and after several heat-treatments in order to determine critical conditions for the ductility of the material. It was found that a significant embrittlement takes place during deformation at higher temperatures around 400 °C as well as after heat-treatments at temperatures above 1000 °C in combination with very high or very low cooling rates. Possible reasons for this behavior are discussed with respect to the results of transmission electron microscopy (TEM), Auger spectroscopy (AES), positron annihilation spectroscopy (PAS) and measurements of the electrical resistivity.
Effect of Crack Geometry on Dislocation Nucleation and Cleavage Thresholds
Authors: Fischer L.L. , Beltz G.E. 
Published: April 2011

AbstractA continuum model based upon the Peierls-Nabarro description of a dislocation ahead of a crack is used to evaluate the critical mode I loading for dislocation nucleation at the tip of a finite, pre-blunted crack. A similar approach is used to evaluate the critical mode I loading for atomic decohesion. Results are presented for various crack tip root radii (a measure of bluntness), for several crack lengths. It is shown that increasing the crack length increases the critical energy release rate for both material behaviors. Increasing the bluntness of a crack tip always increases the required loading for atomic decohesion but nucleation thresholds are initially decreased by very small increases in crack tip bluntness. Nucleation thresholds are later increased after reaching significant crack tip blunting. Implications for ductile versus brittle competition are discussed by comparing the ongoing competition between these two different material behaviors.
Transitions of Shear Resistance in a Single-Asperity Contact
Authors: Hurtado J. A. , Kim K.-S. 
Published: April 2011

AbstractThe shear force required to emit circular dislocation loops from the edge of a circular adhesive-contact zone is calculated analytically as a function of contact-zone radii. The emission condition is based on the balance of the configurational force and the Peierls force on a dislocation loop initiated at the edge of the adhesive contact zone. The analysis suggests that there is a transition, for a nanometer-scale single-asperity contact, from concurrent (mobile- dislocation-free) slip to single-dislocation-assisted (SDA) slip. The nanometer-scale friction stress (shear force required for slip/contact area), which experimentally is observed independent of normal loading and contact-zone size, is believed to be the stress required for concurrent slip. The analysis also predicts a second transition from SDA slip to multiple-dislocation-cooperated (MDC) slip at the scale of tens of micrometers in contact size. The friction stress at this large length scale has also been observed experimentally to be independent of normal loading and contact size; however, the friction stress at the nanometer scale is about 30 times that at the scale of tens of micrometers. The analysis is consistent with these experimental observations.
Characterization and Oxidation Kinetics of Reactively Sputtered Ti1−xAlxN Film
Authors: Ishizuka Yoshiki , Kim Dong Joo , Streiffer Stephen K. , Kingon Angus I. 
Published: April 2011

AbstractWe report on the use of Ti1−xAlxN as an electrically conductive barrier layer from the viewpoint of its oxidation kinetics and electrical properties. Auger electron spectroscopy depth profile analysis revealed the improvement of oxidation resistance with Al incorporation. At 650 °C, an oxygen diffusion coefficient and an activation energy of Ti0.47AI0.53N were determined to be 5.85×10−1 Å 2/sec and 2.51 eV respectively. Compared with TiN, this corresponds to an oxide gowth rate reduction of about two orders of magnitude. An Al-rich oxide layer, which gew near the Ti1−XAlxN surface, is believed to act as a passivation layer to oxidation. Furthermore, current-voltage characteristics showed that the oxidation resistant Ti1−xAlxN minimized the increase of electrical resistance after heat treatment in an oxidizing atmosphere. These results suggest that Ti1−xAlxN is an attractive candidate for an electrically conductive barrier layer for advanced memory device applications.
Influence of the substrate temperature on the structure of SrBi2Ta2O9 thin films obtained by laser ablation
Authors: Díaz J. A. , Cruz M. P. , Contreras O. E. , Siqueiros J. M. , Portelles J. 
Published: April 2011

AbstractA systematic study is presented of the resulting SBT films deposited by PLD at substrate temperatures from 300 to 600°C. The characteristics of the film as-deposited are determined. Special attention is focused on the compositional and structural properties. XRD, SEM, and TEM analyses are reported.
Effects of the Purity of Metalorganic Sources on the Electrical Properties of Pb(ZrTi)O3 Thin Films by MOCVD
Authors: Shimizu M. , Yoshida M. , Fujisawa H. , Niu H. 
Published: April 2011

AbstractEffects of the purity of metalorganic Pb,Zr and Ti precursors (Pb(C2H5)4, Zr(O-tC4H9)4 and Ti(O-iC3 H 7)4) on the electrical properties of Pb(ZrTi)O3 (PZT) thin films prepared by MOCVD were investigated. Generally, PZT thin films prepared using the high purity Pb source precursor had a tendency to show better current densities, breakdown electric fields and switching fatigue characteristics than those of PZT films prepared using the low purity precursor. On the other hand, distinct purity effects of Zr and Ti source precursors were not observed. These experimental results suggest that some types of impurities play important roles as donors and acceptors and influence ionic movement and space charge. At this stage, it is not well understood which impurities contained in precursors play important roles and what is the difference in the impurity effects between Pb, and Zr and Ti precursors.
Pulsed Laser Deposition of Piezoelectric Films for Micro-Fluidic Applications
Authors: Kim W.J. , Rife J.C. , Horwitz J.S. , Auyeung R.C.Y. , Chrisey D.B. , Bell M.I. , Smith R.W. 
Published: April 2011

AbtractThick films of piezoelectric materials have been grown by pulsed laser deposition (PLD) for use in the development of a programmable micro-fluidic controller. ZnO and BaTiO3 (BTO) films were deposited onto various substrates, including Au/Cr coated Si, Pt/Ti coated Si, and Au/Pd coated glass microchannel plates, at substrate temperatures from room temperature to 800 °C in a background pressure of O2 from 3 to 350 mTorr. ZnO films (∼5 µm thick) were single phase and (001) oriented. BTO films, 33 µm thick, on Pt/Ti/Si were single phase and polycrystalline. To fabricate piezoelectric acoustic transducer, an array of 2 × 4 gold electrodes was deposited onto the thick BTO films through a shadow mask by PLD. The transducers were attached to a simple fluidic circuit with a 1.6 × 1.6 mm cross section and used to generate a flow velocity of 1 mm/s at an operating frequency of 50 MHz.
Thermal Expansion and Glass Transition Behaviour of Thin Polymer Films with and without a Free Surface Via Neutron Reflectometry
Authors: Pochan D. J. , Lin E. K. , Satija S. , Cheng S. Z. D. , Wu Wen-Li 
Published: April 2011

AbstractThe thermal expansion of thin deuterated polystyrene (dPS) films supported on energetically repulsive, fluorinated polyimide (PI) substrates (PI/dPS bilayer) was measured via neutron reflectometry as a function of initial dPS film thickness. Film thickness was measured before and after capping with a top layer of the same repulsive, high glass transition polyimide that comprised the substrate layer (PI/dPS/PI trilayer) in an attempt to observe any effects of the dPS free surface in the bilayer geometry. Bulk thermal expansion behavior, characterized by a discontinuous change in coefficient of thermal expansion (CTE) at the glass transition (Tg), is observed in films with thickness > 70 rim. For thicknesses between 70 nm and 40 nm a transition is seen from bulk behavior in bilayer films to glassy thermal behavior in the trilayer films persisting up to 20 °C above the bulk Tg. In films with thickness < 40 nm the bulk glassy CTE persists well above the bulk Tg for both bilayer and trilayer films