bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improvement of the ITO-p Interface In a-SI:H Solar Cells Using a Thin SiO Intermediate Layer
Authors: Carvalho C. Nunes De , Nijs J. M. M. De , Ferreira I. , Fortunato E. , Martins R. 
Published: April 2011

AbstractThe use of ITO thin films on glass/ITO/p-i-n/metal amorphous silicon solar cells is reviewed. It is suggested a new application for silicon monoxide thin films on the ITO-p interface, as an intermediate layer, to minimize the fTO thin film deterioration process, during the early stage of exposure to a silane plasma rich in hydrogen. The thickness of the silicon monoxide thin films is chosen not to worsen the optical and electrical properties of the ITO thin films. The TO-p interface is optimized (due to impurities diffusion decrease), leading to an overall improvement of the device performance.
Study of ZnTe:Cu Back Contacts on CdTe/CdS Thin Film Solar Cells
Authors: Tang J. , Feng L. , Mao D. , Song W. , Zhu Y. , Trefny J. U. 
Published: April 2011

AbstractVacuum-evaporated Cu-doped ZnTe films have been studied as the intermediate layer between CdTe and metal contacts in CdTe/CdS thin-film solar cells for the formation of low resistance back contacts. Different metals (Au, Ni, Co) have been investigated as the contact material to the ZnTe layer. The effects of Cu concentration, ZnTe:Cu layer thickness, and ZnTe post-deposition annealing temperature on the cell performances have been investigated. We found that different metal contacts on the ZnTe layer lead to different doping densities in the CdTe layer and different open-circuit photovoltages of the solar cells. The possible formation of a back contact diode at the CdTe/ZnTe interface was explored, based on capacitance-voltage analysis. The series resistance of the CdTe/CdS cells was reduced significantly by the introduction of the ZnTe layer. Fill factors greater than 0.76 and an energy conversion efficiency of 12.9% have been achieved using ZnTe back contacts on electrodeposited CdTe.
Duty Cycle and Frequency Effects of Pulsed-DC Currents on Electromigration-Induced Stress in Al Interconnects
Authors: Frankovic Richard , Bernstein Gary H. 
Published: April 2011

AbstractThe effects of the duty cycle and frequency of a pulsed-current stress on the critical length-current density product, (jlc) were measured using edge-displacement techniques. In our study, Al edge-displacement segments were stressed at a temperature of 200 °C and at peak pulsed-dc current densities below 6×105 A/cm2 in a nitrogen ambient. jlc was measured for duty cycles of 25%, 50%, 75% and 100% at 100 kHz, and for 50% duty cycle at lower frequencies. jlc was observed to increase with decreasing duty cycle and increasing frequency. We measured a 2.6-fold increase in jlc for the 25% duty cycle at 100 kHz as compared to dc. We have used the vacancy supersaturation model to predict the jlc enhancement for lower duty cycle operation.
Grain-Boundary Slit Propagation in an Electric Field
Authors: Klinger L. M. , Chuj X. , Bauer C. L. , Mullin W. W. 
Published: April 2011

AbstractPropagation (advancement) of a fine slit along a planar grain boundary in an electric field E0, applied parallel to the slit, is investigated by considering electromigration along both the grain boundary and the slit surface. Steady-state solutions of the transport equations are classified according to the value of a parameter β, which, under reasonable assumptions, depends on material constants only: for 5π/4 ≥ β > β2, unique steady-state solutions exist, for β2 > β > β1, multiple steady-state solutions exist, and for β1 ≥ β ≥ π/4, no steady-state solutions exist. For all steadystate solutions, slit width and tip velocity v scale as and , respectively. Generally, v can approach 1 nm/s (3.6 μm/h), thereby representing a likely failure mechanism in fine-line (near bamboo structure) interconnects.
Microscopic Estimates for Electromigration Velocities of Intragranular Voids in Thin Aluminum Lines
Authors: Wickham L. K. , Sethna J. P. 
Published: April 2011

AbstractWe explore the effect of faceting on possible mechanisms for mass transport around electromigration voids in aluminum interconnects. Motivated by linear response estimates which suggest that particle flux would be much higher along steps than across terraces on a clean aluminum surface, we study step nucleation in the presence of a small driving force along a surface. We find that step nucleation, even on a nearly defect-free void surface, would be slow if the step energy is equal to that calculated for a clean aluminum surface. In the presence of a uniform electromigration force, the creation of new steps between existing ones should not occur unless the free energy cost of a step is much less than thermal energies. We conclude that voids cannot move intragranularly at μm/hr rates without help from other factors such as local heating and impurities.
Copper Migration and Precipitate Dissolution in Aluminum/Copper Lines During Electromigration Testing
Authors: Shaw T. M. , Hu C -K. , Lee K. Y. , Rosenberg R. 
Published: April 2011

AbstractWe have used transmission electron microscopy to examine in detail how microstructural changes take place in aluminum/copper lines adjacent to tungsten contacts. A structure that could be powered in a probe station was deposited directly on an electron transparent silicon nitride window to allow direct observation of the structure of the line after different intervals of electromigration testing. Observations made on aluminum-4% copper lines show that significant changes in the grain structure surrounding precipitates occur during testing even under conditions where no normal grain growth is observed in the lines. Elecromigration testing at 260°C resulted in grain coarsening and the formation of new diffusion blocking structures in the lines. By making measurements of the volume of individual precipitates as a function of time, the flux of copper through specific segments of the microstructure of the line could be measured. The results indicate that the presence of a single grain boundary can increase the electromigration flux of copper along the line by an order of magnitude. In line segments where a bamboo grain occurred copper diffusion appears to be controlled by diffusion along the Al/oxide interface at the surface of the lines. It is also shown that, in polycrystalline lines, the rate of copper depletion frorr the cathode is largely determined by the rate of dissolution of the precipitates. In mixed structure lines the migration of copper can become quite complex as changes in diffusion paths can occur as precipitates dissolve or grow.
Oxidation Resistance of Copper Alloy Thin Films Formed by Chemical Vapor Deposition
Authors: Atanasova P. , Bhaskaran V. , Kodas T. , Hampden-Smith M. 
Published: April 2011

AbstractCo-deposition of copper-palladium alloy films was demonstrated using low-pressure CVD from individual precursors - (hexafluoroacetylacetonato)copper(I)(vinyltrimethylsilane) [(hfac)Cu(I)vtms] and palladium(II)bis(hexafluoroacetylacetonate) [Pd(hfac)2], for Cu and Pd respectively. High-purity alloy films with controlled composition, microstructure and morphology were prepared and their oxidation behavior was examined at different temperatures and compared with that of pure copper CVD films with similar morphology. As-deposited copper-palladium alloy films showed improved resistance to oxidation up to 300°C in air. Enhanced oxidation resistance compared to Cu CVD films was observed at concentrations of palladium as low as 0.5 at. %.
Building in Reliability Through a 100x Reduction in Mobile Ions in a 0.8 μm BiCMOS Process
Authors: Anderson Larry , Parikh Suketu , Nagalingam Samuel 
Published: April 2011

AbstractThe reduction of mobile ions--mainly Na+, but also K+, H+ and Li+, is very critical as our gate oxide thickness and Leff decreases. Hot electron induced hydrogen compensation of boron doped silicon changes the PMOS Leff and NPN BVebo. This paper shows how to reduce Na+ by 100X, through the use of Triangular Voltage Sweep (TVS). This paper is designed to give scientists and engineers a case history where we reduced these levels from 1012 to 1010 mobile ions/cm2 in our 0.8μm BiCMOS process. This was accomplished by adding Ammonium Fluoride mixture dips at appropriate steps. For fast feedback, we can non-destructively measure Na, K, and H within 10 minutes of completing phororesist removal at any of the metallization steps using TVS. In addition to BiCMOS, TVS measure is a power tool in Nonvolatile Memories for predicting in-line data retention, when data retention is associated with charge gain.
Void-Free Metallization By Controlling Sputtering Conditions Of Tin Barrier Metal Films
Authors: Yamaoka T. , Yamauchi T. 
Published: April 2011

AbstractProduction Engineering R‘‘void-free’ metallization is proposed. It is shown that void formation is suppressed when the TiAl3 intermediate layer is formed at the interface between the Al alloy and reactively sputtered TiN barrier metal films. We have investigated the relationship between void formation and coverage of the intermediate layer. It is found that a coverage of more than 60 % TiAl3 perfectly suppresses void formation. The interfacial reaction is achieved by using ‘soft TiN', which arises from the short migration length of the sputtered particles impinging on the substrate surface when dc power is decreased. The soft TiN film includes many vacancies and crystallographically disordered regions which easily cause rearrangement of the TiN films by movement of Ti atoms during annealing. It is thought that these Ti atoms compensate vacancies in the Al-Si-Cu film and suppress the formation of Al voids.
Effects of a Post-Emitter RTP on Bipolar NPN Beta Degradation Lifetime for 1.0 Micron & 0.8 Micron BICMOS Processes
Authors: Leitz W. E. , Modi G. , Parekh N. , Sabin E. , Taylor R. V. 
Published: April 2011

AbstractRapid Thermal Processing (RTP) has sometimes been used to increase bipolar NPN Beta (Hfe, or current gain) for a polysilicon emitter BICMOS process. It has been demonstrated that Beta may be increased by 20%, compared to normal non-RTP process values, by the addition of an RTP cycle after the final high temperature furnace step. In our work it was found that emitter-base reverse bias degrades Beta much more severely for a process which uses RTP, than for a non-RTP process. In this paper we will report on the electrical performance effects of RTP on a variety of process parameters. The reliability effects on NPN Beta degradation lifetime, and NMOS reliability effects will be discussed as well.
Microwave Melting of Ion-Conducting Glasses
Authors: Duval D. J. , Terjak M. J. E. , Risbud S. H. , Phillips B. L. 
Published: April 2011

AbstractGlasses of the system AgI-Ag2O-(0.95B2O3:0.05SiO2) have been formed by microwave processing using a domestic multi-mode oven operating at 900 watts and 2.45 GHz. Microwave heating resulted in rapid melting times with homogeneity in the quenched glasses equivalent to or better than conventional melting at 730°C. The glass forming region in this pseudo-ternary system is compared with the conventionally melted glass forming region in the system AgI-Ag2O-B2O3. A reversible color difference has been observed between glasses conventionally melted and those melted by microwave for all glass compositions in our system.
Complex Permeability Measurements of Microwave Ferrites1
Authors: Geyer Richard G. , Krupka Jerzy 
Published: April 2011

AbstractA rigorous and accurate method for the experimental determination of the complex permeability of demagnetized ferrites at microwave frequencies is presented. The measurement uses low- loss dielectric ring resonators, is nondestructive, and allows complex permeability characterization of a single ferrite sample to be performed at frequencies from 2 GHz to 25 GHz. A wide variety of ceramic microwave ferrites having various compositions and differing saturation magnetizations were measured in the demagnetized state. Generally, at any frequency greater than gyromagnetic resonance, the real part of the complex permeability increases as saturation magnetization increases.For the same frequency magnetic losses increases as saturation magnetization increases. The real permeability results are compared with magnetostatic theoretical predictions. Measurement data show excellent agreement with theoretical predictions, but only when 2πγMs/ω < 0.75, where γ is the gyromagnetic ratio, Ms is saturation magnetization, and ω is the radian rf frequency.
Microwave Dielectric Properties, Thermal Analyses And Chemical Composition Of Heavy Clay Bodies
Authors: Tayler Garth , Hamlyn Michael , Anderson Michael 
Published: April 2011

AbstractTo investigate the suitability of heavy clay bodies for microwave processing, a range of material properties needed to be investigated.This paper presents results of the analyses, chemical, mineralogical and thermal, of a range of heavy clay bodies. The microwave dielectric properties of these bodies were measured, over a range of temperatures, using the cavity perturbation technique. The relationship between the dielectric properties and the results of DTA/TGA analysis is discussed and related to the potential use of microwave energy for the firing of these materials.
The MiRa/THESIS3D-Code Package for Resonator Design and Modeling of Millimeter-Wave Material Processing
Authors: Feher L. , Link G. , Thumm M. 
Published: April 2011

AbstractPrecise knowledge of millimeter-wave oven properties and design studies have to be obtained by 3D numerical field calculations. A simulation code solving the electromagnetic field problem based on a covariant raytracing scheme (MiRa-Code) has been developed. Time dependent electromagnetic field-material interactions during sintering as well as the heat transfer processes within the samples has been investigated. A numerical code solving the nonlinear heat transfer problem due to millimeter-wave heating has been developed (THESIS3D-Code). For a self consistent sintering simulation, a zip interface between both codes exchanging the time advancing fields and material parameters is implemented. Recent results and progress on calculations of field distributions in large overmoded resonators as well as results on modeling heating of materials with millimeter waves are presented in this paper. The calculations are compared to experiments.
Kinetics of the Carbon Monoxide Oxidation Reaction Under Microwave Heating
Authors: Perry W. Lee , Katz Joel D. , Rees Daniel , Paffett Mark T. , Datye Abhaya 
Published: April 2011

Abstract915 MHz microwave heating has been used to drive the CO oxidation reaction over Pd/Al2O3 without significantly affecting the reaction kinetics. As compared to an identical conventionally heated system, the activation energy, pre-exponential factor, and reaction order with respect to CO were unchanged. Temperature was measured using a thermocouple extrapolation technique. Microwave-induced thermal gradients were found to play a significant role in kinetic observations.
Kinetics of Reduction of Iron oxides Using Microwaves as Power Source
Authors: Gomez I. , Aguilar J. , Gonzalez M. , Morales J. 
Published: April 2011

AbstractThis work deals with kinetic description of carbothermic reduction of iron oxides using microwaves as power source. Previous researches shown that it is possible to conduct this kind of processes successfully, but real kinetic comparisons between conventional and microwaves procedure have been presented partially. The aim of this work is to describe reduction kinetics, taking into account how the iron oxide is reduced by microwaves compared with conventional energy supply. In this study we used iron ore in pellet shape and dust. We found that both, pellet and dust reduction stops when it reaches approximately 40%, even at whole power
Modeling of Damage Evolution During Ion Implantation Into Silicon: A Monte Carlo Approach
Authors: Tian S. , Morris M. , Morris S. J. , Obradovic B. , Tasch A. F. 
Published: April 2011

AbstractWe present for the first time a physically based ion implantation damage model which successfully predicts both the as-implanted impurity range profiles and the damage profiles for a wide range of implant conditions for arsenic, boron, phosphorus, and BF2 implants into single-crystal (100) silicon. In addition, the amorphous layer thicknesses predicted by this damage model for high dose implants are also generally in excellent agreement with experiments. This damage model explicitly simulates the defect production and its subsequent evolution into the experimentally observable profiles for the first time. The microscopic mechanisms for damage evolution are further discussed.
Microstructural Observation of Focused Ion Beam Modification of Ni Silicide/Si Thin Films
Authors: Tanaka Miyoko , Furuya Kazuo , Saito Tetsuya 
Published: April 2011

AbstractFocused ion beam (FIB) irradiation of a thin Ni2Si layer deposited on a Si substrate was carried out and studied using an in-situ transmission electron microscope (in-situ TEM). Square areas on sides of 4 by 4 and 9 by 9 μm were patterned at room temperature with a 25keV Ga+-FIB attached to the TEM. The structural changes of the films indicate a uniform milling; sputtering of the Ni2Si layer and the damage introducing to the Si substrate. Annealing at 673 K results in the change of the Ni2Si layer into an epitaxial NiSi2 layer outside the FIB irradiated area, but several precipitates appear around the treated area. Precipitates was analyzed by energy dispersive X-ray spectroscopy (EDS). Larger amount of Ni than the surrounding matrix was found in precipitates. Selected area diffraction (SAD) patterns of the precipitates and the corresponding dark field images imply the formation of a Ni rich silicide. The relation between the FIB tail and the precipitation is indicated.
Electrical Resistivity of Copper Films by Partially Ionized Beam Deposition
Authors: Han S. , Yoon K. H. , Kim K. H. , Jang H. G. , Choi S. C. , Jung H. J. , Koh S. K. 
Published: April 2011

AbstractCopper films on Si(100) were prepared by partially ionized beam at 0 kV and 3 kV acceleration voltages in order to investigate effects of ion energy on electrical property with thickness. X-ray diffraction(XRD) pattern analysis was used to investigate crystallinity of the copper films, microstructure by Scanning electron microscope(SEM) and surface roughness by atomic force microscopy(AFM). The crystallinity of the copper films grown at the 3 kV was more (111) textured than that at the 0 kV. The copper films grown at the both conditions had nearly same grain size below a thickness of 1000 Å. The 1800 Å Cu film grown at the 3 kV was 3 times rough than that at the 0 kV. The resistivity of copper films increased due to surface and grain boundary scattering, and the change of resistivity was discussed in terms of surface roughness, grain size and film density assisted by average depositing energy.
Thermal Stability of Cu Films on Tin/Ti/Si(100) by Partially Ionized Beam Deposition
Authors: Jang H. G. , Kim K. H. , Choi D. J. , Han S. , Choi S. C. , Choi W. K. , Jung H-J. , Koh S. K. 
Published: April 2011

AbstractCu thin films with a thickness around 850 Å were prepared on Ti45N55/Ti/Si(100) substrates at room temperature by partially ionized beam deposition (PIBD) with an ion energy of 3 keV at pressure of 8×10−7–1 × 10−6 Torr. The Cu/Ti45N55/Ti/Si samples were annealed at 8× 10−6–1 × 10−5 Torr with annealing temperature of 500 to 700 °C for 30 min.. Thermal stability of the PIB-Cu films was investigated with Rutherford backscattering spectrometry (RBS), Auger electron spectroscopy (AES), Scanning electron microscopy (SEM), and X-ray diffraction (XRD).The as deposited Cu films had a (111) texture and there was no change of phase in annealed Cu films regardless of annealing temperature. Grain size of the annealed Cu films increased with annealing temperature. SEM studies show no hillock and no voiding on the Cu film surface up to annealing temperature of 700 °C. For PIB-Cu/Ti45N55/Ti/Si samples, all the layers were intact and there was no indication of interdiffusion by conventional depth profiling techniques (RBS, AES) up to 700 °C in vacuum for 30 minutes.
In Situ Ion Beam Research In Argonne's Intermediate Voltage Electron Microscope
Authors: Allen Charles W. , Ryan Edward A. 
Published: April 2011

AbstractSince Fall 1995, a state-of-the-art intermediate voltage electron microscope (IVEM) has been operational in the HVEM-Tandem Facility with in situ ion irradiation capabilities similar to those of the HVEM of the Facility. A 300 kV Hitachi H-9000NAR is interfaced to the two ion accelerators of the Facility, with a demonstrated point-topoint spatial resolution for imaging of 0.25 nm with the ion beamline attached to the microscope. The IVEM incorporates a Faraday cup system for ion dosimetry with measurement aperture 6.5 cm from the TEM specimen, which was described in Symposium A of the 1995 MRS Fall Meeting. The IVEM is now employed for a variety of in situ ion beam studies ranging from low dose ion damage experiments with GaAs, in which damage zones individual displacement cascades are observed, to implantation studies in metals, in which irradiation-induced noble gas precipitate mobility is studied in real time. In this presentation, the new instrumentation and its specifications will be described briefly, several basic concepts relating to in situ experiments in transmission electron microscopes will be summarized and examples of in situ experiments will be presented which exploit the experimental capabilities of this new user facility instrumentation.
Plastic Flow Induced by Single Ion Impacts on Gold
Authors: Birtcher R. C. , Donnelly S. E. 
Published: April 2011

AbstractIn situ transmission electron microscopy has been used to follow room temperature irradiation of thinned bulk and 62 nm thick gold films with Xe ions in the energy range 50 to 400 keV. Energy spikes resulting from single ion impacts give rise to surface craters and holes which exist until annihilation by subsequent ion impacts. Video recording provided details with a time-resolution of 33 milliseconds. Craters were produced on the irradiated surface at all ion energies and on the opposite surface when the ions had sufficient energy to traverse the specimen. Crater sizes were as large as 12 nm for the higher energy irradiations. On average, approximately 6% of impinging ions result in craters.A single 200 keV Xe ion may produce a hole in thin gold foils. Hole formation involves the movement by plastic flow of massive amounts of material; on the order of tens of thousand Au atoms per ion impact. Individual ion impacts also result in a filling of both holes and craters as well as a thickening of the gold foil. Change in morphology during irradiation is attributed to a localized, thermal-spike induced melting, coupled with plastic flow under the influence of surface forces.
Specific Effects of the Displacement Cascades on the Kinetics of Precipitation of Copper in Iron
Authors: Barbu A. , Lesueur D. , Dural J. 
Published: April 2011

AbstactIn order to probe the possibility of simulating irradiation effects with swift ions and obtaining some insight about the production rate of freely migrating defects in iron, we studied the kinetics of copper precipitation in FeCu1.34at% irradiated at 300°C with 202 MeV O- ions and 2.5 MeV electrons. The precipitation kinetics are studied in situ (GANIL for O- ions and Van de Graaff for electrons) by measuring the electrical resistivity at 30°C to reduce the phonon component. We found that, in both cases, the resistivity versus fluence (in dpa) curves are identical. This would imply either that the relatively small cascades induced by 202 MeV O- ions (compared with those produced by neutrons) are very efficient in producing freely migrating point defects or that the energy deposition by electronic excitations plays an important role. We show that this latter possibility is not relevant for 202 MeV O18 ions.