bluuebunny/crossref_metadata_2025_split huggingface dataset:
Excess Vacancy Generation by Silicide Formation in Si
Authors: Jaccodine R. J. 
Published: April 2011

AbstractIt has been long recognized that excess point defects are generated when a metal silicide is formed on silicon. Since the common dopants diffuse in Si with the aid of both self-interstials and vacancies, these point defect perturbations will influence motion of diffusions that are in the adjacent vicinity. TiSi2 is known to enhance the concentration of vacancies and several mechanisms have been proposed for this effect. Recent literature has dealt with and rejected many of these ideas; however, some of the remaining few like film strain and lattice contraction upon silicidation have been the subject of state of the art experiments which has led to their rejection.It is the contention of this paper that by using the experimental data from this recent work and reinterpreting it, the model of volume contraction of the silicides as the cause for vacancy injection, still represents the most physically satisfying cause and therefore, was mistakenly rejected.
Sequential Operation of Three Distinct Misfit Dislocation Introduction Mechanisms in an Epitaxial Bilayer Film
Authors: Gopal V. , Kvam E. P. , Chen E.-H. , Woodall J. M. 
Published: April 2011

AbstractMismatch stress relaxation mechanisms in bilayer films of (In, Al)As on InAs on GaP have been examined. Initial edge (90°) misfit dislocations at the InAs/GaP interface appear to be introduced directly at island edges during initial stages of growth. The incomplete mismatch compensation is taken up by later introduction of glissile (60°) dislocations, usually in pairs which combine to form edge dislocations. The edge dislocations in the interface then move laterally to equalize their spacings. The upper (In, Al)As capping layer, which is tensile strained to match the relaxed InAs, exhibits a different mechanism of misfit dislocation introduction. Threading dislocations move by climb, directly introducing sessile edge dislocations at the buried interface. It is believed this is the first time that this mechanism has been observed.
Stress Effects in the Oxidation of Planar SiO2 Thin Films
Authors: Delph T. J. , Jaccodine R. J. 
Published: April 2011

AbstractWe summarize here the results of recent experimental and analytical investigations into stress effects in planar SiO2 thin films. Experimentally, we examine the effects of a constant superposed in-plane stress upon the growth of thin oxide films in the 100 Å range. In contradiction to a widely accepted model of stress effects upon SiO2 film growth, we find that both compressive and tensile in-plane stresses tend to retard oxide growth by a roughly equal amount. Analytically, we investigate the effects of the small component of strain induced parallel to the oxidation interface by the large volume expansion inherent in the oxidation of silicon. Depending upon the circumstances, this strain component, dubbed the “intrinsic strain”, can have a non-negligible effect upon the growth of planar oxide layers.
Processing, Microstructure, and Fracture Behavior of Nickel/ Nickel Aluminide Multilayered Thin Films
Authors: Banerjee R. , Fain J. P. , Thompson G. B. , Anderson P. M. , Fraser H. L. 
Published: April 2011

AbstractThe Ni-Ni3Al system is the basis of a large number of Ni-based superalloys used extensively in the aerospace industry. The mechanical properties of bulk superalloys, which primarily consist of a Ni-based fcc matrix reinforced with cubic precipitates of Ni3Al, have been extensively researched. The goal of the present study is to investigate the mechanical properties of multilayered Ni / Ni3Al nanocomposites in the thin film form. These multilayers have been processed using UHV magnetron sputtering by alternate deposition of pure elemental Ni and Ni-25at%Al layers in the range of 20 nm – 120 nm. By varying the substrate material and processing parameters such as deposition temperature, multilayers with two types of interfacial orientations. (111) Ni //(111) Ni3Al and (002) Ni //(002) Ni3Al have been fabricated. Microstructural and phase characterization of the multilayers in both plan-view as well as cross-section geometries have been carried out using x-ray diffraction, SEM and TEM and the results of these will be discussed. Both orientations exhibited a high density of twins lying on the {111} planes. The loss of coherency in these multilayers as a function of the layer thickness will also be discussed. The cross-section fracture behavior of these multilayers has been studied by SEM fractography. Failure mode for fracture was a result of the application of tensile stresses. Interesting effects of the interfacial orientation and the layer thickness on the fracture surface of these multilayers will be discussed.
Fatigue of Thin Silver Films Investigated by Dynamic Microbeam Deflection
Authors: Schwaiger R. , Kraft O. 
Published: April 2011

AbstractThe fatigue behavior of bilayer microbeams consisting of thin Ag films on an SiO2 substrate was investigated. The beams were cyclically deflected using a commercial nanoindentation instrument, which is capable of precise positioning of indentations. The dynamic beam stiffness is monitored continuously throughout the whole experiment. Silver was chosen as a model material for fcc metals. For large strains and/or strain amplitudes the beam stiffness decreased significantly during the fatigue tests, which is related to damage formation, as cracks and extrusions were found after the experiment. In fatigue tests at lower strains and the same number of cycles no significant stiffness change was observed. In this case only extrusions but no cracks occurred.
Mechanical Properties and Adhesion of PZT Thin Films for MEMS
Authors: Jungk J. M. , Crozier B. T. , Bandyopadhyay A. , Moody N. R. , Bahr D. F. 
Published: April 2011

AbstractPiezoelectric films are attractive materials for use in microelectromechanical systems (MEMS) due to their ability to act as both sensors and actuators. One of the primary modes of deformation is the deflection of lead zirconate titantate (PZT) beams and membranes, where the adhesion of the film is critical for the reliability of the device. Thin films of PZT between 250 and 750 nm have been grown via solution deposition routes onto platinized silicon substrates. The films have been tested using nanoindentation techniques. Two failure mechanism in these films have been observed Indentation induced delamination at the PZT-Pt interface occurs after the indenter tip is removed from the film when loads between 1 and 10 mN are applied to the sample, and at large loads (>75 mN) failure can be generated between the underlying oxide film and the silicon substrate while the tip is still engaged with the sample. Since each of these failure modes has a different mechanics solution, the results are compared to determine adhesion energy of the films. Fracture around the delaminated regions has been examined using scanning probe and electron microscopy. Freestanding PZT membranes above micromachined cavities have been mechanically deformed to examine the mechanical response and failure modes in these structures. The adhesion of the PZT improves with increased percent crystallization due to the introduction of residual tensile stresses. Processing, mechanical properties, and failure modes in these devices will be discussed.
Thermal Shock Behaviour of Thin Bi-Material Ceramic Systems
Authors: Busso E. P. , Tkach Y. V. , Travis R. P. 
Published: April 2011

AbstractThis work describes a methodology developed to predict the thermal shock behaviour of thin bi-material ceramic systems. An experimental procedure based on controlled air cooling has been devised to simulate the flow of a gas stream over the surface of a thin two-layer ceramic system. Results of microstructural and fractographic investigations conducted on tested samples, including representative fracture patterns and crack initiation sites, are presented. A probabilistic-deterministic approach to predict the thermal shock behaviour of bi-material ceramic systems is proposed. Failure diagrams are constructed from a combination of the experimental and analytical studies. Critical thermal transient conditions typical of start-up and shut-down operation in solid oxide fuel cell are determined.
Mechanical Behavior of Indium Oxide Thin Films on Polymer Substrates
Authors: Cairns D. R. , Sachsman S. M. , Sparacin D. K. , Witte R. P. , Crawford G. P. , Paine D. C. 
Published: April 2011

AbstractWe report on the change in electrical resistance of tin doped indium oxide thin films on polymer substrates with increasing uniaxial strain. The resistance increases rapidly but continuously above a threshold strain. The threshold strain at which the resistance increases is correlated to the onset of cracking in the oxide film. The strain for cracking and increase in resistance depend upon film thickness. We have measured the distance between neighboring ITO cracks as a function of strain in situ using an optical microscope. At high uniaxial strains the ITO layer fails in the orthogonal direction due to lateral contraction of the polymer substrate. The gradual increase in resistance is modeled assuming there is a conducting layer at the polymer/ITO interface.
Study of Crack Propagation at an Oxide/Polymer Interface Under Varying Loading Conditions
Authors: Panteliidis Dtmitrios , Snodgrass Jeffrey , Dauskardt Reinhold H. , Bravman John C. 
Published: April 2011

AbstractWe investigate the effect of loading conditions and process parameters on the failure mode of a Silicon/SiO2/Silane/BCB interface system. Chemical analysis of the fracture surfaces with XPS reveals different crack paths through the structure for the two different loading configurations studied. Furthermore, the curing temperature of the silane coupling agent is shown to have a profound impact on the subcritical debond behavior of the structure. A mechanism responsible for this effect is identified and the XPS data is directly correlated to quantitative information about the resistance of the structure to fracture and subcritical crack growth.
Stress Development in Low Dielectric Constant Silica Films During Drying and Heating Process
Authors: Lu Mengcheng , Brinker C. Jeffrey 
Published: April 2011

AbstractLow dielectric constant silica films are made using a surfactant templated sol-gel process (K∼2.5) or an ambient temperature and pressure aerogel process (K∼1.5). This paper will present the in-situ measurement and analysis of stress development during the making of these films, from the onset of drying till the end of heating. The drying stress is measured by a cantilever beam technique; the thermal stress is measured by monitoring the wafer curvature using a laser deflection method. During the course of drying, the surfactant templated films experience a low drying stress due to the influence of the surfactant on surface tension and extent of siloxane condensation. The aerogel films first develop a biaxial tensile stress due to solidification and initial drying. At the final stage of drying where the drying stress vanishes, dilation of the film recreates the porosity of the wet gel state, reducing the residual stress to zero. For the surfactant templated films, very small residual tensile stress remains after the heat treatment is finished (∼30MPa). Aerogel film has almost no measurable stress developed in the calcination process. In situ spectroscopic ellipsometry analysis during drying and heating, and TGA/DTA are all used to help understand the stress development.
Measurement of Local Strain in Thin Aluminium Interconnects Using Convergent Beam Electron Diffraction (CBED)
Authors: Krämer S. , Mayer J. 
Published: April 2011

AbstractEnergy filtered convergent beam electron diffraction (CBED) was used to investigate localized strain in aluminium interconnects. An analysis of the higher order Laue zone (HOLZ) line positions in CBED patterns makes it possible to measure the lattice strain with high accuracy (∼10−4) and high spatial resolution (10 to 100 nm). The strain development in a single grain was measured during thermal cycling between −170°C and + 100°C. The grain showed reversible, elastic behaviour over the whole temperature range building up large strains at low temperatures. By comparing with finite element simulations, a detailed understanding of the tri-axial strain state could be achieved.
Plastic and Elastic Behavior of Sputtered Bilayered Films by Nanoindedtation
Authors: Kikuchi N. , Kusano E. , Sawahira Y. , Kinbara A. 
Published: April 2011

AbstractDeformation behavior of sputtered Al/TiN and Cu/TiN bilayered films was examined by using dissipated and elastic energies estimated from the area enclosed by the load-displacement curve of nanoindentation. These films studied consisted of TiN top-layer of 500 nm and Al or Cu underlayer of 0 - 500 nm on glass or sapphire substrate. The dissipated energy for plastic deformation increased with increasing thickness of metal underlayer, while the elastic energy remained constant. A decrease in plastic energy was observed by changing the underlayer material from Al to Cu. Further, a reduction in elastic energy was observed when a sapphire was used as a substrate. Experimental results show that the plastic deformation mainly occurred in metal underlayer and the elastic deformation did in TiN layer and in the substrate. It was concluded that the yield stress and elastic modulus of layers and substrate strongly affect the deformation behavior of the films.
Mechanical Properties of Electroplated Copper Thin Films
Authors: Spolenak R. , Volkert C. A. , Takahashi K. , Fiorillo S. , Miner J. , Brown W. L. 
Published: April 2011

AbstractIt is well known that the mechanical properties of thin films depend critically on film thickness However, the contributions from film thickness and grain size are difficult to separate, because they typically scale with each other. In one study by Venkatraman and Bravman, Al films, which were thinned using anodic oxidation to reduce film thickness without changing grain size, showed a clear increase in yield stress with decreasing film thickness.We have performed a similar study on both electroplated and sputtered Cu films by using chemical-mechanical polishing (CMP) to reduce the film thickness without changing the grain size. Stress-temperature curves were measured for both the electroplated and sputtered Cu films with thicknesses between 0.1 and 1.8 microns using a laser scanning wafer curvature technique. The yield stress at room temperature was found to increase with decreasing film thickness for both sets of samples. The sputtered films, however, showed higher yield stresses in comparison to the electroplated films. Most of these differences can be attributed to the different microstructures of the films, which were determined by focused ion beam (FIB) microscopy and x-ray diffraction.
Hall-Petch Hardening in Pulsed Laser Deposited Nickel and Copper Thin Films
Authors: Knapp J. A. , Follstaedt D. M. , Banks J. C. , Myers S. M. 
Published: April 2011

AbstractVery fine-grained Ni and Cu films were formed using pulsed laser deposition onto fused silica substrates. The grain sizes in the films were characterized by electron microscopy, and the mechanical properties were determined by ultra-low load indentation, with finite-element modeling used to evaluate the properties of the layers separately from those of the substrate. Some Ni films were also examined after annealing to 350 and 450°C to enlarge the grain sizes. These preliminary results show that the observed hardnesses are consistent with a simple extension of the Hall-Petch relationship to grain sizes as small as 11 nm for Ni and 32 nm for Cu.
The Microstructure and Nanoindentation Behaviour of TiN/NbN Multilayers
Authors: Molina-Aldareguia J. M. , Lloyd S. J. , Barber Z. H. , Blamire M. G. , Clegg W. J. 
Published: April 2011

AbstractTiN/NbN multilayers and TiN monolithic films have been grown by UHV reactive magnetron sputter deposition on MgO single crystals. The hardness has been measured by nanoindentation and the as-deposited and deformed structures studied in cross-section using transmission electron microscopy. It has been found that initially the multilayers grow epitaxially with the substrate. However, once the overall film thickness has reached ∼300 nm, epitaxial growth ceases. No increase in hardness with respect to monolithic films of the multilayer components is observed in these multilayers. Experiments on monolithic films of TiN show that the same loss of epitaxy occurs, leading to a reduction in the hardness of the films, and that this change in growth morphology is triggered by the internal stresses induced within the films during deposition.
Pt Film Growth with Tetra-Kis(Triflurophosphine)Platinum
Authors: Sun Y.-M. , Lozano J. , Mettlach N. , Ekerdt J. G. , Madhukar S. , Hance R. L. , White J. M. 
Published: April 2011

AbstractPlatinum film growth using Pt(PF3)4 precursors was investigated. The study focused on three aspects of film growth: conformality, adhesion and selective growth. Pt(PF3)4 deposited pure Pt films over a wide range of temperatures (∼200 to 400 °C). At 200 °C, the step coverage for a via with an aspect ratio of three was poor. Lower growth temperatures showed a significant decrease in the growth rate. In addition, these films had poor adhesion to the substrate as indicated by separation between the Pt and the substrate in cross sectional scanning electron microscopy images. Oxygen addition during Pt film growth from Pt(PF3)4 improved both film conformality and adhesion. With oxygen, the step coverage on the side wall was greater than 90 % The dependence of the film growth rate on oxygen varied with the growth temperature: the growth rate decreased at 200 °C, while it changed slightly at 260 °C when oxygen was added. The substrate effect on the initial growth rate was studied on various substrates. The initial growth rate on metals is much faster than that on other substrates. The growth rate decreased on various substrates in the order of iridium > titanium nitride > barium strontium titanate > silicon nitride > silicon oxide.
Integration Issues of (Ba,Sr)TiO3Thin Films in High Density Devices
Authors: Yoo C. Y. , Park H. B. , Hwang D. S. , Hideki H. , Kim W. D. , Lim H. J. , Lee B. T. , Park Y. W. , Lee S. I. , Lee M. Y. 
Published: April 2011

AbstractRecent progress to overcome integration issues related with (Ba,Sr)TiO3 films are presented. Firstly, ternary barrier material, Ti0.7Al0.3N deposited by reactive sputtering is shown to have superior oxidation resistance than TiN through the test using contact string pattern where Pt is deposited as a electrode. Ti0.7Al0.3N barrier is able to keep stable contact resistance below 100Ω even under oxidizing condition where the temperature is 550°C and oxygen partial pressure is 7.6 Torr. If rapid thermal annealing is used, annealing temperature without oxidation of Ti0.7Al0.3N can be increased by about 100°C. Ti0.7Al0.3N is thought to be the promising one which can endure during post-annealing process. Secondly, electroplating technology is employed to fabricate the stack capacitor of Pt that has been known to be very difficult to etch. 500Å-thick Pt is used as a seed layer and very thick Pt is selectively grown on the seed layer by the electroplating. The Pt height can be controlled by changing the electroplating time, so we can make stack Pt over 8000Å. Thirdly, low temperature deposition process for MOCVD BST film is developed. The equivalent oxide thickness of about 3.5Å is obtained on Pt electrode when BST thickness is 150Å. BST film is deposited at 420°C and annealed at 700°C under oxidizing atmosphere. It is suggested that a new two step annealing consisting of high temperature annealing under inert atmosphere and low temperature annealing under oxidizing atmosphere is very effective to achieve the high dielectric constant and low leakage current of BST films at the same time. It is also adequate for preventing the barrier oxidation. BST film with Toxeq. of 5.2Å and low leakage current is obtained by annealing at 650°C under N2 followed by annealing at 550TC under O2. Electrical properties of BST deposited on side-wall of Pt concave capacitor is evaluated. The concave capacitor with about aspect ratio 3 shows the same capacitance and leakage current as the planar capacitor, which implies that BST composition and thickness is uniform on the side-wall. It is concluded that BST films on Pt electrode can be applied to real device.
MOCVD of Nb Substituted SrBi2Ta2O9 for Integrated Ferroelectric Capacitors
Authors: Hendrix B. C. , Glassman T. E. , Roeder J. F. 
Published: April 2011

AbstractThe Bi layered perovskites are promising materials for ferroelectric random access memories (FeRAM's) because of their inherently high resistance to fatigue. Liquid delivery, flash vaporization metalorganic chemical vapor deposition (LD-MOCVD) is an attractive process for these materials, because it offers the ability to produce high quality, conformal films of controlled composition for both high and low density memory applications. We have developed a well-controlled process to deposit Nb-substituted SrBi2Ta2O9 (SBNT) using a mixed alkoxide-β-diketonate precursor Nb(O-i-Pr)4(thd) that is compatible with a previously developed precursor suite for SBT (Sr(thd)2-pmdeta, Bi(thd)3, and Ta(O-i-Pr)4(thd)). The Nb and Ta precursors behave in the same way in the process, making the Nb substitution level in the film identical to that in the precursor solution. In this study, wavelength dispersive x-ray fluorescence has been used to characterize composition and thickness. As-deposited films are smooth, with a surface roughness of 2 nm RMS. After a post-deposition annealing treatment, a high quality layered perovskite crystal structure was obtained. The resultant ferroelectric hysteresis shows a 50% increase in coercive voltage for 28% Nb substitution at the Ta site with the same switchable polarization. In the 28% Nb containing film, imprint was significantly improved compared to SBT films without substitution.
Effect of Film Composition on Low Temperature Processing of SBT Deposited by MOCVD
Authors: Bachhofer Harald , Hintermaier Frank , Hauf Manfred , Spindler Oswald , Haneder Thomas , Dehm Christine , von Philipsborn Henning , Waser Rainer 
Published: April 2011

AbstractBi-layered ferroelectric strontium bismuth tantalate (SBT) thin films of various film compositions were deposited on Pt/Ti/SiO2/Si substrates by metalorganic chemical vapor deposition (MOCVD) and crystallized at 700°C in oxygen ambient. Phase transition, orientation, second phases and remanent polarization were investigated with respect to film stoichiometry. X-ray diffraction (XRD) measurements revealed that excess Bi lowers the transition temperature from fluorite-type to ferroelectric phase. However, SBT films with Bi-excess of 15% or higher exhibit pronounced Bi-loss during crystallization and a decrease in the relative intensity of the (200) peak. Highly Sr-deficient films are not fully crystallized but support pyrochlore formation. The maximum remanent polarization is obtained at a Sr-deficiency of 15–25% and a Bi-excess of 10% (0.85/2.20/2.00).