bluuebunny/crossref_metadata_2025_split huggingface dataset:
Residual Stress Effects in the Scratch Adhesion Testing of Tantalum Thin Films
Authors: White Richard L. , Nelson John , Gerberich William W. 
Published: March 2011

ABSTRACTThe effect of residual stress on the scratch adhesion critical load has been measured for sputtered tantalum films. In this single metallurgical system, six different failure modes could be observed, ranging from ductile ploughing to extensive spallation. For tantalum films deposited on silicon substrates, a 15% decrease in critical load was observed as the film residual stress increased from -1.1 GPa to +1.0 GPa. A larger percentage decrease (50%) was observed for films deposited on softer AIMg/NiP substrates. Film spallation was more extensive for films deposited over a thin carbon layer and for these films critical loads increased slightly with film stress. These results are substantially in contradiction with existing quantitative models for the scratch adhesion test and indicate that failure by shear at the film-substrate interface can be more important than failure by compressive buckling.
The Analysis of Depth-Sensing Indentation Data
Authors: Baker Shefford P. 
Published: March 2011

ABSTRACTCommon methods for analyzing depth-sensing indentation data are briefly reviewed and an overview of the principal factors limiting the accuracy and precision of results obtained using these methods is presented. The largest deviations from the elastic contact models used to interpret depth-sensing indentation data arise from time-dependent displacements and uncertainties in the shape of the indenter tip, the elastic/plastic nature of the contact and the compliance of the testing machine.
Growth Stress in CVD-WGex Films Deposited by Reduction of WF6 by GeH4
Authors: Leusink G.J. , Oosterlaken T.G.M. , Janssen G.C.A.M. , Radelaar S. 
Published: March 2011

ABSTRACTGrowth stresses in thin metal films on a substrate are important for integrated circuit device fabrication and reliability. The development of growth stress in blanket CVD-WGex films deposited by GeH4 reduction of WF6 is studied by in situ wafer curvature measurements. Depending on process conditions, the growth stress varies from 600 MPa tensile in β-WGex films deposited at low temperatures (T < 400 °C) to 400 MPa compressive in α-WGex films deposited at high temperatures (T > 400 °C). At very low temperatures amorphous WGex films grow without significant stress. Development of tensile growth stress is favoured by low temperatures and high growth rates, whereas development of compressive growth stress is favoured by high temperatures and low growth rates. Although the material properties of CVD-WGex films depend on process conditions, the development of growth stress in these films shows a dependence on deposition temperature and growth rate which is similar to pure α-W films deposited by H2 reduction of WF6. The results will be discussed in view of a model which has recently been put forward to explain development of growth stress in polycrystalline metal films on a substrate.
Dispersion Strengthening of AL Films by Oxygen Ion Implantation
Authors: Bader S. , Flinn P.A. , Arzt E. , Nix W.D. 
Published: March 2011

ABSTRACTFinely dispersed, stable Al-oxide particles were produced in Al films on Si substrates by oxygen ion implantation . A laser reflow technique was employed to vary the grain structure of some of the films. Transmission electron microscopy (TEM) was used to characterize the oxide particles and the grain size in the films, and a wafer curvature technique was employed to study the influence of microstructure on the deformation properties as a function of temperature.For coarse grained laser reflowed films, ion implantation increased the strength considerably, both in compression and in tension. Weak beam TEM techniques showed that the strengthening is most likely caused by attractive interactions between dislocations and particles. As-deposited and ion implanted films showed a stable grain size of only 0.35 μm after annealing, which caused significant softening to occur in compression, especially at high temperature. However these films showed very high stresses in tension at temperatures below 130°C. In these films the presence of the oxide particles stabilizes the small grain size and this causes a weakening effect which can be attributed to diffusion controlled grain boundary relaxation mechanisms. The high tensile stresses at temperatures below 130°C can be explained by direct and indirect particle strengthening.
Dislocation Threading Through an Epitaxial Film: an Analysis Based on the Peierls-Nabarro Concept
Authors: Beltz G. E. , Freund L. B. 
Published: March 2011

ABSTRACTThe Peierls-Nabarro theory of crystal dislocations is applied to estimate the critical thickness of a strained layer bonded to a substrate for a given mismatch strain. Previous analyses were based on the continuum theory of elastic dislocations, and hence depended on the artificial core cutoff parameterr0. The Peierls-Nabarro theory makes use of an interplanar shear law, which leads to a more realistic description of the stresses and displacements in the vicinity of a dislocation core, thus eliminating the need for the core cutoff parameter. The dependence of the critical layer thickness on the mismatch strain in films with a diamond cubic lattice is found to be similar to that predicted by the continuum elastic dislocation theory, provided that a core cutoff radius equal to about one-tenth the Burgers displacement is used.
Indentation Creep Studies of Cross-linked Glassy Polymer Films
Authors: O'Connor Kevin M. , Cleveland Pamela A. 
Published: March 2011

ABSTRACTIndentation creep testing was done on cross-linked glassy polymers based on polystyrene, specifically poly(styrene-co-divinylbenzene) (PS-DVB) and poly(divinylbenzene) (PDVB). The continuous depth-sensing capabilities of the Nano-Indenter II were used to measure the time-dependent response to indentation at constant applied load. The raw creep data in terms of indentation depth vs time showed that PDVB was about 20% more resistant to penetration than PS-DVB. A data analysis program was developed that converted the raw data to stress σ and plastic strain rate ε and generated the plastic flow curve that was observed to follow the power law . The stress exponent a for PS-DVB increased with applied loads between 1 and 27 mN and was generally larger in magnitude than the exponent for PDVB. When compared at equivalent stress and indentation depth, the plastic strain rate for PDVB was observed to be about 100 times slower than for PS-DVB. This was attributed to the higher degree of cross-linking increasing the characteristic relaxation time governing creep flow in these polymers.
Elastic Properties of a Polyimide Film Determined by Brillouin Scattering and Mechanical Techniques
Authors: Sai Kumar R. , Schuller Ivan K. , Kumar Sudha S. , Fartash A. , Grimsditch M. 
Published: March 2011

ABSTRACTWe discuss here the complete determination of the elastic properties of a polyimide film using two experimental techniques. One technique employs the polymer film as a vibrating membrane and allows a direct determination of the ’macroscopic’ biaxial modulus. Brillouin scattering, which measures the elastic properties on a ∼ 100 μ scale, allows for a complete characterization of the elastic behavior. The results obtained by the two techniques are in agreement within the reported error bars.
Continuous Microindentation of Passivated Surfaces in Surface Active Media
Authors: Venkataraman Shankar K. , Huang He , Kohlstedt David L. , Gerberich William .W. 
Published: March 2011

ABSTRACTContinuous microindentation tests on electropolished, single crystal Fe(3wt%Si) and Ni surfaces with thin passivation layers exhibit sharp discontinuities in the load-displacement behavior. At the discontinuity, which occurs at a load of 1.8 mN for Fe(3wt%Si) and 0.1 mN for Ni, stresses below the indenter were close to the theoretical strength of the corresponding metal. Microindentation tests performed to loads less than the discontinuity point showed an elastic load-unload behavior. On removing the passive film with a NaCl or HC1 solution, strengths are one to two orders of magnitude smaller in the presence of the chloride ions. On evaporation of the liquid, the load at the discontinuity returned to its initial value due to repassivation, indicative of a passivation oxide layer with varying thickness. This conclusion was verified by ellipsometry. Even though the elastic load-unload behavior on the passivated surface suggests elastic behavior, both elastic finite element and non-linear, elastic perfectly plastic finite element solutions strongly suggest that this might not be the case. Several suggestions as to the reasons for the deviation from continuum theory are presented.
Mechanical Property Characterisation of Crystalline, Ion Implantation Amorphised and Annealed Relaxed Silicon with Spherical Indenters
Authors: Williams J.S. , Field J.S. , Swain M.V. 
Published: March 2011

ABSTRACTSilicon single crystals have been ion implanted with Si ions at various energies and doses sufficient to achieve amorphisation to a depth of more than 1μm. This surface was subsequently annealed at 450°C for 30 minutes in vacuum to relax the implanted amorphous silicon. Mechanical properties of the different materials (crystalline, amorphous and annealed) were measured using a nominally 10 μm radius diamond tipped indenter and two indenting procedures; continuous loading and load partial-unloading. The crystalline material exhibited similar force-displacement behaviour to that observed by Weppelmann et al. [1] including a critical pressure to induce deformation on loading and a "pop-out" event during unloading. The amorphous and annealed materials showed a greater degree of plastic deformation but did not exhibit "pop-out" behaviour at lower loads (200 mN). The results are analysed to determine the difference of mean pressure with depth of penetration for all the materials. The onset of ductility was 5.5 to 6 GPa for the amorphous material and 10.9 GPa for the crystalline material. The depth dependence of hardness for the amorphous and annealed material showed substantial evidence of work hardening whereas the crystalline material did not.
Mechanical and Optical Properties of The Films of Tantalum Oxide Deposited by Ion-Assisted Deposition
Authors: Martin PJ. , Bendavid A. , Swain M.V. , Netterfield R.P. , Kinder T.J. , Sainty W.G. , Drage D. 
Published: March 2011

ABSTRACTThin films of tantalum oxide 1 μm thick were deposited by oxygen ion-assisted electron-beam evaporation onto silicon and glass substrates. The packing density and optical properties of the films were controlled by the degree of ion assistance during growth. The films were characterized for hardness by ultra-micro indentation measurement and density by RBS. A strong correlation of hardness, and optical properties was found with the ion-to-vapor arrival ratio at the substrate during deposition. Evaporated films without ion assistance were found to be relatively soft with hardness values of 5.3 GPa and 6.5 GPa on glass and silicon respectively when measured with a Berkovich indenter. When the ion bombardment was increased the film hardness increased to a maximum hardness of 10 GPa for 1000 eV O2 ion bombardment. The measured microhardness of the films was found to be influenced by the nature of the substrate for all depositions with higher microhardness values being recorded for films deposited onto silicon. The films were found to be amorphous and homogeneous. Additional ultra-microhardness measurements with a spherical tipped indenter enabled the depth dependence of hardness and modulus to be determined.
Stress of Tio2 Thin Films Produced by Different Deposition Techniques
Authors: Ottermann C. , Otto J. , Jeschkowski U. , Anderson O. , Heming M. , Bange K. 
Published: March 2011

ABSTRACTStress in thin films has been measured very precisely (< 10 MPa) by analysing the curvature of quartz glass substrates before and after film deposition by means of a ZYGO Mark IV interferometer system. TiO2 films of approximately 100 nm thickness were prepared by reactive evaporation (RE), reactive ion plating (IP), plasma impulse chemical vapor deposition (PICVD) and spin coating (SC). Large variations in stress are found for different coating techniques and deposition conditions. This can be correlated to differences in optical properties, film density and crystalline structure. Relaxation effects and the influence of thermal treatment are also studied. The crystallization of amorphous TiO2 during heat treatment is accompanied by significant changes in film stress. The crystal size and morphology of TiO2 films after heat treatment strongly depend on the deposition technique and process conditions.
Internal Strains and Relaxations in Lamellar TiAl
Authors: Hazzledine P.M. , Kad B.K. , Mendiratta M.G. 
Published: March 2011

ABSTRACTIn the lamellar form of the ordered intermetallic TiAl, mismatches at the lamellar interfaces, of order 1%, give rise to internal stresses and lo interracial dislocations. The geometry of the microstructure ensures extreme plastic anisotropy. Three main trends are evident in the plastic tensile properties: Both the yield and fracture stresses are low when deformation occurs in the plane of the lamellae and they are high when deformation occurs across the lamellae, the ductility is high when the tensile axis lies close to the lamellar plane and low when the tensile axis is nearly normal to the lamellar plane. The variations of the yield stress and the fracture stress are explained principally by the effects of Schmid factors and anisotropies in the Hall-Petch (or Stroh) stresses resulting from the lamellar shapes. The variation in ductility may be understood in terms of a competition between the ductile propagation of dislocations across interfaces and the creation of Stroh cracks at the heads of dislocation pile-ups.
Formation and Transformation of Amorphous Silicide Alloys
Authors: Tu K.N. , Tien T. , Herd S.R. 
Published: March 2011

ABSTRACTAmorphous silicide films can be formed by rapid quenching using techniques of vapor deposition and ion beam mixing and also by slow heating using solid state interdiffusion and reaction. For example, amorphous TaSi2 films can be formed by sputtering or dual electron guns co-deposition. Amorphous Pt2Si3 films have been produced by mixing PtSi and Si at room temperature with an ion beam at about 100 to 300keV. Recently, an amorphous Rh-Si alloy phase has been made by slowly heating to 300°C a very thin crystalline Rh films (∼50Å) on amorphous Si. The formation and crystallization behavior of these amorphous silicide alloys has been studied by transmission electron microscopy and electrical conductivity measurement.
Microdiffraction Studies of Small Gold Metallic Particles
Authors: Jose-Yacaman Miguel , Gomez Alfredo , Truszkowska Krystyna 
Published: March 2011

ABSTRACTThe crystalline structure of small gold particles in the size range between 50–200 Å is studied using STEM in microdiffraction.It is found that some single-crystalline particles showed an anomalous diffraction pattern. In some cases these pattern be indexed as an hexagonal lattice with a ratio c/a= 2.46. A number of models to explain the hexagonal diffraction are discussed. In some other cases the patterns correspond to fcc structures but with a large splitting effect. The results reveal the strong dynamical character of the diffraction by small gold particles.
The Structure of Grain Boundaries and Phase Boundaries in Ceramics
Authors: Carter C. B. 
Published: March 2011

ABSTRACTThe structure of different grain boundaries and phase boundaries are discussed by reference to a series of specific examples. The chosen examples of grain boundaries include the <l10>{l10} tilt boundary, the (001) twist boundary and the first-order twin boundary in spinel and the basal twin and the (1123) twin in Al2O3. The phase boundaries discussed are the β'''-alumina/spinel interface, the wustite/spinel interface and the spinel/alumina interface. It is shown that these interfaces do have properties which result specifically from the ionic nature of the material and the large unit cells involved in each case.
Tem of Dislocations in Sapphire (α−Al2O3)
Authors: Lagerlöf K.P.D. , Mitchell T.E. , Heuer A.H. 
Published: March 2011

ABSTRACTDissociation of both basal and prism plane dislocations in sapphire,α−Al2O3,is common and the partial dislocations can be imaged using conventional transmission electron microscopy and weak beam dark field imaging techniques. At elevated temperatures the dissociation takes place by conservative self-climb, a process involving short range diffusion, whereas at low temperatures the dissociation can occur by glide. Dissociation of a dislocation can in some situations give rise to very strong contrast when using g vectors for which g→.b→=0 for the undissociated dislocation. Those contrast conditions can be used to obtain information about the dislocation morphology and the stacking fault energy of the fault plane through determination of the separation distance.
High Resolution Tem Studies of β-Alumina Type Structures
Authors: Morrissey K. J. , Elgat Z. , Kouh Y. , Carter C. B. 
Published: March 2011

ABSTRACTHigh resolution transmission electron microscopy (HRTEM) has been used to study structures found in secondphase particles in commercial alumina compacts. Analytical electron microscopy has been used to identify elements present in the particles. Computer image simulation has been used for both the structural interpretation of high resolution images and predicting the effect which the presence of other elements would have on the observed structures.
Ordered Defect-Fluorite Compounds in ZrO2 Alloys
Authors: Farmer S. , Hangas J. , Lanteri V. , Mitchell T.E. , Heuer A.H. 
Published: March 2011

ABSTRACTIntermediate ordered-defect fluorite compounds are an important component of ZrO2 alloys containing the aliovalent solutes MgO, CaO, or Y2O3. These compounds also form in oxygen-deficient rare earth oxides and in other ternary oxides based on the fluorite structure, and can best be studied by TEM. Examples are given of such phases in the MgO-ZrO2, Y2O3-ZrO2, and CaO-ZrO2 systems.
Energy Release Due to Domain Formation in the Strained Epitaxy of Multivariant Films
Authors: Pompe W. , Gong X. , Suo Z. , Speck J.S. 
Published: March 2011

AbstractTwin related domain formation is examined as a strain relaxation mechanism for a heteroepitaxial tetragonal film on a cubic substrate. Elastic relaxations are calculated for a single twin band in which the c-axis of the tetragonal domains is either related by a 90* rotation about an axis in the plane of the film or by a 90* rotation about the surface normal. In all cases, the strain energy change is evaluated for both the film and the substrate. A domain pattern map is developed that predicts single domain and multiple domain fields depending on the relative misfit strains and domain wall energy. The concept of a critical thickness, hc, for domain formation is developed. For cases in which the c-axis is rotated 90* about an axis in the plane of the film, the critical thickness depends only on the relative coherency strain between the substrate and film and the ratio of the domain wall energy to the stored elastic energy. For the case of a pattern consisting of energetically equivalent domains with the c-axis in plane, the equilibrium distance of multiple domains is derived. For such multiple domains, a minimum wall separation distance exists which depends non-linearly on the film thickness.
Physicochemical and Microstructural Characterization of Rf Sputtering Magnetron Pb(ZrTi)O3 Thin Films
Authors: Varniere F. , Caytan E. , Eakim B. , Achard H. , Agius B. 
Published: March 2011

AbstractLead zirconate titanate thin films were deposited on Pt/TiN/BPSG/Si structures by sputtering an oxide target of nominal composition (Pb(Zr0.55,Ti0.45)O3 or PZT) in argon plasma. The PZT films were deposited at different pressures and different substrate temperatures ranging from floating temperature to 400°; the thicknesses of the sputtered films were in the 15-720 nm range. The absolute and relative cation and oxygen compositions of the thin films were determined by a new method based on the simultaneous use of Rutherford Backscattering Spectroscopy (RBS) and Nuclear Reaction Analysis (NRA) induced by a deuteron beam. The total deposition rate and atomic ones are observed as a function of the substrate temperature and pressure. Therefore the dependence of fil composition on pressure and substrate temperature is discussed.Post-deposition annealing studies and ferroelectric properties are presented. The values of the remanent polarization, Pr, were in the range 5-7 µC/cm2, the coercitive field, Ec, between 15 and 25 kV/cm and the dielectric constant, µr, evaluated from capacitance measurements around 1200, depending on the process parameters.
Imaging of Ferroelectric Domains in KTiOPO4 Single Crystals by Synchrotron X-RAY Topography
Authors: Wang S. , Dudley M. , Cheng L.K. , Bierlein J.D. , Bindloss W. 
Published: March 2011

AbstractThe application of synchrotron white beam X-ray topography to the study of ferroelectric domain structures in hydrothermally grown potassium titanyl phosphate (KTiOPO4: KTP) single crystals is reported. The domain walls can be exclusively imaged on topographs with selected diffraction vectors and X-ray wavelengths, while images of other defects, such as dislocations, inclusions and surface scratches, can be simultaneously made very diffuse. The topographic images correspond well with electrostatic toning images. X-ray topography readily reveals the three dimensional shapes of the domain walls. There are two contributions to domain wall contrast: one is fringe-like which can be interpreted in terms of the dynamical theory of X-ray diffraction, and the other is diffuse strain contrast arising from long range strain associated with the wall. These two contributions can be observed simultaneously or separately depending on the diffraction conditions. The long range strain is thought to be associated with the curvature of the domain walls. It appears that the main components of the displacement field associated with this strain are directed approximately perpendicular to the domain wall.
Study of Pbtio2 Formation Kinetics by an In-Situ Stress Measurement Technique
Authors: Li Chen C. , Desu Seshu B. 
Published: March 2011

AbstractThe primary objective of this study is to demonstrate an in–situ stress measurement technique for the study of formation kinetics of multicomponent thin films such as PbTiO3. Film stress–temperature and film stress–time plots have been successfully used to monitor the phase formation of PbTiO3 films in a in–situ way. It is believed that the mechanism of this reaction was dominated by grain boundary diffusion of the participating cations. The activation energy of the PbTiO3 phase formation from PbO/TiO2 double layers was estimated to be 108 kcal/mole.
Sputtering of Lead-Based Ferroelectrics
Authors: Iijima K. , Nagao N. , Takeuchi T. , Ueda I. , Tomita Y. , Takayama R. 
Published: March 2011

AbstractPbTiO3(PT), Pb1-xLaxTi1-x/4O3(PLT) and PbZrxTi1-xO3(PZT) thin films were prepared by rf magnetron sputtering. It was found that the thin films have remarkably large pyroelectric effect and high figures of merit for infrared sensors without poling treatment. High performance pyroelectric infrared sensors (single element and linear array) were fabricated by using the PLT(x=0.1) thin films with the new structures and the device process. This type of sensor is carried on the air conditioner to detect a thermal environment. The PZT thin films with x=0.9 showed a large remanent polarization of 46μC/cm2 and small coercive force of 28kV/cm. In addition, good endurance behavior (no degradation of Pr after 1011 cycles) was observed. Recent activities of ferroelectric thin film research in Japan is also reported.