bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of Adhesion Strength of Interfaces Between Thin Films Using Molecular Dynamics Technique
Authors: Iwasaki T. , Miura H. 
Published: April 2011

AbstractWe have developed a molecular-dynamics technique for determining the adhesion strength of the interfaces between different materials. In this technique the extended Tersoff-type potential is applied to calculate the adhesive fracture energy defined as the difference between the total potential energy of the material-connected state and that of the material-separated state. The adhesion strength of metal/dielectric interfaces as well as metal/metal interfaces is discussed based on this fracture energy. We used this technique to determine the adhesion strength of the interfaces between ULSI-interconnect materials (Al and Cu) and diffusionbarrier materials (TiN and W). The calculated adhesive fracture energy shows that the adhesion strength increases in the order: Cu/TiN, Cu/W, Al/W, and Al/TiN. Because this result was confirmed by scratch testing on the film-laminated structure, this technique is considered to be effective for determining the adhesion strength.
Adsorption/Desorption Phenomena in Silicate Glasses: Modeling and Application to a Sub-Micron Bicmos Technology
Authors: Hoffmann T. , Senez V. , Leduc P. 
Published: April 2011

AbstractIn this study, we present a numerical model, implemented in our two-dimensional Finite-Element process simulator, allowing the evaluation of the mechanical stress generated by deposited oxides in case of adsorbing or desorbing of water. Using both in-situ and ex-situ measurements of stress, the model parameters (water diffusion, evaporation rate, viscosity) are calibrated. Moisture instability of doped silicate glasses, like borophosphosilicate (BPSG) and phosphosilicate (PSG), is investigated. Moreover, an extension of the present model to simulate the densification of Spin-On-Glass (SOG) will be demonstrated. A failure analysis of a specific structure in an industrial process will validate the capability of the model to evaluate and minimize the risk of cracking in SOG films during densification.
Stress Effects on Al and Al(Cu) Thin Film Grain-Boundary Diffusion
Authors: Liu X.-Y. , Liu C.-L. 
Published: April 2011

AbstractStress effects on grain-boundary diffusion in Al and Al(Cu) thin films are evaluated through atomistic simulations. Specifically, the grain-boundary vacancy formation and migration and interstitial migration energetics are obtained as a function of stress states in thin film. In general, the activation energies vary at a rate of 0.1 eV per 1.0 % strain at the grain boundary investigated, indicating the possible impact on electromigration phenomenon in these films.
Measurement of Residual Stresses by Load and Depth Sensing Spherical Indentation
Authors: Taljat B. , Pharr G. M. 
Published: April 2011

AbstractThe finite element method was used to determine whether load and depth sensing indentation with spherical indenters may be useful in the measurement of residual stresses in materials. The spherical indentation process for a wide range of elastic/ideal-plastic materials to which compressive and tensile biaxial stresses were applied was simulated using standard finite element techniques. The elastic moduli and yield stresses of the materials were varied systematically to model the behavior of a wide variety of metals and ceramics. Elastic-ideal-plastic materials were considered in the study with residual stress levels varied from zero up to the yield stress. All three indentation regimes - elastic, elastic-plastic, and plastic - were examined, with emphasis given to the elastic and the early part of the elastic-plastic regimes, where differences in the load-displacement characteristics caused by residual stress were found to have a significant effect. Systematic examination of the relationships among residual stress, contact pressure, and elastic recovery revealed a simple, measurable indentation parameter which correlates well with the residual stress. Using this parameter, an experimental technique is proposed by which residual stresses can be estimated from measurements of the load of an indentation in the elastic-plastic regime, the yield stress, and the elastic modulus of the material, all of which can be determined by load and depth sensing indentation methods. Based on a critical examination of the technique by finite element simulation, the technique appears promising.
Mechanical Characterization of Surfaces by Nanotribological Measurements of Sliding and Abrasive Terms
Authors: Enders S. , Grau P. , Berg G. 
Published: April 2011

AbstractTo investigate the fumdamentals of the behavior of the friction of surfaces, nanotribological experiments have been performed on coated systems with thin glass films (SiO2-structure) and bulk fused silica, increasing the load on a Berkovich indenter oriented in edge or face-forward direction, respectively. The results depend strongly on the normal load and the contact area. For interpreting these results a new method of data analysis is presented, which explains the load dependence of the friction coefficient comprehensively. Particular attention is also focused on the effect of adhesion forces between the moving pairs. The good agreement between theory and experiment and the reasonable values of the material parameters obtained by fitting prove the validity of the presented analytical model.
Activation Volume for Inelastic Deformation in Polycrystalline Ag Films at Low Temperatures
Authors: Kobrinsky Mauro J. , Thompson Carl V. 
Published: April 2011

AbstractThe low temperature (T < 100 °C) inelasticity of polycrystalline Ag thin films on thick substrates has been studied. In-situ Transmission Electron Microscopy and stress-relaxation experiments indicate that thermally-activated glide of dislocations through forest-dislocation obstacles is the dominant inelastic mechanism. Values of the activation volume for inelastic deformation obtained with both experiments are reported. The mean distance between obstacles along the length of moving dislocations was found to be significantly smaller than the thickness of the film and the average grain size, which explains why current models for dislocationmediated plasticity underestimate the strength of thin films. Results from these experiments on Ag are expected to be representative of other metallic thin films (e.g. Cu and Au) on substrates.
The Microstructure, Phase and Ferroelectric Properties of PZT Thin Films on Oriented Multilayer Electrodes
Authors: Li Tingkai , Hsu Sheng Teng , Gao Yufei , Engelhard Mark 
Published: April 2011

AbstractThree kinds of oriented electrodes of Pt, Ir and Pt/Ir electrodes were prepared using electron beam evaporation techniques for deposition of PZT thin films. An oxide MOCVD reactor with liquid delivery system was used for the growth of PZT thin films. [Pb(thd)2], Zr(TMHD)4 and Ti(IPO)4 were dissolved in a mixed solvent of tetrahydrofuran or butyl ether, isopropanol and tetraglyme to form a precursor source. The deposition temperature and pressure were 500 - 650°C and 5 - 10 Torr, respectively. The experimental results showed PZT thin film deposited on various electrodes had different phase formation, microstructure and ferroelectric property. The X-ray patterns showed the perovskite phase of PZT was formed on both Ir and Pt/Ir electrodes at 550°C. The grain size of the PZT thin film increases after a further, higher temperature annealing. The as-deposited PZT thin film on Pt electrode exhibits pyrochlore phase at 550°C. The phase is transformed to perovskite phase after 650°C annealing. The experimental results also indicated that the MOCVD PZT thin film on Pt/Ir exhibits better ferroelectric and electrical properties compared to those deposited on Pt and Ir electrodes. A 300 nm thick PZT thin film on Pt/Ir electrode has a square, well saturated, and symmetrical hysteresis loop with 2Pr value of 40 μC/cm2 and 2Ec of 73 kV/cm at an applied voltage of 5 V. The hysteresis loop of the PZT thin film is almost saturated at 2 V. The leakage current of the film is 6.16 × 10−7 A/cm2 at 100 KV/cm. The electrode effects on ferroelectric properties of PZT thin films also have been investigated.
Effect of La Dopant on Electrical Properties of Pb(Zr,Ti)O3 Thin Film Capacitors
Authors: Kim Chang Jung , Chung Ilsub 
Published: April 2011

AbstractLanthanum doped lead zirconate titanate (PZT) thin films have been prepared on Pt/IrO2/Ir/SiO2/Si substrates to improve the ferroelectric and retention properties. The microstructure and electrical properties of the PZT capacitors were evaluated as a function of La content. The crystalline orientation was appreciably influenced by the addition of La in PZT thin films. The microstructures of films containing 0 and 0.5 mol% La were single phase perovskite, but for La = 1 mol%, a second phase was detected by SEM observation. The 0.5 mol% La doped PZT thin film capacitor showed the best ferroelectric and retention properties for ferroelectric random access memory compared to non-doped PZT.
Characterization of Ferroelectric BaTiO3 (100) Surfaces by Variable Temperature Scanning Surface Potential Microscopy and Piezoresponse Imaging
Authors: Kalinin Sergei V. , Bonnell Dawn A. 
Published: April 2011

AbstractVariable temperature atomic force microscopy (AFM), scanning surface potential microscopy (SSPM) and piezoresponse imaging were applied to the characterization of a model BaTiO3(100) surface. The influence of the domain structure on surface topography, surface potential and piezoresponse image is discussed. The domain induced surface corrugations and piezoelectric response were found to disappear above the Curie temperature in full agreement with theoretical expectations. Relaxation of apparent surface potential after the transition to paraelectric state on heating and during the transition to ferroelectric state on cooling was observed. The kinetics of potential relaxation was orders of magnitude slower than that of the transition.
Domain Images and Retention Properties of Pb(Zr,Ti)O3 Thin Films Observed by Electrostatic Force Microscopy
Authors: Jo William , Kim D. C. , Hong J. W. 
Published: April 2011

AbstractWe report results on domain retention in preferentially oriented Pb(Zr,Ti)O3 (PZT) thin films on Pt and on LaNiO3 (LNO) electrodes. Effects of bottom electrodes on domain images and retention properties have been explored by detecting an electrostatic force exerted on the biased conductive probe. It was demonstrated that polarization loss of PZT crystallites on LNO appears to be less than that of PZT grains on Pt. Moreover, charge retention was controlled by a reverse-poling protocol during electrostatic force microscopy (EFM) measurements. The surface charge density of the PZT films was observed as a function of time in a selected area where a region is single-poled and another region is reverse-poled. The retention behavior of the regions is very different; the single-poled region shows a declined response and the reverse-poled region reveals a retained characteristic. Decay and retention mechanisms are explained by space-charge redistribution and trapping of defects in the films.
Microstructure and Electrical Properties of PZT Thin Film Heterostructures on Silicon by pulsed laser deposition
Authors: Chattopadhyay Soma , Sharma A. K. , Kvit Alex , Jin Chunming , Lee C. B. , Collis W. J. , Narayan J. 
Published: April 2011

AbstractWe have been successful in the fabrication of (001) oriented epitaxial PZT films on YBCO/SrTiO3/MgO/TiN/Si heterostructures by pulsed laser deposition. The films were observed to be single phase by X-ray diffraction. The deposition parameters were varied to obtain the best epitaxial layer for each of the compounds. Transmission electron microscopy was employed for understanding of the structure, crystallinity and interfaces for each of these epilayers. Dielectric and P-E hysteresis loop measurements were carried out with evaporated Ag electrodes. The dielectric constant for the films was found to be around 380–400. The value of saturation polarization Ps was between 40–50 μC/cm2 and the coercive field Ec varied from 45–55 kV/cm. Integration of PZT films with silicon will be useful for future memory and micromechanical devices.
Structure - Property Relationships of Thin Films of Epitaxial Ferroelectric Bismuth-Layered Perovskites with Even and Odd Aurivillius' Parameters
Authors: Pignolet A. , Harnagea C. , James A. R. , Senz S. , Zakharov N. D. , Hesse D. 
Published: April 2011

AbstractThin films of bismuth-layered perovskites with the generic formula (Bi2O2)2+(An- 1BnO3n+1)2- with an even Aurivillius' parameter n like SrBi2Ta2O9 (n = 2) and BaBi4Ti4O15 (n= 4) and with an odd Aurivillius' parameter like Bi4Ti3O12 (n= 3) and Ba2Bi4Ti5O18 (n=5) have been grown by pulsed laser deposition on epitaxial conducting LaNiO3 electrodes on single crystalline (100) SrTiO3 or on top of epitaxial buffer layers on (100) silicon. The films are shown to grow epitaxially, however, they do not have a single crystallographic orientation but several preferred orientations. The films consist of both c-axis-oriented regions and mixed (110)-, (100)- and (001)-oriented regions. The regions with mixed orientation feature rectangular as well as equiaxed crystalline grains embedded in a c-oriented matrix, protruding out of its smooth surface. Macroscopic as well as microscopic measurements of the ferroelectric properties of regions with pure c-orientation and of regions with mixed orientations showed a clear relationship between their ferroelectric properties and their morphology and crystallographic orientation. In the regions with mixed orientation, the films exhibited saturated ferroelectric hysteresis loops with well-defined remanent polarization Pr and coercive field Ec. The regions having c-axis orientation with a smooth surface morphology, in contrast, exhibited a linear P-E curve with no hysteretic behavior for SrBi2Ta2O9 and BaBi4Ti4O15, and weak ferroelectric behavior for Bi4Ti3O12. These results might have a technological impact due to the relevance of bismuth-layered ferroelectric oxides for the fabrication of non-volatile FeRAM memories.
MFMOS Capacitor with Pb5Ge3O11 Thin Film for One Transistor Ferroelectric Memory Applications
Authors: Li T. K. , Hsu S. T. , Lee J. J. , Gao Y. F. , Engelhard M. 
Published: April 2011

AbstractA ferroelectric Pb5Ge3O11 thin film with a low dielectric constant is proposed for application in one transistor ferroelectric memories. A strong depolarization voltage on the ferroelectric capacitor with MIFSFET structures diminishes the remanent polarization significantly and, therefore, the low dielectric constant becomes very important to widen the memory window. A memory window of 3V was estimated for the MFMOS memory structure with 2000Å ferroelectric Pb5Ge3O11 and a 100Å gate oxide. In the second part of this paper, Pb5Ge3O11 films deposited on Ir/Ti/SiO2/Si substrates, by using MOCVD system, was demonstrated. Germanium ethoxide, Ge(OC2H5)4, and lead bis-tetramethylheptadione, Pb(thd)2, were used as the MOCVD precursors. The film composition, phase formation, microstructure and ferroelectric properties are reported. The c-axis oriented Pb5Ge3O11 thin films prepared by MOCVD and RTP post-annealing showed a square ferroelectric hysteresis loop with Pr of 2.83 μC/cm2 and EC of 49 kV/cm. A low leakage current of 7.5 × 10−7 A/cm2 at 100 kV/cm and low dielectric constant of 41 were also demonstrated.
Relaxor Pb(Mgl/3Nb2/3)O3 Thin Films: Processing, Dielectric and Electrostrictive Properties
Authors: Kighelman Z. , Damjanovic D. , Seifert A. , Gentil S. , Hiboux S. , Setter N. 
Published: April 2011

AbstractLead magnesium niobate, Pb(Mg1/3Nb2/3)O3, thin films were formed from alkoxide-based solution precursors. To obtain stable and reproducible PMN precursor solution, a special effort has been undertaken to optimize the precursor synthesis. The organic decomposition behavior and crystalline phase development in a dried gel powder are reported. The influence of different seeding layers on the microstructures is shown. Dielectric and electromechanical measurements were carried out. Films show relaxor-like behavior, but with dielectric permittivity which is low (4500 at peak) compared to bulk ceramics and single crystals. Several parameters which might be responsible for this lower permittivity are suggested. Large electric dc bias fields (up to 120 kV/cm) can be applied to the films. This dc field reduces the permittivity, suppresses the frequency dispersion and flattens the permittivity peak. The anomaly associated with the field induced transition into a ferroelectric phase was not observed. Electrostrictive strains versus amplitude of electric field were measured and are discussed.
Study of the Transverse Piezoelectric Coefficient of Pb(Zr,Ti)O3 Thin Films as a Function of Texture and Composition
Authors: Seifert A. , Ledermann N. , Hiboux S. , Muralt P. 
Published: April 2011

AbstractThe effective transverse piezoelectric coefficient was measured on 1 μm thick sol-gel processed Pb(Zr,Ti)O3 (PZT) thin films as a function of texture and composition. Optimal values were obtained with PZT films of {100} texture near the morphotropic phase boundary (53/47). The best value amounted to -12 C/m2
Excimer Laser Liftoff of Epitaxial Pb(Zr,Ti)O3 Thin Films and Heterostructures
Authors: Tsakalakos L. , Sands T. 
Published: April 2011

AbstractEpitaxial (100) and (111)-oriented Pb(Zr,Ti)O3-based thin films and heterostructures have been transferred intact from their sapphire and MgO growth substrates to silicon and polymer substrates utilizing a novel laser liftoff process. The heterostructures, while on their growth substrate, were bonded to the receptor substrates using one of several bonding methods, including van der Waals bonding to an elastomer receptor, and transient liquid-phase Pd-In bonding to Si. A single 38 ns pulse from a KrF excimer laser (<,= 248 nm) directed through the transparent growth substrate induced localized heating of the perovskite interfacial layer. At fluences corresponding to the onset of vaporization (>300 mJ/cm2), the sapphire or MgO substrate was detached. Because of the short pulse length and the low thermal conductivity of Pb-based perovskite phases, heating of the top surface of the heterostructure was minimal, thus permitting film transfer to thermally-sensitive receptor substrates. X-ray rocking curves revealed slight broadening of the principal PLZT diffraction peaks (∼10–20%), suggesting local relaxation of film stress.
Tem Investigation of Growth Temperature Dependence in Pulsed-Laser Ablated PLZT Films for Pyroelectric Applications
Authors: Jacobs R. N. , Godfrey R. P. , Sarney W. L. , Tipton C. W. , Salamanca-Riba L. 
Published: April 2011

AbstractTransmission electron microscopy is used to examine the structural characteristics of Pb0.9La0.1Zr0.2Ti0.8O3 (PLZT) films grown directly on single crystal LaAlO3 (LAO) substrates. In particular, the domain orientation and film epitaxial quality as a function of substrate deposition temperature are obtained in the range 500–650°C and compared to x-ray diffraction results. High-resolution cross sectional images and electron diffraction patterns confirm that domain orientation and overall epitaxial quality can be optimized with growth temperature. In addition, these results show a direct correlation with pyroelectric measurements obtained for capacitor structures incorporating La1−xSrxCoO3 (LSCO) top and bottom electrodes.
Thermal Stability of Ir/TaN Electrode/Barrier on Thin Gate Oxide for MFMOS one Transistor Memory Application
Authors: Zhang Fengyan , Hsu Sheng Teng , Li Tingkai , Ono Yoshi , Maa Jer-shen , Ying Hong , Stecker Lisa 
Published: April 2011

AbstractThe Metal-Ferroelectric-Metal-Oxide-Silicon (MFMOS) one transistor memory requires a metal electrode directly on top of the thin gate oxide. The gate oxide used in our present MFMOS one transistor memory processing is 30 Å SiO2. Ir has been chosen for the bottom electrode and TaN was used as the barrier layer between the Ir and thin gate oxide. It has been shown from previous studies that a TaN barrier layer can effectively prevent the formation of iridium silicide and can enhance the adhesion between Ir and Si or SiO2 substrates. But it is more important that the TaN itself is stable and will not react with the gate oxide during ferroelectric material deposition, annealing and subsequent processing. In this paper, TaN barriers with different deposition conditions have been deposited on 30 Å gate oxide. 1500 Å Ir was deposited on the TaN barrier layer. Capacitors of Ir/TaN/gate SiO2/Si were defined by dry etching. Series RTP annealing were performed in oxygen from 500 to 650 °C with annealing times from 5 min to 90 min. The capacitor was also annealed in a nitrogen ambient at 1000°C for 10s. C-V and I-V studies were used to characterize the stability of the Ir/TaN/Gate SiO2 structure. It was observed that the Ir/TaN/Gate SiO2 is very stable during the above mentioned annealing conditions. The consumption and further oxidation of the gate oxide is negligible and would depend on the deposition condition of the TaN barrier layer. With optimized deposition conditions, a 220 Å TaN barrier layer can effectively prevent any iridium silicide formation and will not degrade the gate oxide during annealing processing. The interfaces between the TaN and gate SiO2 and between the gate SiO2 and Si substrate can be further improved by forming gas annealing.
Preparation of SrRuO3 and CaRuO3 Films by Mocvd and its Application to Electrodes for Ferroelectric Thin Films
Authors: Okuda N , Higashi N , Ishikawa K , Nukaga N , Funakubo H 
Published: April 2011

AbstractSrRuO3 and CaRuO3 thin films were successfully prepared by metalorganic chemical vapor deposition (MOCVD). Sr(C11H19O2)2(C8H23N5)x – Ru(C11H19O2)3–O2 and Sr(C11H19O2)2(C8H23N5)x. – Ru[(C5H4)(C2H5)]2 - O2 systems, and Ca(C11H19O2)2(C8H23N5)x, – Ru(C11H19O2)3–O2 and Ca(C11 H19O2)2(C8H23N5)x – Ru[(C5H4)(C2H5)]2– O2 systems were used as source materials for SrRuO3 and CaRuO3 thin film preparation, respectively. Sr and Ca source vapors were successfully obtained by bubbling N2 gas including C8H23N5 vapor through liquid sources. Self-composition limiting to keep single phase of SrRuO3 and CaRuO3 was observed under an excess input of the Ru source at 700 – 750 °C for both Ru sources. Epitaxlly grown films with high crystal perfection were grown on various kinds of substrates in this temperature range. Epitaxially grown SrRuO3 film with three kinds of orientation, (100), (110) and (111), were deposited on (100), (110) and (111)SrTiO3 substrates, respectively. By using these films as bottom electrodes, we measured the ferroelectric anisotropy of SrBi2Ta2O9 by preparing (001)- and (116)- oriented films.
Autostoichiometric Mocvd Of Multicomponent Thin Films LiTaO3, LiNbO3 and SrxBa1-xNbO6
Authors: Zhang R. , Xu R. 
Published: April 2011

AbstractA novel stoichiometric vapor deposition process, Autostoichiometric MOCVD, was developed in this study to prepare stoichiometric thin films. Heterometallic alkoxides were used as single precursor for two different metal components in Autostoichiometric MOCVD. The molecular ratios of the metals were conserved through the precursor evaporation and the deposition reactions based on the chemical nature of precursors and the deposition reaction mechanisms. A non-stoichiometric factor K was defined to study the evaporation process of precursors. A precursor evaluation method using the K factor and the thermal decomposition analysis was introduced to quantitatively analyze the stoichiometric evaporation characteristic of a heterometallic alkoxide precursor. Single phase LiTaO3, LiNbO3, SrNb2O6 and BaNb2O6 films were successfully obtained using precursor LiTa(n-OBut)6 or LiTa(i-OBut)6, LiNb(n-OBut)6, SrNb2(n-OBut)12 and BaNb2(n-OBut)12, respectively. Solid solution Sr1-x.BaxNb2O6(SBN) films were also successfully obtained by a two-step Autostoichiometric MOCVD.