bluuebunny/crossref_metadata_2025_split huggingface dataset:
Piezoresponse in Ferroelectric PZT Thin Films
Authors: Kiselev Dmitry , Bdikin Igor , Movchikova Alena , Kholkin Andrei , Suchaneck Gunnar , Gerlach Gerald 
Published: April 2011

ABSTRACTPoled ferroelectric lead zirconate titanate (PZT) films comprising a (111) texture on (100)Si/SiO2/(111)Pt substrates were investigated by piezoresponse force microscopy (PFM). Depending on the film thickness, the crystallite orientation varies from purely (111) (related to the Pt bottom electrode orientation) to a more random texture. By PFM, 90° domains with a width of 50 nm were obtained in an individual grain Pb(Pb0.10Zr0.21Ti0.69)O3 − PPZT (10/21/69). It was shown that the virgin (unpoled) films possess large piezoelectric activity comparable to that after local poling (self-polarization effect). This corresponds to a clear predominance of the domains with a polarization oriented from the bottom electrode to the free surface of the film.
Investigation of Epitaxially Grown PbO, TiO2 and ZrO2 as Bridge Layers for Integration of PZT on GaN by MBE
Authors: Gu Xing , Izyumskaya Natalia , Avrutin Vataliy , Morkoç Hadis 
Published: April 2011

ABSTRACTEpitaxial growth of PbO, TiO2 and ZrO2 has been achieved on MOCVD grown GaN template using oxides MBE with a reactive H2O2 oxygen source. In situ RHEED was used to monitor the growth in-situ. AFM was used to characterize the surface morphology of the thin PbO and ZrO2, which show streaky, 2-D RHEED patterns. XRD pattern indicates that the growth orientation of these oxides are PbO [111]//GaN [0002], ZrO2[100]//GaN [0002] and TiO2[200]//GaN[0002].
Characterization of Ferroelectric Properties of Bi4-xPrxTi3O12 Polycrystals
Authors: Munro Abril , Mata Jorge , Martínez Eduardo , Siqueiros Jesus 
Published: April 2011

ABSTRACTEffects of Praseodymium doping on the ferroelectric properties of Bi4Ti3O12 were investigated using dense ceramics from room temperature to 730 °C. DRX and XPS studies shows that the structure can accept only 10% of praseodymium without the precipitation of second phases. Thermoelectric analysis and ferroelectric hysteresis measurements were performed and show that the incorporation of praseodymium modified the transition temperature Tc and slightly the polarization values. The incorporation of praseodymium resulted in a variation in the permittivity and in the remanent polarization (2Pr). The polarization characteristics in the samples doping were different to Bi4Ti3O12.
Effect of CuO on Microstructure and Microwave Dielectric Properties of CaTiO3-Ca(Zn1/3Nb2/3)O3 Ceramics System
Authors: Yu Hongtao , Hao Hua , Liu Hanxing , Tian Zhongqing 
Published: April 2011

ABSTRACTThe effect of CuO on the microstructure and microwave dielectric properties of the CaTiO3-Ca(Zn1/3Nb2/3)O3 ceramics prepared by the conventional solid-method has been investigated. Doped with the 0.5∼1.25wt% CuO powder, the system of which the sintering temperatures were lowered exhibited the orthorhombic perovskite. It can effectively promote the microwave dielectric properties of the 0.3CaTiO3-0.7Ca(Zn1/3Nb2/3)O3 system at lower sintering temperature at the level of 1.0wt% CuO additive. The quality factor increases from 10860 to 13900GHz and not any significant change was observed in the TCF value with fixed CuO additive at different sintering temperature.
Dielectric Permittivity Mapping up to 9GHz Region with Non-contact Microwave Probe for Ferroelectric Device
Authors: Kakemoto Hirofumi , Li Jianyong , Harigai Takakiyo , Nam Song-Min , Wada Satoshi , Tsurumi Takaaki 
Published: April 2011

ABSTRACTDirect observations for high frequency microscopic dielectric distributions in cross sections of a multi-layer ceramic capacitor were carried out using non-contact type microwave probe. The measured data were imaged from the raw data and rounding data process. Using microwave reflection intensity mappings from cross sections of multi-layer ceramic capacitor, the dielectric permittivity distribution in micro-region of a multi-layer ceramic capacitor was measured at room temperature. The spatial resolution was experimentally estimated to be about 10 μm from mappings of the dielectric and inner electrode layers in a multi-layer ceramic capacitor.
Dielectric Tunability Properties and Thermal Stability of (Ba,Sr,Ca)TiO3 Thin Films Prepared by the Sol-Gel Method
Authors: Qin Wei , Chen Wanhai , Wu Wenbiao , Cheng Jinrong , Meng Zhongyan 
Published: April 2011

ABSTRACTA new family of (Ba1-x-ySrxCay)TiO3 (BSCT) thin films was prepared on Pt(111)/TiO2/SiO2/Si substrates by using sol-gel techniques. BSCT thin films with Ba/Sr/Ca ratio of 15/55/30, 20/45/35 and 25/35/40 were investigated, which were selected at the cubic region in the vicinity of the cubic-tetragonal phase boundary according to the ternary phase diagram of BaTiO3-SrTiO3-CaTiO3. X-ray diffraction analysis indicates that BSCT thin films are of the cubic perovskite structure. No hysteresis window can be observed from the capacitance-voltage curves, reflecting that BSCT thin films are in the paraelectric phase. The dielectric constant and tunability of BSCT thin films were investigated in the temperature range of 200–370 K. The Curie temperature Tc increases with increasing Ba concentration.
Electrical Study of Device Arrays on Thin Film Vanadium Dioxide
Authors: Mani Ramesh G. , Ramanathan S. , Narayanamurti V. 
Published: April 2011

ABSTRACTThe VO2 phase of vanadium oxide is known to exhibit large changes in the electrical and optical properties in the vicinity of the structural phase transition at 68C. Here, we report on the fabrication and study of thin film vanadium oxide (VO2) devices deposited on R-plane sapphire. Thin films prepared by electron beam evaporation have been processed by photolithography into two-terminal strips for electrical measurements. Measurements on such specimens exhibit reproducibility across a chip, in addition to hysteretic transport, and a one-to-two orders of magnitude change in the resistance in the vicinity of the structural transition. In sum, these experiments show that e-beam evaporation of VO2 constitutes a simple and useful approach to realizing devices from this technologically important material.
Reactive Multilayer Foils for Silicon Wafer Bonding
Authors: Qiu Xiaotun , Wang Jiaping 
Published: April 2011

ABSTRACTIn this study silicon wafers were bonded using Al/Ni reactive multilayer foils as local heat sources for melting solder layers. Exothermic reactions in Al/Ni reactive multilayer foils were investigated by XRD and DSC. XRD measurements showed that dominant product after exothermic reaction was ordered B2 AlNi compound. The heat of reaction was calculated to be -57.9 KJ/mol by DSC. With Al/Ni reactive multilayer foil, localized heating can be achieved during bonding process. Both experimental measurements and numerical simulation showed that the heat exposure to the wafers was highly limited and localized. Moreover, leakage test showed that this bonding approach possessed a good hermeticity.
Compression Creep Behavior of the 95.5Sn-(4.3, 3.9, 3.8)Ag-(0.2, 0.6, 0.7)Cu Solders
Authors: Vianco Paul , Rejent Jerome , Kilgo Alice , Martin Joseph 
Published: April 2011

ABSTRACTThe compression creep properties were evaluated for the Pb-free solders 95.5Sn-4.3Ag-0.2Cu (wt.%), 95.5Sn-3.9Ag-0.6Cu, and 95.5Sn-3.8Ag-0.7Cu to determine the effects of small composition differences on time-dependent deformation. The test temperatures were -25°C, 25°C, 75°C, 125°C, and 160°C. The nominal applied stresses were in the range of 2 – 45 MPa. Samples were tested in the as-fabricated condition as well as post-aged at 125°C for 24 hours. Negative creep was recorded for all three alloy compositions. However, the extent of this phenomenon was sensitive to alloy composition and the aging treatment. Creep deformation resulted in the formation of coarsened-particle boundaries within the eutectic regions of the microstructure. The boundaries were comprised of Cu6Sn5and, to a lesser extent, Ag3Sn particles. The minimum creep rate kinetics were evaluated for these solders. The sinh term exponent, n, was 4 – 6 for the Sn-Ag-0.2Cu and Sn-Ag-0.6Cu solders and 1 – 2 for the Sn-Ag-0.7Cu alloy. The apparent activation energy (ΔH) values were in the range of 30 – 70 kJ/mol for all alloys, indicating that a short-circuit or fast-diffusion mechanism controlled creep deformation. The aging treatment did not consistently alter the rate kinetics parameters amongst the alloys. Separating the minimum creep rate data into the low and high temperature regimes, [-25°C, 75°C] and [75°C, 160°C], respectively, showed that bulk diffusion contributed to creep in the higher temperature regime. The ΔH values for the low temperature regime, which indicated that creep was dominated by a fast-diffusion mechanism, were sensitive to solder composition.
Electric Current Induced Brittle Failure of Eutectic Lead and Lead-free Solder Joints with Electroless Ni-P Metallization
Authors: Kumar Aditya , Chen Zhong , Wong C. C. , Mhaisalkar S. G. , Kripesh Vaidhyanathan 
Published: April 2011

ABSTRACTThe mechanical properties of thermally-aged and electric current-stressed eutectic lead (Sn-37Pb) and lead-free (Sn-3.5Ag) solder joints with electroless Ni-P metallization were investigated using tensile testing. Multi-layered test samples, electroless Ni-P/solder/electroless Ni-P, having two electroless Ni-P/solder interfaces were prepared. Tensile testing results showed that for both types of solder, high density electric current causes the brittle failure of solder joint. The eutectic lead solder joint was found to be more prone to current induced brittle failure compared to the lead-free solder joint. In the eutectic lead solder joint, brittle failure always occurred at the cathode side electroless Ni-P/Sn-37Pb interface (where electrons flowed from Ni-P to solder), whereas no such polarity effect was observed in the case of lead-free solder joint.
Parylene-PDMS Bilayer Coatings for Microelectronic and MEMS Packaging
Authors: Lee Hyungsuk , Cho Junghyun 
Published: April 2011

ABSTRACTCurrent microelectronic devices and microelectromechanical systems (MEMS) require that packaging costs be reduced with more enhanced device performance. In addition, the packaging materials are often exposed to harsh environments, for which their performance is drastically degraded. Importantly, such devices become lighter and smaller, precluding the use of conventional packaging materials and schemes. Given that, surface coatings can provide an alternative solution for some of the aforementioned issues. Polydimethylsiloxane (PDMS) is a good candidate material in many encapsulating applications but its surface must be effectively protected due to its poor surface properties. In this study, the PDMS surface is coated with the parylene C film through a vapor-phase deposition. Proper surface modification of PDMS is then essential to generate desirable interfacial adhesion and performance between the parylene C and the PDMS. Effects of plasma treatment were examined in this study to evaluate their effectiveness on the surface modification of the PDMS. In order to explore mechanical performances of the bilayer coatings, dynamic nanoindentation and feedback-control nanoindentation testings were employed. In addition, extensive surface characterizations are performed with atomic force microscope (AFM) and optical microscope (OM).
Through Wafer Interconnects - A Technology not only for Medical Applications
Authors: Vogtmeier Gereon , Drabe Christian , Dorscheid Ralf , Steadman Roger , Wolter Dr. Alexander 
Published: April 2011

AbstractThe foremost driver for the development of fully CMOS compatible Through Wafer Interconnects (TWIs) is the need of very large photodiode arrays for detectors, e.g. in computed tomography applications. The front to back-side contact allows the four-side buttable chip placement of the already large chips (20mm × 22mm2). The TWI technology allows an interconnection for chips up to 280μm thickness. This technique does not require any via opening at the font side, thus enabling a metal signal routing on the active side, on top of the interconnection. The application specific optical sensitive front-side of the chip is fully accessible. The production process is separated into three main steps. The first step is the implementation of the special TWI geometry into the CMOS substrate. Depending on the electrical and geometrical requirements of the circuit, different TWI structures are built with deep trenches (up to 280μm), which are passivated and filled with doped poly-silicon. The technologies used in this process, such as DRIE-etching, oxidation and low pressure CVD, are standard CMOS compatible processes. The use of poly-silicon prevents from achieving very low resistivity interconnections but allows the use of all CMOS process steps for an imager production (no temperature limitation – compared to other TWI process flows). The second step is the standard CMOS processing on the substrate already including the TWIs. The third step is a low temperature back-side process starting with wafer thinning down to 280μm or less to open the implemented TWI structure from the back-side. The thickness may be selected depending on the target application. A modified under ball metallization (UBM) process, which could include also re-routing of signals on the back-side, concludes the process flow until the solder ball placement, or similar bond connections.The special process flow opens a variety of applications which benefit from the full CMOS compatible processing and the accessible front-side.
γ-Irradiation Stimulated Change of Recycled Polypropylene Composites Dielectric Permittivity
Authors: Gafurov Ulmas , Fazilova Z. 
Published: April 2011

AbstractThe γ-irradiation influence on dielectric permittivity (ε′) of recycled polypropylenes (PPR) and of thermoplastic composites γV TDV on its bases has been investigated. It was investigated follows thermoplastic composites: PPR+EPDM, PPR+EPDM+GTR, PPR+EPDM+GTR/plast; EPDM -ethylene-propylene diamine. The permittivity increasing up to dose ∼ 100 kGy one can explained of radiation stimulated peroxide radicals formation, processes of cross-linking and increase of ordering, crystallinity degree. It is supported the measurements of the IR spectra of irradiated samples and by the data of X-ray diffraction measurements.The dielectric permittivity for the PPR+EPDM and PPR+EPDM+GTR/plast composites have little change up to the dose of γ-irradiated 1500 kGy and the composites have stable dielectric properties. The stable properties is defined the radiation stable of polymer (PPR) matrix. The dose raise more lead to the permittivity decreasing for the plasticized composite PPR+EPDM+GTR/plast. It is result of crystallinity degree reduction and by plasticization of destruction products.
Fabrication of SiN-assisted 0.12um AlGaAs/InGaAs PHEMT and 60GHz-band MMICs for 60GHz WPAN system
Authors: Ahn Hokyun , Lim Jong-Won , Ji Hong-Gu , Chang Woo-Jin , Mun Jae-Kyoung , Kim Haecheon 
Published: April 2011

AbstractIn this paper, the fabrication technology of SiN-assisted 0.12um double deck T-gate AlGaAs/InGaAs p-HEMT and 60GHz-bands MMICs for the high rate personal area network (WPAN) system was described. The effect of the gate shape such as the 1st-deck and the 2nd-deck gate head size on the DC and RF characteristics of the p-HEMT device and the device performance at the optimum gate head size were also presented. At 0.22um of the optimum 1st-deck gate head size and 1um of the 2nd-deck head size, the p-HEMT device with two finger gates of 0.12um length × 50um width shows an extrinsic transconductance of 529mS/mm and a threshold voltage of -1.19V. The cut-off frequency and the maximum frequency of oscillation were 94.7GHz and 189.1GHz, respectively. The gate shape of the p-HEMT device such as a gate head size is correlated to parasitic capacitances including Cgs which have effects on RF performances including a cut-off frequency (fT) and a maximum frequency of oscillation (fmax).
3-D Integration Latest Developments at LETI
Authors: Charlet Barbara 
Published: April 2011

ABSTRACTWe review the latest 3-D integration developments performed in LETI, giving some devices integration examples and discussing the achieved performances. Direct bonding and layer transfer (smart cut™) is now largely used to process innovative substrates like: SOI, SSOI, GeOI, … and others. This type of new substrate can play a crucial role in 3D structure integration and can answer the requirements for new challenging performances.3-D integration approach has been used and will be presented in the following topics: advanced packaging by neo-wafers, chip to wafers integration, hetero-structures integration and wafer to wafer concept (front and back-end application). The examples of neo-wafer rebuilding for advanced packaging, the hetero- structure achieved by chip-to-wafer or wafer-to-wafer bonding and front-end and back-end architecture are discussed regarding the 3-D integration challenging requirements. The challenging cases of wafer-level integrated demonstrators for high density 3D inter-chips connections and wireless interconnections are presented. For some examples we give also the first electrical performances achieved with representative demonstrators.
Fabrication and Evaluation of 3D Packages with Through Hole Via
Authors: Jang Dong Min , Lee Kwang Yong , Ryu Chung Hyun , Cho Byeong Hoon , Oh Tae Sung , Kim Joung Ho , Lee Won Jong , Yu Jin 
Published: April 2011

ABSTRACTSystem in package (SiP) is a superb candidate to enhance the area efficiency and performance of electronic packaging. Here, recent work on stacked chip type 3D SiP with vertically interconnected through hole vias are reported. The process includes; formation of 50um-diameter via holes, conformal deposition of SiO2 dielectric layer, deposition of Ta and Cu barrier layers, via filling by Cu electroplating, Cu/Sn bump formation for multi-chip stacking, and finally chip-to-PCB bonding using Sn-3.0Ag-0.5Cu solder and ENIG pad. A prototype 3D SiP stacked up to 10 layers was successfully fabricated.A high frequency electrical model of the through hole via was proposed and the model parameters were extracted from measured S-parameters. The proposed model was verified by TDR/TDT (time domain reflectometry/time domain transmission) and eye-diagram measurement. Contact resistances of Cu via and bump joint were presented.
Hydrogen Desorption from MgH2 Based Nano-Micro Composites
Authors: Bonetti Ennio , Fiorini Anna Lisa , Pasquini Luca , Abazovic Nadica , Montone Amelia , Vittori Antisari Marco 
Published: April 2011

ABSTRACTThe microstructure and hydrogen sorption behaviour of MgH2 based nano-hydrides with different additives prepared by ball milling and inert gas condensation has been investigated by XRD, Differential Scanning Calorimetry and Mechanical Spectroscopy. Preliminary results on materials with similar composition and different nanostructures show that suitable mechanical processing and additive additions induce in the nanostructured composites tailored channels for improved ab/de-sorption kinetics at reduced temperatures.
Supported High Temperature Protonic Films Produced by Solid State Reaction
Authors: Meulenberg Wilhelm A , Serra José M. 
Published: April 2011

AbstractThis work presents the last progresses in the development of thin oxidic proton conducting electrolytes supported on mixed conducting cermets making use of a solid state reaction. The procedure includes preparation routes applying solid state transformation of an already-gastight oxide layer (typically doped zirconia and ceria) by reacting with an alkali-earths layer (stoichiometric amount) deposited by screen printing on top of that. This kind of supported films can find application as IT-SOFC, H2-membranes and advanced catalytic converters. Thin-film (∼5μm) proton conducting membranes with the nominal composition as for instance BaZr0.85Y0.15O3-δ and BaCe0.8Gd0.2O3-δ were prepared over porous Ni-8YSZ or Ni-CGO substrates by solid state reaction. The produced films are gastight with a homogeneous composition, and showed a highly crystalline cubic perovskite structure. The solid state reaction promoted the formation of (i) a different grain size distribution from 0.1 μm for barium zirconate to 2-3μm for barium cerate, and (b) the formation of a porous fibrous top-layer (for barium zirconate) or a just flat surface (for strontium zirconate), depending on the exact composition of the reacting oxides.
Ionic Conduction in Nanoscale Films of Yttrium-Doped Barium Zirconate
Authors: Shim Joon Hyung , Gur Turgut M , Prinz Fritz B 
Published: April 2011

AbstractProton conductivity of yttrium-doped barium zirconate grown on MgO(100) using pulsed laser deposition (PLD) has been explored as a function of film thickness (60∼670nm) related to crystal and grain structure in the nano scale. Highly textured thin film (60nm) without significant grain separation showed high ionic conductivity close to the bulk BYZ value while thick polycrystalline samples showed lower values with clear grain and grain boundary formation.
Refractory Cathode Investigation for Single-Step Co-Fired Solid Oxide Fuel Cells (SOFCs)
Authors: Zink Peter A. , Yoon Kyung Joong , Huang Wenhua , Gopalan Srikanth , Pal Uday B. , Seccombe Donald A. 
Published: April 2011

AbstractA single step co-firing process for fabricating solid oxide fuel cells (SOFCs) requires refractory electrodes to prevent excessive sintering of the electrode while facilitating full-density sintering of the electrolyte. Single cell current-potential curves and impedance measurements indicate that the majority of the performance losses occur in the cathode and are due to activation polarization. A-site deficient calcium and cerium doped lanthanum ferrite cathode powders were synthesized and investigated as possible refractory cathode materials with low activation polarization losses. Four-probe conductivity measurements indicated that all compositions were suitable as cathodes. However, reactivity with YSZ reduced the conductivity by as much as two orders of magnitude, too low for use as a cathode. These refractory cathode compositions could be effective if a suitable barrier layer is applied to prevent reaction with YSZ. Experiments will investigate the applicability of a doped-ceria barrier layer to prevent reaction between the lanthanum ferrite cathode layer and the YSZ electrolyte layer.
LixCn as Anode Material for Lithium Ion Batteries
Authors: Xie Haiming , Yu Haiying , F. Jalbout Abraham , Yang Guiling , Pan Xiumei , Wang Rong-Shun 
Published: April 2011

AbstractWe design a way that the anode hosts provide lithium ion in lithium ion battery operation. If the limiting factors of the cathode materials are less, there will be more alternatives for it. It was proven to be successful by two kinds of test cells based on LixCn as anode material, and β-FeOOH or Cr8O21 as cathode materials. Their theoretical capacities are much higher than those present electrode materials. Unlike the lithium secondary batteries with lithium metal foil or lithium alloy as anode, this type of lithium ion batteries with LixCn as anode prohibit dendrite formation during charging-discharge process. The idea of lithium ion sources coming from the anode can come true successfully as a result that steady protecting solution be sought for LixCn.