Yong Soo Cho Yonsei University
Harrie A. C. Tilmans IMEC
Takaaki Tsurumi Tokyo Institute of Technology
Gary K. Fedder Carnegie Mellon University
J1: Packages & LTCC
Tuesday PM, March 25, 2008
Room 2009 (Moscone West)
9:30 AM - **J1.1
Design, Fabrication, And Characterization Of Embedded Resistor Heaters For Die Attach On A Multilayer Low Temperature Cofired Ceramic Package.
Kevin Ewsuk 1 , F. Uribe 1 , F. Dempsey 1 , L. Rohwer 1 Show Abstract
1 , Sandia National Laboratories, Albuquerque, New Mexico, United States
Resistors embedded in low temperature cofired ceramic (LTCC) multilayer packages have the potential to serve as localized heaters to reliably attach die (i.e., microchips) to the surface of a complex multilayer microelectronics package. The feasibility of this concept has been demonstrated with specially designed and fabricated multilayer LTCC test coupons containing embedded heaters that were formed using thick film materials, and through thermo-mechanical model simulations completed using Sandia’s Calagio finite element (FE) code. This paper will describe the test coupon design and fabrication, and the results of the thermal testing and simulations that have been completed. Additionally, results from modeling and experiment will be compared and contrasted. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000
10:00 AM - **J1.2
New Technologies in LTCC Process for Highly Integrated Module
Jong-Hee Kim 1 Show Abstract
1 , korea Institute of Ceramic Engineering & Technology, Seoul Korea (the Republic of)
In the system development field for the network construction of ubiquitous society, the transition to high frequency, the high-speed RF communication technology and the miniaturization of multifunctional device would be key technologies of the most important requirements in that field. It is LTCC (Low Temperature Cofiring Ceramics) technology that materializes those three key technologies, which can make several components, such as circuits, decoupling capacitor, filter, balun, etc., into single integrated module, and building up 3-dimensional structure. In the case of higher density integration where electric circuit needs finer wiring, the precise alignment between layers became difficult due to high shrinkage in LTCC module during co-firing process. To solve the problem fundamentally, constrained sintering has been studied and adopted practically in a few LTCC field. With the increasing need of passive components embedding, the embedding technology of decoupling capacitor also has been studied so much and it can be known that high permittivity material should be embedded for capacitor into the low permittivity layer of multilayer module. In this study, a novel sintering process is proposed for both the self-constrained sintering and the bonding of BaTiO3 and Al2O3 layers. The process is explained by the mechanism where filler and glass layers are fabricated separately and then glass material infiltrates into filler layer. The feasibility of new constraining mechanism was proved in the self-constrained sintering and the bonding of different LTCC materials. Finally, micro-patterning effort in fine line/spacing and via-holes onto the constrained layers using photo-imageable thick film pastes will be presented.
10:30 AM - **J1.3
RF SOP (System On Package) Using Passive Embedded Substrate.
Nam Kang 1 Show Abstract
1 Electronic Materials & Packaging Research Center, Korea Electronics Technology Institute, Gyeonggi-do Korea (the Republic of)
The convergence paradigm of today, which can be characterized as multi-function and high-effectiveness, requires integrating RF analogue function and high speeding digital function into a single IC or package. System on package (SOP) is a technology integrating system into a package to meet these requirements of today. Passive embedded substrate is a key technology in achieving the small sized devices as a module with high integration density especially in wireless communication area.This presentation will describe integration approach for passive embedded substrate for RF integrated package. With the several examples such as multi-band front end module and passive/active integrated module, the merits of the integration using passive embedded substrates unlike using surface mount technology (SMT) and design considerations in embedded passive substrates will be presented.
11:45 AM - J1.6
Very High Frequency Silicon Nanowire Nanoelectromechanical Systems Toward Large Scale Integration.
Philip X.L. Feng 1 , Rongrui He 2 , Peidong Yang 2 , Michael Roukes 1 Show Abstract
1 Kavli Nanoscience Institute, California Institute of Technology, Pasadena, California, United States, 2 Chemistry, University of California, Berkeley, Berkeley, California, United States
Nanoelectromechanical systems (NEMS), especially those operating in their vibrating resonance modes (a.k.a, NEMS resonators), have emerged as novel devices and new tools that are attractive for a wide spectrum of important applications such as ultrasensitive resonant-mode detections of mass, force, and charge, nanomechanical logic, and radio-frequency (RF) signal processing. Such NEMS resonators and their performance strongly rely on the constituting materials and device processing and integration. While NEMS devices made by top-down surface nanomachining with materials such as silicon carbide (SiC) can offer ultrahigh operating frequencies, suspended single-crystal nanowires represent a natural choice for NEMS resonators with well-defined surface and crystalline orientations established in the bottom-up chemical synthesis.We have demonstrated NEMS resonators with fundamental mode frequencies >200MHz, well in the upper range of the very high frequency (VHF) band, by employing single-crystal bottom-up SiNWs. Based on the recent discovery of the giant piezoresistive effect in very thin SiNWs, we have also developed VHF SiNW NEMS resonators utilizing such piezoeresistive effect in resonance detection. In this work, we systematically explore the electromechanical characteristics of SiNW NEMS resonators, with a focus on resonance transduction schemes (including both excitation and detection) that are promising for large scale integration of SiNW NEMS. Not only for the bottom-up SiNWs, but also for the top-down devices patterned from silicon-on-insulator (SOI) wafers, with typical device width in the 50−150 nm range and length of 2−10um, we demonstrate HF and VHF SiNW resonators based on magnetomotive, piezoresistive, and electrostatic (capacitive) transductions and their combinations. We evaluate the efficiencies of the transduction schemes in measurements, as well as in analyses of their corresponding circuit models and scaling laws. While magnetomotive schemes (at both low- and room- temperatures) have attractive transduction efficiency and scalability with increasing device frequency, retaining such efficiency on chip is a great challenge. Piezoresistive and capacitive transductions are more attractive in terms of system integration. We demonstrate second-order piezoresistive frequency down-conversion, and enhanced capacitive with integrated LC matching networks, as efficient transduction schemes for VHF NEMS. Finally, we show our development of wafer-scale manufacturing of large arrays of SiNW NEMS.
12:00 PM - J1.7
Low-loss Dielectric Ceramic and Polymer Composites for Integrated Electronics.
Gullu Kiziltas 1 , Isil Berkun 1 , Zuhal Tasdemir 2 Show Abstract
1 Mechatronics, Sabanci University, Istanbul Turkey, 2 Material Science and Engineering, Sabanci University, Istanbul Turkey
Tuesday PM, March 25, 2008
Room 2009 (Moscone West)
2:30 PM - **J2.1
Multilayer Ultrathin Film PLZT Capacitor Fabrication and Integration Issues.
Bruce Tuttle 1 , Geoff Brennecka 1 , Chad Parish 1 , Luke Brewer 1 , Jill Wheeler 1 , John Ekerdt 2 Show Abstract
1 , Sandia National Laboratories, Albuquerque, New Mexico, United States, 2 , University of Texas at Austin, Austin, Texas, United States
Ultrathin (<50 nm) PLZT film multilayer capacitor structures with effective dielectric constant and polarization values equivalent to those of conventional thin films (> 200 nm) and bulk materials have recently been achieved in our laboratory. Advanced multilayer ultrathin film structures are needed to meet the enhanced areal capacitance requirements for medical electronics, miniaturized sensor devices and energy conversion components. Chemical solution deposition techniques were developed to fabricate ultrathin film multilayer capacitors with as many as 5 layers and capacitance densities greater than 0.5 µF per mm2. Detailed investigations of process parameters have optimized dielectric properties for PLZT ultrathin film layers with thickness as small as 20 nm. Specifically, single layer PLZT ultrathin films with high dielectric constants (>1000) and large maximum polarization values (> 40 μC/cm2) have been achieved in the present study. A present focus of our work is the fabrication and materials integration issues for these novel high areal capacitance density multilayer structures. Analyses of the electrode/dielectric interface(s) at the nanoscale were used to evaluate low temperature interactions of ultrathin film PLZT with underlying Pt and Ir electrode technologies. Initially, it was found that Pb interactions with Pt electrodes limited the ultimate thickness for which ultrathin film PLZT dielectric layers had excellent dielectric and ferroelectric properties. We combined intelligent materials processing modifications with high resolution materials analysis techniques to gain the technical insight to transform fluorite / pyrochlore phases to the desired perovskite phase. The nanostructural and microstructural features obtained are shown to be reproducible and are dependent on the sequence of process steps. Development of the scientific understanding of the phase transformation process was critical in retaining high dielectric constant behavior for multilayer ultrathin films at the nanoscale. We have demonstrated that capacitance values of appropriately processed multilayer ultrathin film capacitors increased linearly with the number of layers. Further, effective maximum polarization values in excess of 35 µC/cm2 were obtained for 3 layer devices with 120 nm thick individual dielectric layers. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000.
3:00 PM - **J2.2
Integrated (Ba,Sr)TiO3 Thin Film Technology for RF and Microwave Applications
Toshimasa Suzuki 1 , Daiki Ishii 1 , Kentaro Morito 1 , Youichi Mizuno 1 Show Abstract
1 Materials R&D div., Taiyo Yuden Co., Ltd., Takasaki, Gunma Japan
BaxSr1-xTiO3 (BST) thin-film ferroelectrics are being extensively studied for application in voltage-controlled tunable RF and milliwave devices in next-generation broadband wireless communication systems as well as in more commonly known capacitor applications such as DRAM storage capacitors and integrated decoupling capacitors. Although some devices have already been commercialized in a limited market, dielectric thin-film technology is in its initial stages of development and numerous problems have to be solved for further improving electrical performance and reliability. Parallel-plate tunable capacitors are suitable for recent customer-end applications that have stringent voltage requirements due to their lower control voltage operation that is compatible with well-established silicon logic devices. Further, parallel-plate capacitors that have lower parasitics coupled with a substrate enable integration into low-cost silicon platforms that are suitable for high-volume production and future monolithic integration of RF-MEMS devices.This presentation will present the overview of our parallel-plate BaSrTiO3 and SrTiO3 thin-film capacitor technology on a silicon platform for RF and milliwave devices. The columnar grains constituting dielectric thin films were epitaxially grown on (111) oriented Pt grains, forming a well-structured incommensurate interface without lattice-misfit strain. The in-plane thermal stress was controlled by the ion bombardment effect depending on sputtering deposition pressure. The stress-controlled films exhibited a high resistance to thermal stress and high permittivity stemming from the reduction of in-plane tensile stress while involving a high density of lattice strain. The high-frequency dielectric analysis combined with the equivalent circuit model and electromagnetic simulation demonstrates the intrinsic dielectric properties in the GHz band, which comprises the slight dispersion of dielectric constant and linear increase of the dielectric loss with frequency and well-defined electromechanical resonance due to the piezoelectric effect. The piezoelectric resonance can be controlled by optimizing thickness; however, the high extrinsic dielectric loss, possibly due to crystal imperfection, remains a serious issue, which might be difficult to resolve for the thin films involving a high density of meta-stable defects such as dislocations, planar defects, and point defects.
3:30 PM - **J2.3
Size Effect And Dead Layer Of Bst Thin Films.
Takaaki Tsurumi 1 , Takashi Matsuo 1 , Takuya Hoshina 1 , Hirofumi Kakemoto 1 Show Abstract
1 Dept. of Metallurgy and Ceramic Science, Tokyo Institute of Technology, Tokyo Japan
It is known that the dielectric permittivity of BaxSr1-xTiO3 (BST) thin films decreases with film thickness. Two mechanisms have been proposed to explain this phenomenon: the one is the 'size effect' where the permittivity somehow decreases with film thickness and the other is the formation of the 'dead layer' with low permittivity at the film/electrode interfaces. However, we still cannot answer the simple questions: Does the size effect truly exist in the BST films? What is the meaning of dead layer? This work has been done to answer these simple questions. The BST films with different thicknesses were deposited on SrRuO3/SrTiO3 substrate and top electrodes of Pt, Au, Ag and In were formed on the film surface. The complex admittance data were analyzed to separate the capacitance of the BST films and the depression layers formed at the film/electrode interfaces. The depression layer thickness was estimated for each electrode to calculate the permittivity of the films and depression layers from the Schottky barrier model. It was found that the permittivity of the BST films was independent of the electrodes but that of depression layers increased with the work function of metals. High internal fields were found to be applied to the depression layers according to the difference of work functions between the BST films and metal electrodes. It is concluded that no size effect exited in the epitaxial BST films and the dead layer is the depression layer of nonlinear dielectric with low permittivity under high internal bias fields.
4:30 PM - **J2.5
Preparation Of Pzt Thin Films With (001) Orientation And Their Piezoelectric Applications.
Eiji Fujii 1 , Ryoichi Takayama 2 , Koji Nomura 2 , Akiko Murata 2 , Taku Hirasawa 2 , Atsushi Tomozawa 2 , Satoru Fujii 2 , Takeshi Kamada 2 , Hideo Torii 2 Show Abstract
1 Advanced Technology Research Labs, Matsushita Electronic Components Co., Ltd., Osaka Japan, 2 Advanced Devices Development Center, Matsushita Electronic Components Co., Ltd., Osaka Japan
Preparation of Pb(Zr,Ti)O3 (PZT) thin films with (001) orientation and their piezoelectric applications to a sensor and an actuator were investigated. These thin films, which have a composition close to the morphotropic phase boundary (MPB), were epitaxially grown on (100)MgO single-crystal substrates by rf magnetron sputtering. These PZT thin films with (001) orientation could be obtained on various kinds of substrates, such as glass and Si, by introducing MgO buffer layers with (100) orientation. In addition, the PZT thin films with (100) orientation could be obtained on Si substrates without buffer layers by optimizing the sputtering conditions. All of these thin films showed excellent piezoelectric properties without poling treatment. The PZT thin films on the MgO substrates had a high piezoelectric coefficient d31 of –100 pm/V, and extremely low relative dielectric constant εr of 240. The PZT thin films on Si substrate had a very high d31 of –150 pm/V and εr = 700. The PZT thin films were applied to an angular rate sensor with a tuning fork for a car navigation system and for shake compensation of digital still camera. A higher performance and smaller volume of one-third than the conventional angular rate sensor with a quartz tuning fork have been realized, due to use of the PZT thin films which have excellent piezoelectric properties and a high-precision Si tuning fork fabricated by Si deep etching. The PZT thin films were also applied to the actuators of the inkjet heads for industrial on-demand printers. The inkjet head consists of actuators with the PZT thin films, pressure chambers, ink canals and nozzle plates with water-repellent thin films. Each inkjet head developed had 400 nozzles and 400 pressure chambers. On-demand printers feature higher printing speeds and greater printing widths than inkjet printers for consumer use. For this reason, a line head device with an arrangement of 30 inkjet heads in a row was developed. The line head device, which has a very high number of nozzles (12,000), was fixed to the on-demand printer and remains immobile during printing, so that high printing speed of 60 m/sec and increased printing width of 500 mm are realized. In addition, high printing resolution of 600 dpi was realized by slanting each inkjet head in the sending direction of the printed matter. The PZT thin films with (001) orientation are useful for sensors and actuators in MEMS.
5:00 PM - J2. 6
Lead Zirconate Titanate Thin Film Embedded Capacitors for Printed Circuit Board Applications.
Inhyung Lee 1 , Jung Won Lee 1 , Seung Eun Lee 1 , Yul Kyo Chung 1 , Byung Ik Song 1 , Bae Kyun Kim 1 Show Abstract
1 Central R&D Institute, Samsung Electro-Mechanics, Suwon Korea (the Republic of)
We demonstrate that it is possible to process lead zirconate titanate (Pb(Zr0.52Ti0.48)O3, or PZT) thin films on copper based copper clad laminate (CCL) substrates. PZT films, 700 nm in thickness, have been transferred from their sapphire substrates to CCL receptor substrates using laser liftoff process. Pulsed excimer laser irradiation of an absorbing thin film through a transparent substrate has been employed to separate epitaxial PZT thin film from their sapphire grown substrates. PZT thin films on CCL substrates exhibit superior dielectric characteristics, capacitance density of 2.0uF/cm2, and leakage current less than 1uA/cm2 at 10V via sol-gel technology and laser liftoff method. This demonstration has broad implications, opening up the possibility of the use of low-cost, high processing temperature and high-conductivity copper electrodes for a range of Pb-based perovskite materials, including PZT films in embedded printed circuit board applications for capacitors.
5:15 PM - J2.7
Tunable Thin Film Integrated Material Characterizations for Microwave Applications
Mahmoud Al Ahmad 1 , Robert Plana 1 Show Abstract
1 , LAAS CNRS, Toulouse France
Transferred J2.8 @ 4:30 m to J2.7 @ 4:15 pmTunable Thin Film Integrated Material Characterizations for Microwave Applications. Mahmoud Al Ahmad
Yong Soo Cho Yonsei University
Harrie A. C. Tilmans IMEC
Takaaki Tsurumi Tokyo Institute of Technology
Gary K. Fedder Carnegie Mellon University
J6: MEMS II
Thursday PM, March 27, 2008
Room 2009 (Moscone West)
2:30 PM - **J6.1
PZT Films Embedded Microcantilever Based Sensors for Biomolecule Detection.
Kyo Seon Hwang 1 , Sang Kyung Kim 1 , Ji Yoon Kang 1 , Tae Song Kim 2 Show Abstract
1 Nanobio Research Center, Korea Institute of Science and Technology, Seoul Korea (the Republic of), 2 Intelligent Microsystem Center, Korea Institute of Science and Technology, Seoul Korea (the Republic of)
Current disease diagnosis depends on fast and specific detection of marker biomolecules. The necessities of detection tools with advantages such as, accuracy, high sensitivity, reproducibility, and rapidness are directly related to the medical and biological markets. Here, we present actuating layer (PZT thin & thick films) embedded microcantilevers for detecting the marker proteins by measuring a mechanical proterty (i.e. resonant frequency) before and after the specific interaction of biomolecules. Our nanomechanical dynamic microcantilevers were proposed as a new sensing tool that allows early, rapid, and correct detection in clinical range. We fabricated microcantilever with composition of Ta/Pt/PZT/Pt/SiO2 layer on a SiNx supporting layer by standard MEMS fabrication process. PZT films was deposited using sol-gel method for thin films and screen printing method for thick films. New mathematical model was developed by consideration of multi-layered cantilever structure and the relation between surface stress and resonant frequency. Theoretical results from new mathematical model were correspondenced with experimental results that measure the resonant frequency of microfabricated cantilevers and mechanical property change of cantilever in biomolecular interaction. This indicated that the resonant frequency shift was dominated by the surface stress in biomolecular interaction. The surface stress generated by biomolecular interaction was calculated in range of mN/m level. The new model enabled more tangible understanding of the protein dynamics in bioassay. Moreover, we could detect and analyze several biomolecules (Postate specific antigen, Myoglobin antigen, C-reactive protein and HCV helicase) related to disease by using our fabricated microcantilever. Four different biomolecules (proteins) were quantitatively detected by the functionalized microcantilevers. The dynamic range of our microcantilevers was ranging from pg/ml level to ng/ml level. Limit of detection (LOD) was distributed from 10 pg/ml to 1 ng/ml depending on target, which was low enough for applications in clinical diagnosis.In addition, sensing performance of microcantilevers was enhanced by physical and biochemical methods. We used established washing condition, smaller microcantilever, and sandwich assay using polyclonal antibody with and without nanoparticles for selectivity and sensitivity improvement. The reproducibility was improved from 21.48% (coefficient of variance (CV)) to 15.68% and the sensitivity was enhanced to 1 pg/ml.The capacity of dynamic microcantilevers is the sensitive, accurate, rapid and label-free biomolecules detection and analysis. The self-exciting cantilever sensor which has a relatively 10-30 times larger quality factor as compared with thermally resonating cantilevers will lead to a rapid biochemical analysis tool as well as a disease diagnostic system.
3:00 PM - J6.2
Portable, Autonomous Battery-powered Piezoelectric MEMS-based Platform using Molecularly Imprinted Polymers for Biomedical Assays.
Cedric Ayela 1 , Fanny Vandevelde 2 , Karsten Haupt 2 , Liviu Nicu 1 , Laurent Tanguy 1 Show Abstract
1 Nanobiosystems Department, LAAS CNRS, Toulouse France, 2 , Compiègne University of Technology, Compiegne France
3:15 PM - J6.3
2-D Acoustic-Microfludic Particle Focusing Devices for Miniaturized Flow Cytometry
Surendra Ravula 1 , Michael Baker 1 , Darren Branch 1 , Karl Westlake 1 , Igal Brener 1 Show Abstract
1 Applied Photonic Microsystems, Sandia National Labs, Albuquerque, New Mexico, United States
Over the last 50 years, flow cytometry systems have become commonplace in clinical and research environments and the gold standard for diagnosis of a large number of diseases. In this presentation, we discuss our work towards building a sheathless acoustic-microfluidic flow cytometry device that uses standing acoustic waves to spatially confine particles as they flow. When fully integrated, these microfabricated platforms could be a low cost, portable alternative to conventional flow cytometry systems. A square cross section microchannel (214μm) and corresponding through wafer ports are created in silicon using a two mask deep reactive ion etching (DRIE) Bosch process. The channel dimensions (214μm width and height) are chosen such that they set up acoustic standing waves both laterally and vertically when actuated at 3.5MHz. A piezoelectric transducer is glued to the underside of the silicon substrate to couple acoustic energy into the channel. A glass coverslip (quarter-wavelength thickness) is anodically bonded to the top of the silicon microfluidic manifold to create an acoustic reflector and to allow optical access to the flowing particles within the channels. Previous work on similar devices has concentrated on one dimensional spatial positioning, and to our knowledge, this work represents the first attempts at spatially confining flowing beads and cells in both width and height using a single transducer and simultaneous excitation of half wavelength resonances. Moreover, previous work in two-dimensional particle focusing in microchannels has concentrated on the use of cylindrical capillaries which are rather incompatible with other “lab-on-a-chip” microfabrication processes.In this device, particles injected into the channel when the piezoelectric transducer is actuated will move to the center of the channel both along the height and width simultaneously. Alternately, beads can be shifted to the sides of these channels by exciting a resonance along the cavity width. This feature can be used to route particles to one of several outlets for back-end particle sorting applications. In this presentation, we will discuss initial results on the spatial confinement of fluorescent beads, and the metrics that are relevant for flow-cytometry applications. Finally, we will discuss other designs where laminar flow can be used in conjunction with acoustic levitation to achieve similar functionality.
4:15 PM - J6.5
Influence of Phase Distribution on the Magnetostrictive Behavior of Iron-Gallium Alloys.
Qingfeng Xing 1 , Dongmei Wu 1 , R. William McCallum 1 , Thomas Lograsso 1 Show Abstract
1 Materials and Engineering Physics Program, Ames Laboratory, Ames, Iowa, United States
Fe-Ga alloys exhibit an attractive combination of large magnetostriction and superior mechanical properties to other magnetostrictive materials. This makes them promising in sensor and energy-harvesting applications. The magnetostriction, (3/2) λ100, shows two maximums as a function of Ga concentration. The structure-property correlation still remains open even though extensive microstructural study has been carried out. This work focuses on the phase identification by transmission electron microscopy (TEM) for Fe-Ga single crystals with Ga composition before and after the first maximum and on the structure-property correlation.Fe-Ga single crystals were grown by Bridgman method. The as-grown crystals were annealed at 1000 °C for 168 hr and cooled at 10 °C/min. One millimeter thick samples were then annealed in Ar for 3 hrs and then quenched in ice-water. Sample composition was determined by an electron microprobe calibrated with standards. TEM samples were prepared by electro-jetting. A Tecnai F20XT TEM and a Philips CM30 TEM were used at a nominal operation voltage of 200 kV.TEM results demonstrate that the magnetostriction is structure dependent. The magnetostriction increases monotonically for compositions less than about 18 at% Ga for the slow-cooled samples and about 21 at% Ga for quenched samples which corresponds to single phase disordered bcc (A2) phase. The A2 single phase was identified by the lack of superlattice reflections in the electron diffraction patterns of  and  zone axes. A phase mixture, consisting of A2 and order-bcc phase D03, is linked to the drop in magnetostriction after the first maximum. This two-phase mixture was revealed by the presence of the superlattice reflections and the domain-like contrast of the dark-field images formed by (002) or (111) reflections of D03 phase. Under slow cooled conditions, a Fe-18.7at%Ga alloy shows a heterogeneous structure with D03 domains dispersed in A2 matrix. The size of the D03 domains varies from several nanometers to tens of nanometers. The domain boundaries are not sharp. The D03 domain size becomes larger with increasing Ga addition. For example, Fe-20.7at%Ga alloy exhibits a domain size up to 100 nm with clear contrast between A2/D03 boundaries. Quenching of these two alloys avoids the occurrence of D03 ordering, resulting in single phase A2. The present result of the phase-composition-property relations is in general agreement with previous X-ray diffraction and TEM data.Recently a similar property-phase relationship, where a monotonic increase of magnetostriction for A2 single phase and a decrease for mixtures of A2 and D03, has also been found in Fe-Ge single crystals. However, the D03 phase in Fe-Ge shows negative strain in contrast to positive strain for Fe-Ga D03 phase, suggesting that both the magnitude and sign of magnetostriction are strongly dependent on electron band structure in addition to local atomic arrangement.
4:30 PM - J6.6
Quantitative Evaluation and Patterning of Covalently Bound Molecular Nanostructures on GaP (100) Surfaces
Rosangelly Flores-Perez 1 , Dmitry Zemlyanov 2 , Albena Ivanisevic 3 1 Show Abstract
1 Department of Chemistry, Purdue University, West Lafayette, Indiana, United States, 2 Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana, United States, 3 Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, United States
The study utilizes surface sensitive techniques in order to quantitatively characterize the nature of organization and bonding of alkanethiol adsorbates on GaP (100) surfaces. The evaluation was performed using water contact angle, atomic force microscopy (AFM), Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The hydrophobicity and consistency of surface roughness were studied via water contact angle and AFM. The FT-IR experimental protocol permitted the identification of characteristic functional groups on the surface and enabled insight into the organization within the adlayers on the GaP surface. XPS data showed evidence for the formation of a covalent bond between the sulfur and the surface, and was used to calculate the adlayer thicknesses, tilt angles and molecular coverages for different adsorbates. The thickness and tilt angles values were comparable to other modified semiconductor materials. High coverages were observed for all alkanethiols on GaP (100). The quantitative XPS protocol reported can be applied to the evaluation of other adsorbates on semiconductor materials. Upon the validation of the alkenathiol surface modification, we used microcontact printing (μCP) and dip-pen nanolithography (DPN) to create patterns on GaP (100). The chemical and morphological properties of the patterns were characterized by surface sensitive techniques as well. The results of this work can be used to improve the passivation of micro-fabricated devices composed on GaP layers.
4:45 PM - J6.7
Vertical Carbon Nanotube Scaffolding as an Alternative to Deep Reactive Ion Etching, Applicable to a Wide Variety of Materials
David Hutchison 1 , Brendan Turner 1 , Robert Davis 1 , Richard Vanfleet 1 Show Abstract
1 Physics and Astronomy, Brigham Young University, Provo, Utah, United States
We present a novel method to make high aspect ratio structures in a variety of materials by growing patterned vertically-aligned carbon nanotubes (VACNTs) and then filling the space between tubes with various materials by chemical vapor deposition (CVD). It is possible to grow structures up to 1mm tall with vertical sidewalls, wall roughness of about 100 nm, and minimum feature size of a few microns. The nanotubes are grown from a lithographically patterned 2nm Fe catalyst film. This substrate is heated to 750 °C in a tube furnace flowing hydrogen and ethylene, causing multiwalled carbon nanotubes to grow together vertically upward from the surface from the patterned Fe film, at controllable rates of over 100 μm/min. Next, this structure can be easily filled in with amorphous carbon by heating to 950 °C in ethylene alone, or it can be filled by low-pressure CVD with other materials like Si, Si3N4, or metals. Even nanotubes deep inside the forest are found to be uniformly coated with the "filler" material. Since the CNTs serve only as scaffolding and constitute a small volume fraction of the structure, the final product mostly consists of this filler material. In many ways, this is a more flexible alternative to Deep Reactive Ion Etching since it is not Si-specific, and appears cheaper, faster, simpler, and more scalable. To demonstrate the usefulness and flexibility of this approach, we have made a variety of high aspect ratio structures including high-temperature TEM grids (allowing the sample they hold to be annealed) and a simple MEMS mechanism.
Yong Soo Cho Yonsei University
Harrie A. C. Tilmans IMEC
Takaaki Tsurumi Tokyo Institute of Technology
Gary K. Fedder Carnegie Mellon University
J8: New Materials & Processing
Friday AM, March 28, 2008
Room 2009 (Moscone West)
9:30 AM - **J8.1
Microcontact Printing of Thin Film Electroceramics.
Susan Trolier-McKinstry 1 , Hajime Nagata 1 , Song-Won Koh 1 , Clive Randall 1 , Pascal Pinceloup 2 , Mike Randall 2 Show Abstract
1 , Penn State, University Park, Pennsylvania, United States, 2 , Kemet Electronics Corporation, Fountain Inn, South Carolina, United States
There is an ongoing need to develop new technologies to enable further down-scaling of layer thicknesses in multilayer ceramic devices, with the most urgent of these being multilayer capacitors (MLC). There are about 1012 MLC prepared annually. Currently, they are made by tape casting powder slurries, screen-printing, and laminating. In order to prepare a thin film version of such a capacitor, it is essential to demonstrate films with high dielectric constants (>1000) over a wide temperature range, stacking of these films into a multilayer configuration, and an inexpensive means of assembling the films. This paper describes chemical solution deposited BaTiO3 films on Ni foils with permittivities >1500 down to film thicknesses <150 nm with good temperature stability. Micro-contact printing of chemical solutions of both the dielectric and electrode layers was explored as an economical means of preparing patterned thin film-based MLC without requiring photolithography. For this purpose, methanol/acetic acid-based BaTiO3 solutions were spun onto polydimethylsiloxane stamps, printed onto substrates, pyrolyzed, and crystallized. LaNiO3 and Cu were used as prototype electrodes that could also be microcontact printed. The line edge roughness produced this way was excellent, which should enable very small margins. The printed layer thickness was also very uniform. Multilayer stacking was also demonstrated. Consequently, microcontact printing appears to be an interesting alterative means of preparing MLC with layer thicknesses in the range of ≤0.2 μm. The same technology is also attractive for inexpensive patterning of lower layer count devices for integrated passive components.
10:00 AM - **J8.2
Micro/Nano-scale Direct-patterned Thin Film Formation by Photon/E-beam Induced Metal-organic Deposition.
Hyung-Ho Park 1 , Hyeong-Ho Park 1 , Hyuncheol Kim 1 Show Abstract
1 Ceramic Engineering, Yonsei University , Seoul Korea (the Republic of)
For the application of thin films to system devices, patterning process should be carried out. Ion etching and ion milling are presently the most widely applied processes for fine patterning of film. However, these processes are found to degrade the properties of film. So, new patterning technology of film, which does not induce the degradation of the properties of film, has been required. Direct patterning method such as photon or e-beam induced metal-organic deposition (PMOD or EMOD) is one of novel technique for film formation without using either photoresist or dry etching because of photon or e-beam sensitive nature of starting precursors. Especially in the case of PMOD, unlike sol-gel procedure which is based on chemical reaction including hydrolysis and condensation, metallic state is obtained through the removal of organic ligand by exposure to UV. And this metal usually turns to oxide through the oxidation reaction with atmospheric oxygen during the exposure to UV. PMOD and EMOD have been revealed to be suitable for the control of stoichiometry and furthermore lithographically producing micro- or nano-sized patterning without the requirement of separated etching procedure. In this presentation, PMOD for the micro-sized patterning and EMOD for the nano-sized patterning are discussed including the deposition mechanism, physico-chemical properties and electrical/optical properties of ferroelectric films and transparent conducting oxide films.
10:30 AM - J8.3
Novel Composite Materials for Frequency-Specific Microwave Absorption.
Nathan Fischer 1 , Nicola Bowler 1 Show Abstract
1 Materials Science and Engineering, Iowa State University, Ames, Iowa, United States
There are many instances where it is desirable to absorb specific frequencies of microwave radiation. Areas of interest include radar applications, enhancing the performance of cell phones, and in microwave-assisted curing of thermosets. The traditional solution to this problem is through the use of ferromagnetic powders dispersed in a matrix to form a composite. These powders exhibit a ferromagnetic resonance in the microwave frequency range, which is exploited for the production of microwave-absorbing composites. The resulting composites are typically heavy, due to the high mass density of ferromagnetic materials, and in many instances this is not desirable. An alternative option is to take advantage of dielectric relaxation due to interfacial polarization as the means of electromagnetic absorption. It has been shown  that this can be achieved in the microwave spectrum through the use of homogenous filler particles, with a conductivity near 10 S/m, dispersed in an inert matrix. An alternative method is to coat a dielectric sphere with a thin conductive layer to produce the desired dielectric relaxation. This approach has the advantage of the providing the ability to adjust the relaxation frequency by altering the ratio between the radius of the sphere and the thickness of the conducting layer .In previous work , the dielectric properties of composites formed with tungsten-coated, hollow glass spheres dispersed in wax has been measured. The spheres had mean diameters of 30μm but a broad size distribution (15 and 55μm the 10th and 90th centiles, respectively). The sputter-coated tungsten layer was discontinuous and had a nominal thickness of 20nm. These composites exhibited a very broad relaxation feature, whose breadth was ascribed primarily to the discontinuous nature of the tungsten layer giving rise to variation in the effective conductivity, and the wide dispersion in the diameters of the glass spheres.In order to more finely control the dielectric relaxation, a different method of coating metal onto dielectric spheres has been investigated. It was theorized that tighter control of the metal deposition process would lead to better control of the strength of the relaxation peak and the frequency where the relaxation takes place. New glass spheres with tighter size distribution (±5μm diameter) were pretreated with consecutive solutions of SnCl2 and PdCl2 in HCl. Nickel was then electrolessly deposited onto these glass spheres, using dimethylamine-borane as a complexing agent. Tight control was kept over the temperature and pH of the solution in order to ensure ideal conditions. In this presentation the dielectric and magnetic microwave properties of composite materials formed with these Ni-coated particles will be reported.1.Zhao et al, Physica E, Vol. 9, pp. 679-685, 20012.Bowler, IEEE Trans. Dielectr. Electr. Insul., Vol. 13, pp. 703-711, 20063.Youngs et al, J. Phys. D: Appl. Phys., Vol. 39, pp. 1312-1325, 2006
10:45 AM - J8.4
TiO2 Nanoparticles/poly(acrylate) Elastomer Composite Films as Actuators
Jingqin Cui 2 1 , Ashok Maliakal 1 , Ilona Kretzschmar 2 Show Abstract
2 Chemical Engineering, city college, the city university of New York, New York, New York, United States, 1 , Bell Labs, Alcatel-Lucent, Murry Hill, New Jersey, United States
Electroactive polymers (EAP) of high dielectric constant and high electromechanical response are of great research interests due to their promising applications such as actuators, small-scale robotics, mini-pumps or charge storage capacitors. However the extensive application of EAP is presently limited by the required high driving electric fields. Therefore there is great need for new-types of polymer actuators that can operate at lower voltages in order to make practical devices using these interesting materials.Recent studies demonstrated that the incorporation of dielectric filling materials into polymers could achieve composites with both the elastic modulus of the pure polymer and the high dielectric constant, thereby greatly decreasing the electric fields required for the electromechanical strain [1,2].Our work presents the study of the electromechanical performance of low Tg poly(acrylate) such as poly(ethylene glycol phenyl ether acrylate) p(EGPEA) and copolymers of p(EGPEA) and poly(butyl acrylate) (pBA) which are loaded with high K titanium oxide (TiO2) nanoparticles. Polymer films with an array of micron-sized pillars are prepared with a replica molding technique and developed into electroactive polymer devices. A laser profile mapping setup is used to measure the electromechanical deformation. Our data shows that addition of TiO2 nanoparticles increases the strain achieved at 10MV/m by a factor of 3 to 7% as compared to unloaded polymer devices. Preliminary data on the performance of electromechanical film actuators loaded with surface-asymmetric spheres will also be discussed. Q.M. Zhang, H. Li, M. Poh, et al, Nature, 419, 284-287, 2002; F. Carpi and D. De rossi, IEEEE Trans. Dielec. Elec. Insul. 12, 835-842, 2005
11:30 AM - **J8.5
Aerosol Deposition Method For Ceramic Coating At Room Temperature: Current Status And Future Prospects.
J. Akedo 1 , T. Tsurumi 2 Show Abstract
1 , National Institute of Advanced Industrial Science and Technology, Tsukuba Ibaraki Japan, 2 Department of Metallurgy and Ceramics Science, Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo Japan
Miniaturization, cost reduction and higher performance in RF wireless communication products are demanded for constructing a ubiquitous computing network system. To realize the answer to these demands, we propose an organic built-up circuit board with various embedded passive ceramic component films for next-generation RF modules. The Aerosol Deposition (AD) Method ,  is a novel film coating technology where the impact of solid state particles can create a strongly adherent, high-density nano-crystalline ceramic film by gas blasting the submicron-sized ceramic particles on to a substrate. The deposition rate is 30 times faster than obtained with conventional thin film technology and the ceramic thin film can be deposited at room temperature. Initially, the new ceramics film creation mechanism “Room Temperature Impact Consolidation (RTIC)”  was discovered. It was investigated that the material particles were fractured and deformed into nano-crystallite sized particles of 10 to 30 nm and formed dense nano-crystal structures on impact with the substrate, with the activation of the newly formed surfaces on collision of particles dominating the inter-particle bonding. Based on the above deposition model, the optimum deposition condition was calibrated, as the results, α-Al2O3 and BaTiO3 fine particles were successfully compacted on metal and plastic substrates Through the development of new aerosol generating system using fluidization, BaTiO3 thin and thick films were successfully fabricated on Cu substrates at room temperature by employing an AD method. Their dielectric permittivity and dielectric loss tangent were enhanced to approximately 90~120 and 1~1.5% at 100 kHz, respectively. After annealing at 300oC in air, their dielectric permittivity also increased up to approximately 200~300. Finally, we could obtain the capacitance density of 3.9 nF/mm2 for the ADM-derived BaTiO3 film. In this presentation, the deposition mechanism of AD process, the fabrication results of embedded passive components and micro actuators will be also presented. J. Akedo, J. Am. Ceram. Soc., 89, 1834-1839 (2006). J. Akedo and M. Lebedev, Jpn. J. Appl. Phys., 38, 5397-5401 (1999).
12:00 PM - **J8.6
High Throughput Search Of Low k And Low Loss Dielectric Thin Films.
Ji-Won Choi 1 , Won-Kook Choi 2 , Nam Kang 3 , Wan-Keun Bang 4 , Seok-Jin Yoon 1 Show Abstract
1 Thin Film Materials Research Center, Korea Institute of Science and Technology, Seoul Korea (the Republic of), 2 Materials Science and Technology Research Division, Korea Institute of Science and Technology, Seoul Korea (the Republic of), 3 Electronic Materials & Packaging Research Center, KETI, Gyeonggi-do Korea (the Republic of), 4 , Samwon Vacuum Co., Ltd., Gyeonggi-do Korea (the Republic of)
Recently, dielectric thin films have been developed for ultra thin and highly integrated system level packaging. Higher signal transmission speed and embedded densities require dielectric thin film substrate due to increased switching speed and circuit density in thin 3-D module. To achieve the high signal transmission speed, dielectric thin films which have low dielectric constant are required because propagation delay time typically depends on the dielectric constant. Furthermore dielectric loss of thin films decides stability and performance of devices due to its leakage current. Therefore low dielectric constant and low dielectric loss thin films have to be developed.To develop dielectric compositions to meet these requirements, continuous composition spread (CCS) method was used to search optimum dielectric properties in this study. Dielectric constant of binary Al2O3-Ta2O5, Ta2O5-SiO2, and ternary Al2O3-Ta2O5-SiO2 compositions were deposited by off-axis reactive co-sputtering using 2 inch target planar magnetron sputter guns arranged at 90o intervals around a three inch-diameter Pt coated substrate (Pt (130 nm)/SiO2 (300 nm)/Si wafer). Al2O3 has low K(≈9) and relatively low dielectric loss, and Ta2O5 has relatively low K(≈23) and very low loss, and SiO2 has very low K(≈4) and relatively high loss. Dielectric properties of Al2O3-Ta2O5 showed low K(9.3-14.1) and low loss(0.00014-0.00032) at our feasibility test. Therefore, it is expected that compositions which have low K and very low dielectric loss can be achieved from continuous composition spread of these materials. Platinum counter electrodes, which have 130 nm thickness and 3.14x10-4 cm2 area, were deposited on dielectric thin films by e-beam evaporation to form MIM capacitors for electrical characterization. The dielectric properties were measured using an automated probe station. The capacitance and loss tangent of capacitors were measured at a frequency of 100 kHz and a signal level of 500 mVrms. The composition was inferred as a function of position using Rutherford backscattering spectroscopy along with independent calibration runs.