Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
Low energy density in conventional capacitors severely limits efforts to miniaturize power electronics and imposes design limitations on electronics in general. We have successfully applied physical vapor deposition technology to greatly increase capacitor energy density. The high dielectric breakdown strength we have achieved in alumina thin films allows high energy density to be achieved with this moderately low dielectric constant material. The small temperature dependence of the dielectric constant, and the high reliability, high resistivity, and low dielectric loss of Al 2 O 3, make it even more appealing. We have constructed single dielectric layer thin film capacitors and shown that they can be stacked to form multilayered structures with no loss in yield for a given capacitance. Control of film growth morphology is critical for achieving the smooth, high quality interfaces between metal and dielectric necessary for device operation at high electric fields. Most importantly, high rate deposition with extremely low particle generation is essential for achieving high energy storage at a reasonable cost. This has been achieved by reactive magnetron sputtering in which the reaction to form the dielectric oxide has been confined to the deposition surface. By this technique we have achieved a yield of over 50% for 1 cm 2 devices with an energy density of 14 J per cubic centimeter of Al 2 O 3 dielectric material in 1.2 kV, 4 nF devices. By further reducing defect density and increasing the dielectric constant of the material, we will be able to increase capacitance and construct high energy density devices to meet the requirements of applications in power electronics.
Author: James N. Reck Publisher: ISBN: Category : Capacitors Languages : en Pages : 220
Book Description
"Dielectric thin films of either TiO2 or BaTiO3 were sputtered in O2/Ar plasmas on Si wafers to thicknesses ranging from approximately 25 to 200 nm with patterned Ni or Pt electrodes sputtered in Ar plasmas at thicknesses from about 20 to 250 nm to form nano-capacitors. Statistical design of experiments (DOE) was used to determine the effects of the deposition power, plasma composition, and deposition temperature on the measured electrical properties of the nano-capacitors. Additional tests to determine the effects of the dielectric and electrode thickness on the measured dielectric responses of the devices were also undertaken. Characterization was performed with a combination of direct current (DC) and alternating current (AC) testing methods including AC impedance, coercive field and leakage current versus voltage, scanning electron microscopy, transmission electron microscopy (TEM), x-ray diffraction (XRD), x-ray photoelectron spectroscopy, focused ion beam microscopy, and atomic force microscopy. The dielectric properties were found to depend on complex interactions of the process variables that could be modeled using statistical software. The permittivity was found to range from 100 to 10,000 with losses between 0.013 and 0.570. The resistance at 1 V DC varied from approximately 1.5 to 360 G[Omega], and either a ferroelectric or paraelectric hysteretic response was observed for all specimens tested. Chemical analyses showed the films to be oxygen rich, while XRD and TEM data indicated the BaTiO3 was amorphous. The electrical, chemical, and microstructural properties were found to depend on the sputtering conditions of the BaTiO3, dielectric thickness, electrode material choice, and the electrode thickness. Collectively, the results indicated that the properties of nanometer thick dielectric and electrode materials have a significant impact on the measured electrical properties"--Abstract, leaf iv.
Author: Jain Pushkar Publisher: Springer Science & Business Media ISBN: 1441991441 Category : Technology & Engineering Languages : en Pages : 164
Book Description
Thin-Film Capacitors for Packaged Electronics deals with the capacitors of a wanted kind, still needed and capable of keeping pace with the demands posed by ever greater levels of integration. It spans a wide range of topics, from materials properties to limits of what's the best one can achieve in capacitor properties to process modeling to application examples. Some of the topics covered are the following: -Novel insights into fundamental relationships between dielectric constant and the breakdown field of materials and related capacitance density and breakdown voltage of capacitor structures, -Electrical characterization techniques for a wide range of frequencies (1 kHz to 20 GHz), -Process modeling to determine stable operating points, -Prevention of metal (Cu) diffusion into the dielectric, -Measurements and modeling of the dielectric micro-roughness.
Author: Guneet Sethi Publisher: LAP Lambert Academic Publishing ISBN: 9783838399881 Category : Capacitors Languages : en Pages : 192
Book Description
Pulsed power applications involve transformation of electrical energy into high-peak power pulses through capacitors. There is an immediate need for fast-response capacitors with decreased volume, weight, and cost for pulsed power applications and power distribution systems. This research challenge is dominated by energy density. Energy density is directly related to dielectric properties such as dielectric polarization, conductivity and breakdown strength of the capacitor dielectric. This work correlates processing and microstructure of single and multiple component dielectric films with their dielectric properties. The inorganic materials studied here include zirconium oxide and tantalum pentoxide reactive sputtered films. Oxide films were combined with different polymers (polyvinyldene flouride-triflouroethylene, polypropylene and polyethylene terephthalate) to produce two different kinds of laminate composites - oxide on polymer and polymer on oxide. Permittivity and conductivity differences in the polymer and oxide films result in an impedance contrast which was modeled through Monte Carlo method in addition to the experimental characterization.
Author: Bruce A. Tuttle Publisher: John Wiley & Sons ISBN: 1118407229 Category : Technology & Engineering Languages : en Pages : 86
Book Description
Advances in synthesis and characterization of dielectric, piezoelectric and ferroelectric thin films are included in this volume. Dielectric, piezoelectric and ferroelectric thin films have a tremendous impact on a variety of commercial and military systems including tunable microwave devices, memories, MEMS devices, actuators and sensors. Recent work on piezoelectric characterization, AFE to FE dielectric phase transformation dielectrics, solution and vapor deposited thin films, and materials integration are among the topics included. Novel approaches to nanostructuring, characterization of material properties and physical responses at the nanoscale also is included.
Author: Publisher: ISBN: Category : Aeronautics Languages : en Pages : 456
Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Author: Kazufumi Kobashi Publisher: Woodhead Publishing ISBN: 008102889X Category : Science Languages : en Pages : 312
Book Description
Microsupercapacitors systematically guides the reader through the key materials, characterization techniques, performance factors and potential applications and benefits to society of this emerging electrical energy storage solution. The book reviews the technical challenges in scaling down supercapacitors, covering materials, performance, design and applications perspectives. Sections provide a fundamental understanding of microsupercapacitors and compare them to existing energy storage technologies. Final discussions consider the factors that impact performance, potential tactics to improve performance, barriers to implementation, emerging solutions to those barriers, and a future outlook. This book will be of particular interest to materials scientists and engineers working in academia, research and development. Provides a concise introduction of the fundamental science, related technological challenges, and solutions that microsupercapacitors can offer Compares microsupercapacitors with current technologies Reviews the applications of new strategies and the challenge of scaling down supercapacitors Covers the most relevant applications, including energy storage, energy harvesting, sensors and biomedical devices
Author: 
Author: James N. Reck
Author: Jain Pushkar
Author: Kuo-Chuan Liu
Author: Guneet Sethi
Author: Bruce A. Tuttle
Author: 
Author: 
Author: 
Author: Kazufumi Kobashi