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FUJI ELECTRIC JOURNAL March/2004 (Vol.77-No.2)
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Latest Trends of Research and Development |
Latest Trends of Research and Development
Noboru Furusho
With the expansion of globalization since 1990, the advantages of Japanese-made products have been fading due to increased competition in both domestic and international markets. To rectify this situation requires that Japanese-made products be provided with overwhelming competitive advantages. The keys to achieving this goal are the research and development of technology by the manufacturers. Fuji Electric Advanced Technology Co., Ltd. is focusing its efforts on expanding fundamental businesses by launching new products, shortening the incubation periods for new products and new business ventures, and increasing basic research in order to establish a solid foundation for continuous development.
Electrical Bistable Devices Using Organic Materials
Haruo Kawakami, Hisato Kato, Keisuke Yamashiro
Electrical bistable devices made from organic materials are being developed at Fuji Electric. In these devices, two stable values of conductance exist for a single voltage value. Promising applications include high-density memory devices and driving devices for organic electroluminescence display panels. High current density is obtained using a simple structure in which a layer of organic material, developed by Fuji Electric, is sandwiched between metal electrodes. Moreover, a high transition voltage of 20V, the highest value achieved in the industry, has been realized through the development of a new structure using these materials.
Development of Environmentally Conscious Products
Hirohiko Watanabe, Toshiyuki Kanno, Masaharu Furukawa
The date for compliance with collection and recycling regulations according to the EU's Waste Electrical and Electronic Equipment (WEEE) directive and the date on which usage of six materials (lead, mercury, cadmium, hexavalent chromium, and two types of specially designated bromine-based fire retardants) is banned according to the "Restriction of Hazardous Substances" (RoHS) directive have been decided as August 13, 2005 and July 1, 2006, respectively.
Fuji Electric is actively involved in the development of environmentally conscious products. Of the materials developed in compliance with the above regulations, this paper focuses on Fuji Electric's efforts and describes the material characteristics regarding the two themes of reactive non-halogen fire-resistant materials for molding resin and lead-free solder materials for use in lead-free electronic devices.
High-speed Synthesis of Dielectric Thin Film Materials by Combinatorial Film Deposition
Yoshiyuki Yonezawa, Yoshinori Konishi, Ryosuke Shimizu
Fuji Electric is working on the development of new dielectric thin films with the prospect of application to integrated thin film capacitors and oxide thin film devices. In consideration of application to capacitors, the targeted specification calls for a lead-free material having both a high dielectric constant (>1,200) and high breakdown voltage (>1 MV/cm). Fuji Electric is working to increase the dielectric constants of conventional lead-free materials and also to develop SnTiO3, a new dielectric material, charge-transfer type dielectric materials, and the like, but this type of search involving the synthesis and evaluation of new materials is extremely labor and time intensive. To solve this problem, combinatorial thin film technology, a high-speed screening technique said to compress 20 years into three months, has been advocated. This paper presents an overview of combinatorial thin film technology and its use at Fuji Electric.
A New Semiconductor Device with Trench Technology
Yoshihiko Nagayasu, Naoto Fujishima, Kunio Mochizuki
By using a trench structure to enable the three-dimensional utilization of a silicon substrate, Fuji Electric has developed 700V-class high voltage lateral MOS technology that exhibits the lowest output on-resistance in the industry. In Fuji Electric's proprietary method for manufacture, a deep (20
m) stripe-shaped trench having a high aspect
ratio is formed, ions are injected obliquely to create an offset drain
region along the trench, and then an insulating layer is formed by oxidation
and CVD. This method increases the cell density and realizes
the best output on-resistance of 11
mm2 (device breakdown voltage
of 750V), which is the approximately 30% less than that of a conventional
high voltage MOSFET.
Structural Control Method for Perpendicular Magnetic Recording Film
Shunji Takenoiri, Yasushi Sakai, Sadayuki Watanabe
Development efforts to commercialize perpendicular magnetic recording film are intensifying. The granular media of CoPtCr-SiO2 that Fuji Electric uses as a magnetic layer is a promising high-density recording media that aims to achieve 200Gbits/in2. However, in order to obtain excellent characteristics in a recording medium, the magnetic crystal grains must be made uniform, miniaturized and magnetically separated. This paper presents an example in which the size of magnetic crystal grains and the structure that magnetically separates them were controlled by controlling the size of Ru crystal grains and the surface structure in a CoPtCr-SiO2 medium that uses Ru in the foundation layer.
Rapid Inspection Technology for Microorganisms
Naohiro Noda, Takamasa Asano, Yujiro Kitaide
In the food, pharmaceutical and many other industries, the capability to inspect microorganisms rapidly is required. Fuji Electric has studied the micro-colony technique as a method for quickly and easily inspecting microorganisms. From the results of the study, we learned by using the micro-colony technique it is possible to detect contamination by bacteria that causes food poisoning, heat-resistant bacteria, and fungi. The time required for detection was much shorter than in the case of using the conventional culture method, and the type of microorganism could be determined from the shape of the micro-colony. Moreover, it is predicted that automated machines will be used in the future to detect colonies quickly and easily.
Top-emitting CCM-organic Light Emitting Displays
Hiroshi Kimura
A top-emitting device has been developed for CCM-AM-OLED displays. The fabrication method for the transparent cathodes at the upper portion of the top-emitting device using opposing-targets sputtering and the optical design method of the OLED device structure utilizing optical simulation are introduced. A prototype of the CCM topemitting device was fabricated by laminating a CCM substrate to a topemitting device.
Wireless Link Design for Contactless Smart Cards
Shiro Kondo, Tatsuyuki Shikura
Recently, contactless smart card applications have rapidly been spreading in popularity, and various types of cards and differently shaped media such as wristbands, watches and cell phones containing built-in ICs for smart cards are appearing on the market. Hence the inter-connectivity between such media and reading and writing devices (RWs) is an important issue. Focusing on the wireless communications technology for contactless smart cards, this paper describes design concepts for the data link and physical layers as well as specific examples of Fuji Electric's development and design methodology.
Recent Optimization Techniques and Applications to Customer Solutions
Shinji Kitagawa, Michio Takenaka, Yoshikazu Fukuyama
This paper introduces recent optimization techniques developed at Fuji Electric and applications of those techniques to customer solutions. We have developed optimization techniques that are metaheuristic techniques and techniques based on the theory of stability of non-linear systems, and these techniques enable various customer solutions including a reduction in operating costs, optimization of control quality, and device miniaturization. Sensor-based diagnosis in a system for the optimal operation of an energy plant is presented as an example. Fuji Electric will continue to develop optimization techniques to realize customer solutions.
High-efficiency Power Conversion with Matrix Converter
Junichi Itoh, Akihiro Odaka, Ikuya Sato
Since a matrix converter directly converts arbitrary AC voltages from an AC power source, its conversion efficiency is higher than that of an inverter. Moreover, the matrix converter has the characteristics of small size and long operating life, and it does not require an electrolytic capacitor in an intermediate DC stage. Fuji Electric has developed new technology for commercializing matrix converters and this paper describes: (1) a reverse blocking IGBT that achieves AC switching with low loss, (2) protection technology that enables smaller sizes and higher efficiency, and (3) control technology based on a virtual ACDC-AC system that simplifies the application of conventional inverter control.
Welding Technology for Different Steel Materials in a Steam Turbine Rotor
Seiji Imamura, Sakae Izumi, Minoru Iizuka
In high-temperature high-pressure and low-temperature low-pressure steam turbine rotors, different materials are utilized that have mechanical properties suitable for the respective conditions of use. Fuji Electric has developed narrow gap welding technology for different steel materials to integrate both rotors by welding. A prototype rotor of actual size was made, first layer welding and multi-layer welding were implemented, and a series of verification tests such as nondestructive tests and mechanical properties tests were performed. Fuji Electric has also developed cladding by welding technology (technology for welding different types of materials) as a technique for repairing the grooved part of rotor blades in a geothermal turbine. Fuji Electric aims to apply this welding technology to single-casing reheat/non-reheat turbine products and to the repair of geothermal rotors.
Nano-level Crystal Structure Analyses for Semiconductor Devices and Magnetic Recording Media using Synchrotron Radiation
Ryohei Tanuma, Toshikazu Kubo, Michio Ohsawa
Using the industrial-use beamlines that were established at SPring-8 by a consortium of 13 companies, the microscopic strain accompanied by Si trench processing and the crystalline structures of extremely thin film magnetic recording media were analyzed. In the case of the former, X-rays were expanded with a Fresnel zone plate to successfully measure strain of 10-5 with submicron spatial resolution. For the latter, a grazing incidence X-ray diffraction technique was used to analyze the crystalline structure of a 0.8nm Ru layer and to detect the fcc phase in a 20nm hcp magnetic layer. Use of the SPring-8 facilities enable nano-level analysis of crystalline structures.
Technique for Numerical Simulation of the Etching Process
Kimihisa Kaneko
This paper describes a technique for numerical simulation of the etching process during semiconductor manufacture. The numerical analysis utilizes an equation of continuity, the Navier-Stokes equation and a diffusion equation. Furthermore, the ALE method is applied to the change in interface shape due to etching of the thin film. A timevarying profile of an etching cross-section simulated by this technique was largely in agreement with actual observed results, demonstrating that this numerical analysis technique can be used effectively to predict the actual etching form.
3-D Electromagnetic Computation for Zero Phasesequence Current Transformers
Kota Matsumoto, Takahiro Kudo, Hisanobu Asano
Earth leakage circuit breakers are being made smaller and in compliance with major global standards. Electromagnetic analysis is used in practical applications as 3D large-scale analysis made possible by the combination of various developmental methods and the higher performance of computers. Using the integral element method, we have applied electromagnetic analysis to zero phase-sequence current transformers for earth leakage circuit breakers. The ground fault characteristics, single pole characteristic and equilibrium characteristic of a 3-pole zero phase-sequence current transformer were verified by analysis and measurement, and those results are reported in this paper. Each of the characteristics was obtained with a level of accuracy sufficient for practical use. In the future, we plan to apply this technology to the development of 4-pole devices and to effectively use electromagnetic analysis.
Technology for Simulating Power Electronics Circuit Structures
Satoki Takizawa, Gjini Orges
In the field of power electronics, advances in power semiconductors and the realization of high-speed switching, in particular, are enabling power converters to be made smaller and with higher performance. However, as switching speeds increase, the problems of higher surge voltages and radiation noise are becoming more conspicuous. In response to these problems, Fuji Electric is studying ways to lower surge voltages and radiation noise by analyzing electromagnetic fields through the simulation of the internal structures of power semiconductor modules and the simulation of power circuit bus bar structures. This paper describes examples of those studies.
Optimal Operation of Energy Utility Equipment and its Application to a Practical System
Donghui Xiang, Tooru Kawamori, Yoshikazu Fukuyama
Various types of energies such as electrical, thermal, steam energies and compressed air are required in factories, large offices, and hospitals. These energies are produced by various energy utility equipment such as cogeneration systems (CGSs), boilers, refrigerators, and compressors. This paper describes Fuji Electric's unique solution for total optimal operation of energy utility equipment, and shows an overview of the technologies utilized in the solution. In addition, a practical control system of the optimal operation for production facilities, which has been developed by a Toyota Motor Corporation and Fuji Electric jointly, is presented.
