FUJI ELECTRIC JOURNAL September/2004 (Vol.77-No.5)

TOP PAGE 1. Semiconductors
2. Radiation Monitoring Systems


Fuji Electric's Semiconductors: Current Status and Future Outlook
Hirokazu Kaneda, Akinori Matsuda
In the field of power electronics, Fuji Electric offers specialized semiconductor products for controlling electric power. These devices include discreet semiconductor devices such as diodes and MOSFETs, as well as IGBT modules and power ICs. Fuji Electric is focusing on applications in the strategic markets of industrial, automotive and information & power supply equipment. This paper presents an overview of Fuji's main products, core technologies and future trends of these markets.


U-series of IGBT Modules
Shuji Miyashita
Power conversion equipment, typified by general-purpose inverters and uninterruptable power supplies, are subject to constant requests for higher efficiency, smaller size, lower cost and quieter operation. Power semiconductor devices used in the equipment are required to have high performance, low cost and high reliability, and a 5th generation IGBT module (U-series), which provides a dramatic performance improvement over the 4th generation IGBT module (Sseries), has been developed. This paper introduces the product line of U-series IGBT modules and describes the latest device technologies, including NPT, trench-gate, field-stop and new FWD structures.


U-series of IGBT-IPMs (600V)
Kiyoshi Sekigawa, Hiroshi Endo, Hiroki Wakimoto
Fuji Electric has developed a 600V series of U-IPMs (20-160A). A dramatic decrease in steady-state loss is achieved by using a trench gate structure IGBT. Turn-on loss has also been reduced through the use of a newly developed FWD chip that realizes soft recovery and achieves higher di/dt without an increase in noise. In practical applications, the replacement of R-IPMs with the abovementioned U-IPMs enables the carrier frequency to be increased by a factor of two.


Development of a Next-generation IGBT Module Using a New Insulating Substrate
Yoshitaka Nishimura, Eiji Mochizuki, Yoshikazu Takahashi
Due to the recent demand for energy-efficient electronic products, IGBT modules are being used not only in industrial applications but also in home electronic appliances. Accordingly, in addition to the obvious market demands for low cost and high reliability, IGBT modules are also required to be lightweight and compact. In response to these needs, an insulating substrate having low thermal resistance and high strength was developed. This paper introduces the next-generation IGBT module that utilizes this new insulating substrate and achieves 30% better thermal resistance than prior comparable structures.


Study of Gate Oxide Film Formation for Power Semiconductor Devices
Ryosuke Matsumoto, Hirohisa Katoh
As silicon devices scale down, the application of ultra-thin oxide films has recently been attracting attention. In power devices such as MOSFETs and IGBTs, sometimes they are applied very thick gate oxide films and high temperature annealing is sometimes required in certain processes, various phenomena occur which are not observed in the application of ultra-thin oxide films. This paper reports the results of our investigation into the relationship between the electrical characteristics of power devices and the gate oxide film formation conditions such as oxidation method, film thickness and annealing method.


High Pressure Sensor Using One Chip Technology
Katsumichi Ueyanagi, Shigeru Shinoda, Kimihiro Ashino
In response to the expanding range of applications for high-pressure sensors to automotive and industrial applications, Fuji Electric has developed the world's smallest one-chip high-pressure sensor cell. This paper presents an overview of the product, describes design considerations for achieving the desired pressure resistance, and discusses product performance and reliability considerations. The newly developed high-pressure sensor cell is suitable for applications in the range of 1 to 5MPa, and is ideally suited as a high-pressure sensor for air conditioner and oil pressure control applications.


Low IR Schottky Barrier Diode Series
Mitsuhiro Kakefu, Masaki Ichinose
With the rapidly advancing trends toward the smaller size, lighter weight and higher performance electronic devices, the environment in which semiconductor devices are used is becoming more severe, especially in devices such as AC adapters for which the trends toward miniaturization and higher output are particularly noticeable. In response, Fuji Electric has commercially produced a low IR-SBD that is ideally suited for use in the secondary source rectification of switching power supplies in a high temperature environment. In order to optimize the characteristics of chip specific resistance and thickness, guard ring concentration, diffusion depth and barrier metal, IR has been reduced by approximately a factor of 10 compared to the conventional SBD and the increase in VF has been suppressed to the maximum extent possible so as to reduce power dissipation and to increase the maximum operating temperature.


60V-class Synchronous Buck Regulator Control ICs with Internal High Voltage MOSFET Switches
Masanari Fujii, Tamotsu Yoneda
In recent years, electronic devices have increasingly been made with smaller size, lighter weight and higher performance. The power supplies for driving these electronic devices are required to have a small size, high output and high efficiency. To meet these needs, Fuji Electric has developed and commercialized 3-channel or 2-channel output type buck DC-DC converter ICs "FA7726F and FA7730F" that contain an internal low on-resistance high-voltage power MOSFET on their main side and on their synchronous regulator side respectively. This paper introduces the characteristics of these control ICs and describes example circuit applications.


Medium-voltage MOSFETs for PDP-use
Yukihito Hara, Masanori Inoue
Large-screen high-definitions plasma display panels (PDPs) are rapidly growing in popularity. Targeting the sustain circuit, in which there is tremendous need for low on-resistance, Fuji Electric has newly developed a line-up of 150 to 300V SuperFAP-G devices. In response to requests for even smaller sizes and higher efficiency, Fuji has developed low on-resistance trench MOSFET technology. This paper introduces Fuji Electric's line-up of MOSFETs for PDPs and presents their characteristics.


PDP Scan Driver IC
Hideto Kobayashi, Gen Tada, Hitoshi Sumida
As flat panel displays (FPDs) increase in popularity, competition is intensifying among the various types of FPDs (LCDs, PDPs and projectors). For PDPs, performance improvements such as lower current consumption and higher luminous efficiency, as well as lower cost are needed. In response to these market needs, Fuji Electric has developed and commercialized technology that enables a scan driver IC having high current flow and low output on-resistance to be supplied at low cost.


Device and Process Technologies for PDP Driver ICs
Hitoshi Sumida
This paper introduces Fuji Electric's device and process technologies for plasma display panel (PDP) driver ICs. PDP driver ICs can be categorized as either address driver ICs or scan driver ICs. Isolation techniques, process technology and high-voltage lateral device technology are described for each type of IC. Technical trends in the development of both types of driver ICs at Fuji Electric are also discussed.


Current Trends in Radiation Monitoring System
Etsuo Kono
Radiation monitoring systems are installed to monitor radiation and radioisotopes (RI) at nuclear power plants, hospitals and research laboratories. Recently digital signal processing technology is adopted in them in order to do more precise measurements of radiation. Silicon semiconductor detectors, which can detect gamma, alpha and beta rays and neutrons, are replacing the conventional radiation detectors in radiation monitoring systems. A new radiation monitor suitable for measuring neutrons is being developed for use in nuclear fuel processing plants and accelerator facilities.


Personal Dose Monitoring System
Kei Aoyama, Osamu Ueda, Takeshi Kawamura
The integration of an electronic personal dosemeter in a personal monitoring system is expected to enable the real-time evaluation of measured values, achieve higher efficiency and realize other such advantages. Fuji Electric has developed an electronic personal dosemeter capable of measuring gamma rays (X-rays), beta rays and neutrons, and has realized a monitoring system that integrates this electronic personal dosemeter with a doorway-monitoring device. A radiation source calibration device conforming to JIS has also been developed. In the future, Fuji Electric intends to develop low cost, high precision and easy-to-use products for use at a wide range of facilities.


Environmental Radiation Monitoring System
Toshihiro Takagi, Osamu Kimura, Atushi Minagoshi
At nuclear power plants, the dose rate of environmental gamma radiations in the vicinity of the surrounding monitored areas and in the neighboring towns must be measured and monitored continuously. Environmental radiation monitoring system are critically important systems that continuously measure the environmental gamma radiations dose rates at specified measurement points and transmit that measurement data in real-time to a central control room where changes in the environmental radiation conditions are monitored centrally. Moreover, the disclosure of this measurement data enables the public to gain an understanding of the operation of the power plant. This paper introduces Fuji Electric's latest environmental radiation monitoring system.


Environmental Radiation Measuring Equipment
Hironobu Kobayashi, Tsuyoshi Sakamaki, Kaoru Masui
Nuclear power plants, research laboratories and medical facilities use a wide variety of radiological instruments and devices for radiation monitoring and control. Fuji Electric supplies a variety of radiological instruments and devices for diverse uses. This paper introduces the following two devices recently developed by Fuji Electric as environmental radiation monitors.
(1) An environmental dosimeter for low-level radiation featuring a nearly 100-fold increase in sensitivity compared with the conventional detectable level
(2) A transportable monitoring post equipped with a wider-range NaI (Tl) scintillation probe



Radioactive Contamination Monitor
Toru Hasegawa, Tadao Hashimoto, Manabu Hashimoto
At nuclear power plants, in order to prevent radioactive materials from spreading contamination outside the radiation control area, the surface contamination of all material transferred outside the control area is monitored. This paper presents an overview and describes features of: (1) personnel surface contamination monitoring assemblies for measuring the surface contamination on workers, (2) articles surface contamination monitoring assemblies for measuring the surface contamination on articles of all sizes, (3) laundry monitors for measuring the surface contamination on worker clothes worn inside the control area, (4) whole-body counters for measuring the worker's internal exposure, and (5) hand-foot-clothing contamination monitors for measuring the surface contamination on hands, feet and clothing.


Large-scale Radiation Monitoring System
Toshiaki Fujimoto, Katsuhito Ito, Sadao Nakashima
Nuclear facilities monitor radiation in order to protect workers and residents of neighboring communities from radiation exposure. Radiation monitoring systems are extremely important systems that continuously monitoring the radiation conditions within a facility and the radioactivity concentration in gaseous and liquid waste emitted from that facility. Fuji Electric has developed a sophisticated and highly reliable large-scale radiation monitoring system in which radiation detectors, provided with sophisticated and specific functionality for measuring radiation, are distributed at various locations throughout each site, data is transmitted via an Ethernet to a control room and a UNIX server is used for data processing.


Radiation Control Computer System
Eiichi Mihoya, Kenichi Tanabe, Michio Akashi
Fuji Electric has adopted for the first time a browser-based screen display developed for use by the nuclear power plants of electric power companies and has deployed a detailed workflow function that corresponds to the radiation control. This system was installed at the Tomari Power Station of Hokkaido Electric Power Co.,Inc. in March 2003, and enables the user to drastically reduce administrative paperwork, which including filings and notifications. Moreover, the capability has been provided for partner companies to extract company data in their desired format. Additionally, monitoring functions have been strengthened and an auto-alarm function provided in case of error with the system's status or managed data.


Radiation Monitoring System
Masaaki Satou, Hiroyuki Mizuno, Takashi Yabutani
This paper introduces a radiation monitoring system for use at facilities such as universities, hospitals and research laboratories where radioisotopes (RIs) are used. RI used by medical institutions and research laboratories has increased in recent years. Meanwhile, as society becomes more concerned about the environment, radiation monitoring systems are becoming increasingly important. An overview of this system and recent trends are provided.


Industrial Measurement Instruments that Use Radioisotopes
Asao Monno
An example of a large-scale system for controlling hot rolling, and recent developments for a gamma-ray thickness gauge for the innermill housing of a plate and a thickness gauge for a hot seamless tube mill are introduced. The dramatically higher speed response, versatile intelligent elements, larger data capacity and formation of a database are advantages of these instruments over conventional devices. Moreover, Fuji Electric's industrial measuring instruments that use radioisotopes are manufactured and marketed to be compatible with those of Hitachi, and we have already compiled a track record of many deliveries.

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