bluuebunny/crossref_metadata_2025_split huggingface dataset:
A composite process for eprom and eeprom and its reliability
Authors: Shiba Kazuyoshi , Kubota Katsuhiko , Kuroda Ken‐Ichi , Hara Yuji 
Published: July 2007

AbstractA process to form an IC with an EPROM (erasable programmable ROM) and EEPROM (electrically erasable PROM) was a developed and a module was tested. Fabricating a floating‐gate type EEPROM and the process to achieve high reliability in write/erase performance and the high data‐retention characteristic were investigated. The write/erase endurance is higher when the tunnel oxidation is carried out by wet oxidation than when carried out by dry oxidation.As the temperature for forming the inter‐polyoxide increases, the leakage current decreases but the write/erase endurance decreases. As the tunnel oxide film becomes thinner, the write/erase endurance decreases. The passivation layer has a great influence on the Vth window and data‐retention characteristics. When the passivation layer is a P‐SiN, the foregoing characteristics are poorer than when a PSG film is used. However, if PSG and P‐SiO films are formed under the P‐SiN film, the degradation of the forementioned characteristics decreases.
Fiber optic pattern recognition sensor using neural network
Authors: Aisawa Shigeki , Noguchi Kazuhiro , Matsumoto Takao 
Published: July 2007

AbstractA novel method for remote pattern recognition sensing through a multimode optical fiber using neural networks is proposed and tested experimentally. A neural network is used to recognize the original image from a pattern transmitted through the optical fiber. The experimental results show that the 26 alphabetic character patterns can be recognized correctly after transiting 30 m of multimode fiber (core diameter = 400 μm, numerical aperture = 0.39). To increase the tolerance for displaced patterns and recognition ability for rotational symmetrical patterns, the wavelength division multiplex method also is proposed. Experimental results confirm the efficiency of this method.
Semiconductor or vibration sensors using multiple cantilever beams with different lengths
Authors: Member Hideo Muro, , Member Shigeo Hoshino, 
Published: July 2007

AbstractSemiconductor vibration sensors incorporating ten polycrystalline silicon cantilever beams with different lengths and the detection circuitry on the same substrate have been developed. The sensors were designed to detect a resonance of each beam by capacitance change and to discriminate knockings precisely by outputting the vibration spectrum.This paper describes the structure of the sensors, the analysis of the characteristics, the fabrication process, and the measured results. The cantilever beams consist of triply stacked layers of Si3N4/p4poly‐Si/Si3N4 and are released from the substrate by etching a sacrificial layer of an undoped poly‐Si, where the warps of the beams are adjusted through thickness control of the upper silicon nitride layer. The measured resonant frequencies of the fabricated sensors were 5 to 14 kHz for the 1‐μm thick, 100‐μm wide beams with lengths of 510 to 310 μm, which agreed approximately with the values calculated using a simple model. The sensitivity at resonance depended on the ambient pressure and was about 10mV/G with Q of 100 at 5 × 10−6 torr. In the test using a one‐cycle engine, remarkable outputs were observed for knocking vibrations with peak frequencies near the resonant frequencies of the beams.
Characterization and design method for asymmetrical‐structure offset‐type broadside‐coupled strip lines having thick strip conductors and dielectric substrate
Authors: Nakajima Masayuki , Yamashita Eikichi 
Published: July 2007

AbstractFor asymmetrical‐structure offset‐type broadside‐coupled strip lines used for a tightly coupled directional coupler and a high‐Qtransmission line, an analysis method and a design method are proposed in which the strip conductor thickness and the presence of a dielectric substrate are taken into account. In the analysis, the rectangular boundary division method is used within the range of the quasi‐TEM approximation. By combining this analysis method with an algorithm using the secant method, the forementioned directional coupler is designed. A systematic optimization method for each design parameter needed in the design is described. Further, by means of the capacitance difference method, the attenuation constant due to the conductor loss of the offset‐type broadside‐coupled strip line is derived. The numerical results are presented graphically in the form of a coupling coefficient, mode impedance, effective relative permittivity and attenuation constant due to the conductor loss.
Properties of SiN films deposited by photo CVD and memory characteristics of MNOS structure
Authors: Kim Taehong , Ohnishi Kazunori 
Published: July 2007

AbstractSilicon nitride (SiN) film was deposited at substrate temperature of 100–400°C using a photo CVD technique with NH3 and SiH2Cl2 gases and ultraviolet (UV) light from a low‐pressure mercury lamp.Based on ESCA analysis, it has been clarified that the film is relatively Si‐rich, that the binding energy of Si2p changes from SiN bond to SiNO bond at the oxygen content of 23 percent and that the film deposited at 100°C changes from SiN to SiO2 structure after the deposition.In the measurement of I–V characteristics using metal‐SiN‐Si (MNS) structure, the film leakage current was small, but the film deposited at high‐substrate temperature had a large leakage current although the interface characteristics improved.From the characteristics as a nonvolatile memory using a metal‐SiN‐SiO2‐Si (MNOS) structure, it has been found that the SiN film deposited by the photo CVD method is useful for memory devices and the electron trap density increases with deposition temperature.
A simulation of high‐frequency mutually coupled circuit using bipolar transistors
Authors: Shigehiro Takanori , Nakamura Masataka , Yoneda Syojiro 
Published: July 2007

AbstractAs electronic and transmission circuits have decreased in size and been implemented as integrated circuits, a number of methods for simulating active inductors has been proposed. However, the simulation of an ideal transformer and a mutual induction circuit has not been fully realized. In particular, there is no method which deals with high‐frequency simulation of a mutual induction circuit that actually realizes the variable double‐tuned responses with a varying element that are related to the coupling coefficient.This paper proposes a new high‐frequency simulation circuit which has the following advantages:

All the transistors used in the circuit are of the npn type.
Two inductances (the self‐and mutual‐inductances) are realized using a bi‐directional differential current flowing in a single capacitor. These inductances can be independently set and adjusted.
(3) The circuit is configured symmetrically, whereby the right and left circuits are coupled using buffer transistors, in order to minimize their effect on one another.
In this paper we will first describe the fundamental principles of the proposed circuit. Then, taking into account the imperfection of the transistors, we will perform a circuit analysis over a high‐frequency range and discuss the results. As an application example we will use a double‐tuned circuit with a center frequency of 1 MHz. Finally, the feasibility of the proposed circuit will be confirmed using an experiment. Results indicate that the measured responses coincide with the calculated ones for single‐peak, maximum‐flat, and double‐humped cases.
Soft magnetic properties of CoNbZrN microcrystalline films produced by dc magnetron sputtering
Authors: Shimada Yutaka , Miyakawa Choji 
Published: July 2007

AbstractPreviously, it was stressed that the magnetically soft amorphous films lose their softness when nitrogen or oxygen is doped in the fabrication process. However, it has been reported that composition‐modulated nitride films maintain magnetic softness and exhibit remarkably high thermal stability. Furthermore, it has been reported that uniform nitride films with magnetic softness can be obtained when deposited by ion beam sputtering.In this paper, uniform nitride films deposited by dc magnetron sputtering are studied. DC magnetron sputtering is expected to have an effect similar to that of the nitride films in improvement of magnetic softness. The results of the analysis of nitrogen content and its chemical bonding and magnetic softness of the films are described. Furthermore, the transition process from the amorphous phase to the nanocrystalline phase and the structure of the crystalline phase are studied. The results suggest that the films have a magnetic structure different from that of the magnetically soft nanocrystalline materials reported so far.
Ir sensor using functional semiconducting fiber and application to human detection
Authors: Muto Norio , Miyayama Masaru , Yanagida Hiroaki , Kajiwara Teijiro , Mori Norihisa , Imai Yoshikazu , Harada Hirofumi , Ichikawa Hiroshi 
Published: July 2007

AbstractThe infrared (IR) sensor has recently become more important in many fields, and development of a conventional IR sensor with a fast IR response is needed. Both SiC fiber and carbon fiber have been found to be therm‐stor materials that have rapid thermal response. The present paper reports on the development of fibers for use in IR sensors, including the measurement of the fundamental fiber properties and thermal response characteristics to the IR radiation of IR sensors using fibers. Application in intelligent IR sensors, human body detection, and future developments are also reported.The IR response was affected markedly by fiber structure. A thermal time constant of 1.24 ms was observed in response to IR radiation from a 600‐K black‐body furnace. The thermistor constant of the fiber increased linearly with an increase in the electrical resistivity of the fiber; the output voltage of the IR sensor using a semiconducting fiber increased with an increasing thermistor constant. The IR sensor using functional semiconducting fiber with a larger thermistor constant detected intelligently in a room‐temperature environment both an immobile and a mobile human body, each of which had body temperatures that were lower and higher than the room temperature. The functional semiconducting fiber was found to be a promising material for intelligent IR sensor.
Geometrical theory of diffraction including corner diffractions with application to radiation pattern analysis of major angle corner reflector antenna
Authors: Zhang Xu , Inagaki Naoki , Kikuma Nobuyoshi 
Published: July 2007

AbstractThe major angle corner reflector antenna is characterized by a large half‐power value width in the magnetic plane and a large front‐to‐back ratio. This antenna is considered a candidate for the fixed‐state antenna for radio communication within a limited space being studied by the authors. The analysis of radiation patterns of antennas of this type traditionally has been carried out by the induced electromotive force (EMF) method. In such calculations, the errors in the sidelobes have been substantial.In the analysis of the radiation pattern in this paper, the corner diffraction formula derived previously and the approximate corner diffraction formula for a hollow wedge corner which is newly derived by an asymptotic calculation from the equivalent edge electric and magnetic currents in the UTD are included in the application of the GTD (Geometric Theory of Diffraction). It is shown that by this approach an accurate analysis can be performed in both the E‐ and H‐planes. It is confirmed that the results by the GTD, by the MM (moment method), and by the experiments agree well.
Neural network hardware with learning function using pulse‐density modulation
Authors: Eguchi Hirotoshi , Furuta Toshiyuki , Horiguchi Hiroyuki , Oteki Sugitaka 
Published: July 2007

AbstractTo adequately demonstrate the parallel distributed processing and self‐learning capabilities of neural networks, a realization in hardware is the most appropriate approach. Therefore, a pulse‐density type neuron model was proposed in view of its ease of implementation in hardware. In this model, symbols are transmitted as streams of pulses, and symbol values are represented by the pulse densities. In addition, symbol calculations are all done digitally. An algorithm was developed which enables learning by backpropagation in layered networks, and the efficacy of the proposed neuron model was established through a software simulation. Next, a hardware neuron is constructed on a digital circuit board and its feedforward and learning processes as well as its error backpropagation capability are demonstrated. Using this board, a prototype hardware neural network was constructed which does not require any software and which performed handwritten digit recognition and learning. Finally, this neuron board capabilities were integrated in LSI using a gate array. The possibility of its use in implementing future large‐scale networks is discussed.
Surface plasmon immunosensors
Authors: Sun Xiaochun , Matsui Yoshikazu , Shiokawa Showko , Kubota Hiroshi 
Published: July 2007

AbstractA surface plasmon is a charge density wave propagating along the interface between a metal on dielectric medium. Since the energy is concentrated at the interface, sensors that utilize the surface plasmon are extremely sensitive to both the charges in the dielectric properties and the geometry of the interface.A surface plasmon immunosensor to detect antibody and antigen immunoresponse has been developed. Here the sensitivity of the sensor is theoretically investigated and the experimental results of sensor sensitivity, the real‐time measurements and the problem of repeated utilization of the sensors are evaluated using α‐Feto‐protein (α‐FP) and goat IgG. In addition, the problem of deciding whether to use antibody or antigen as immobilized sensing medium is discussed based on the characteristics of surface plasmon and biomolecules. As a result, it is concluded that with an antigen immobilized sensor, the sensitivity is higher and the real‐time response can be detected.
Observation of the bonding interface between ALN ceramics and metal base with the ultrasonic imaging system
Authors: Takahashi Masaaki , Kurihara Yasutoshi , Yamada Kazuji , Musha Yoshinori 
Published: July 2007

AbstractDuring the thermal cycle test of semiconductor modules with Si chips, AlN ceramics and metal bases for heat sink connected to each other by soldering, the thermal resistance of some specimens increased in a comparatively short test period. By observing the interiors of these specimens using an ultrasonic survey imaging system, a strong reflected wave was observed at the solder connection joints of the AlN and the metal base. The area of this reflected wave was in the circumferential part of the sample at the initial stage but extended to the center with the thermal cycles.The reflected wave observed in these specimens was caused by a gap due to the breakage of solder because of the difference in thermal expansion coefficients between AIN and the metal base. It has been clarified that the reduction of the observed connection area agreed with the analytical estimation based on the thermal fatigue failure of solder, and the relationship between the reduction of the connection area and the increase of the thermal resistance also was clarified empirically. Moreover, it was confirmed that the ultrasonic imaging system is applicable to evaluation of the connecting conditions between semiconductor chips, ceramics substrate and metal bases because it can observe clearly the voids inside the solder which cause thermal resistance fluctuation.
A study of a resonant condition of symmetric triple‐barrier structures by using circuit theory
Authors: Ohtani Naoki , Nagai Nobuo , Suzuki Masakiyo , Miki Nobuhiro 
Published: July 2007

AbstractRecently, quantum effect devices have been studied extensively and new functional devices not observed in the conventional devices are expected. As a result, the necessity of developing a design method for superlattices is enhanced.The authors have proposed a method in which the multiple barrier structures are replaced with complex equivalent circuits. Using this method, it is now possible to treat the resonant tunneling effect from the viewpoint of circuit theory. It was shown that the network synthesis theory can be applied to the design of the superlattice. Although the resonant tunneling effect of a double‐barrier structure has been studied extensively for device applications, little attention has been given to the triple‐barrier structures.In this paper, numerical experiments are carried out with this complex‐valued equivalent circuit model so that the resonant conditions of the symmetric triple barrier are studied. To this end, the matching condition valid for a circuit symmetric right to left is applied to the equivalent circuit of a symmetric triple‐barrier structure so that its resonant condition is investigated. It is found that the electron energy that makes the impedance viewed at the center of the equivalent circuit purely resistive is the complete resonant level. It is shown also that this resonant condition can be understood easily by the use of the Smith chart.
Evaluation of cohesive property of carbon black in epoxy resin composite from the equivalent circuit in high‐frequency region
Authors: Nakamura Shuhei , Ito Atsushi , Sawa Goro , Kitagawa Keiichi , Tsubota Kazunari , Ikeda Masayuki 
Published: July 2007

AbstractWhen carbon black (CB) with high cohesiveness is used for a carbon‐black resin composite, the temperature coefficient of resin resistivity is negative and the increase in resin resistivity due to humidity is small. These symptoms are due to the balance between the mechanical change, such as thermal expansion and volume increase caused by humidity absorption and the bond strength between CBs. The bond strength between CBs is dependent on curing temperature. In this study, the cohesiveness of CBs which scatter in resin will be investigated by evaluating the electrical property in the high‐frequency region.The impedance of a CB‐resin composite was measured at frequencies up to 3 GHz and was expressed by the parallel equivalent circuit with resistance Rs and static capacitance Ce. Since residual resistance is present at frequencies up to 3 GHz, the equivalent circuit was replaced with the circuit with series resistance Rs and a parallel circuit with resistance RC and static capacitance CC. This equivalent circuit was investigated by the S parameter method.As the concentration CB increased, RS and RC rapidly decreased and CC increased. When CB particles were easily bonded together, RC was small and CC was high even if the concentration of CB was low. From the dependencies of RC and CC on the CB concentration and the temperature dependence of resistance, it was concluded that RC and CC provided information on the cohesiveness of CB.
Electrification properties of human body for walking‐motion
Authors: Fujiwara Osamu , Okazaki Masaru , Azakami Takashi 
Published: July 2007

AbstractDigital equipment with various high‐speed, low‐power ICs is vulnerable to electrostatic discharge (ESD) and a method to avoid this problem should be developed. Since ESD often is generated by a human while walking, the ESD generating mechanism must be well understood to prevent ESD.This paper proposes a method to estimate the generated charge by evaluating the potential of the human body while walking. Assuming that the basic human motions consist of the up and down movement of the feet, the potential of the human body and generated charges for every step were measured. As a result, it was found that the potential and charges in the human body caused by steps reach a steady state within 800 ms, the potential is lower than 700 V, and the charges are less than 100 nC.The capacitance of the human body changes according to motion and is around 200 pF. When one foot is raised, the body capacitance is 70 percent of that when both feet are grounded. The body potential is dependent on the kind of foot motion, that is, in continuous walk, the body potential is negative and its absolute value increases continuously. In stepping, the potential vibrates with a constant amplitude. These characteristics can be explained from the charging characteristics for the basic body motions.
Design and fabrication of a shielded‐velocity‐matched Ti:LiNbO3 optical modulator
Authors: Kawano Kenji , Nozawa Toshinori , Kitoh Tsutomu , Yanagibashi Mitsuaki , Jumonji Hiromichi , Noguchi Kazuto 
Published: July 2007

AbstractThis paper describes a shielded‐velocity‐matched Ti:LiNbO3 optical modulator which realizes a wide bandwidth with the velocity matching between the optical wave and the modulation microwave by placing a shielding conductor close to the coplanar waveguide traveling electrode through an air overlay.In the design of the traveling‐wave electrode, a quasi‐TEM approximation and a spectral domain approach with hybrid mode are used. From numerical analysis it has been found that the effective refractive indices of the microwave and the light wave can be matched by optimally setting the overlay thickness. It has also been found that the increase in the microwave propagation loss or decrease in the characteristic impedance can be suppressed by increasing the thickness of the SiO2 buffer layer. As for the optical waveguide, the design parameters have been clarified by using a newly developed modified step segment method.Based on these examinations, a Mach‐Zehnder intensity modulator and a phase modulator for the 1.5‐μm wavelength band have been designed and fabricated. As a result of measurement, the optical modulation bandwidth has been improved greatly to 20 GHz. As for the drive voltage, the intensity modulator uses 4.7 V and the phase modulator uses 6 V. The total insertion loss including the connector loss is 2.2 dB for the intensity modulator and 2 dB for the phase modulator. It has also been verified that the modulators have superior ambient stability.
A possibility of superhigh‐speed photodetection through frequency conversion
Authors: Choi Young‐Kyu , Wai Yee Mun , Nakajima Masamitsu 
Published: July 2007

AbstractIt is shown that even if the modulating frequency of a light is too high for direct detection, the signal can be extracted by frequency conversion at the same time as the detection by means of the nonlinearity of the APD. When this frequency conversion detection is applied to an optical receiver, the detection bandwidth can be increased while the configuration of the optical detection circuit and the signal processing in the subsequent stages are simplified. A fundamental analysis is carried out with an APD which is confirmed experimentally.
Design and performance of optical transfer splicing system using multifiber connectors
Authors: Kobayashi Hideo , Shimizu Masatoshi , Watanabe Ichiro , Maki Terufumi , Uenoya Takuya 
Published: July 2007

AbstractThe transfer splicing of optical fiber cables is performed at night using released circuits; this involves time‐consuming manual work. To achieve highly efficient optical cable transfer splicings, development of low‐loss transfer components is expected to speed up transfer operations. This in turn reduces interruption time and identification of cable fibers and also controls synchronization of each function and details required.This paper proposes an efficient system for the optical transfer splicing of the existing cables to the new ones. This system uses single‐mode multifiber connectors. The design method and related details of rapid transfer, fiber identification and synchronous transfer control are described. The transfer splicing characteristics of this newer, more efficient system are evaluated and it is verified experimentally that satisfactory results are possible.