bluuebunny/crossref_metadata_2025_split huggingface dataset:
Annealing technology under arsenic overpressure for GaAs LSI–influence on dislocation and threshold voltage
Authors: Egawa Takashi , Sano Yoshiaki , Nakamura Hiroshi , Kaminishi Katsuzo 
Published: July 2007

AbstractSince the microscopic uniformity of the threshold voltage (Vth) of an FET is important to obtain GaAs LSI, the cause of the threshold voltage uniformity was researched by investigating the annealing dependencies of the dislocations in the semiinsulating substrate of LEC GaAs and the microscopic uniformity ofVth. Annealing under arsenic overpressure decreased the dislocation density on the substrate surface and formed a uniform distribution of dislocations. This is believed to be caused by the supply of arsenic to the substrate surface. When annealing was carried out under low arsenic pressure,Vthshifted toward the negative direction at the area with clustered pits, and a clear dislocation network was formed. On the other hand, when annealing was carried out under arsenic overpressure using arsene, the shift ofVthin a negative direction becomes small andVthwas distributed uniformly. When annealing was carried out using a protective PCVD SiNxfilm, the distribution ofVthwas consistently uniform, regardless of the dislocation distribution. As described in the preceding, it was found that a high concentration of AsGaexists in the area of the clustered pits, the uniformity ofVthis independent of the dislocation density but dependent on the stoichiometry of the substrate prior to or after annealing, and the distribution ofVthbecomes more uniform with an increase of arsenic concentration.
A MESFET model for the design of GaAs digital integrated circuits
Authors: Tanaka Koutarou , Kawakami Yasushi 
Published: July 2007

AbstractAs in the case of Si IC's, it is important to carry out circuit simulation in the development of GaAs digital IC's. This paper discusses a GaAs MESFET model for digital IC design. Since in the Shichman‐Hodges model the parameters are obtained only for the saturation region of the drain current, the model is not accurate in the nonsaturation region. Therefore, we utilized additional parameters in the model for the nonsaturation region to increase accuracy. Approximating the potential distribution in an MESFET channel by that in the MOSFET model, the internal capacitance was obtained analytically as a function of the gate and drain voltages. Using the model obtained as described in the foregoing, the transfer characteristic and operational speed of the DCFL circuit were calculated and the results were in excellent agreement with the experimental results.
Study on GaAs monolithic dynamic divider
Authors: Shigaki Masafumi , Yokogawa Shigeru 
Published: July 2007

AbstractThe GaAs monolithic dynamic divider, a high speed divider for microwave phase locked oscillators, has been studied. It can be operated at a higher speed than static dividers. The load in the inverter section is a passive resistor. Improved circuit topology at interstage buffers and reduction of gate resistance by the Au/WSi self‐aligned process have been used for superior characteristics of a single FET. For a 1 μm gate length, both division and frequencies ranging from 4.3 GHz to 7.3 GHz have been observed. As a system application, the divider has been implemented in a 13 GHz frequency synthesizer of oscillator‐multiplier type. The divider has been operated in the 6.5 GHz band and an operation with 1 MHz steps has been confirmed at the 13 GHz band. The phase noise has been 90 dBc/Hz at the off‐carrier frequency of 10 kHz. This value is sufficient for conventional microwave circuits.
Multilayer thin‐film waveguide polarizer with metal cladding
Authors: Kato Isamu , Hara Ryoichi , Sugiyama Yasuyuki 
Published: July 2007

AbstractA metal‐clad optical waveguide can be used as a polarizer which passes the TE mode but blocks the TM mode. Numerous studies have been reported on metal loaded on slab waveguides. However, little has been reported on practical three‐dimensional waveguides. In this paper, a multilayered guided polarizer is fabricated by loading an AL film on a polymer thin‐film waveguide via a low‐index buffer layer. The polarization characteristics have been studied. In the case of a slab waveguide, the extinction of ratio of the guided wave intensities of the TE and TM modes increases with the film thickness of the buffer layer. It becomes a maximum of 34 dB for a film thickness of 0.18 μm and then decreases gradually. In the case of three‐dimensional waveguide, the electric field distribution of the hybrid guided mode is a mixture of the TE and TM modes. Hence, the extinction ratio is somewhat lower. However, the buffer layer thickness dependence of the extinction ratio is about the same as the one in the slabe waveguide. In the case of waveguide widths of 50 and 5 μm, the extinction ratio of the polarizer has been 30 and 22 dB, respectively, for a buffer layer thickness of 0.18 μm.
Monte carlo simulation of energy broadening in electron beams
Authors: Matsuda Jin‐Ichi , Kubo Mitsunori , Iriguchi Chiharu , Kato Kazuo , Masuda Takao 
Published: July 2007

AbstractA numerical analysis based on the Monte Carlo simulation has been carried out for the space‐charge effect affecting the longitudinal energy broadening of the electron beams. The collisions of the electrons are treated as a many‐body problem. For (1) a cross‐over model, and (2) a triode electrode gun model, the electron beam current dependence of the energy distribution and the current density distribution is studied. It is found that the anomalous energy broadening that has not been explained fully by the existing theoretical analysis based on the two‐body problem approximation can now be understood quantitatively. The validity of our analysis method is thus demonstrated.
Proposal for a fiber‐optic endlessly rotatable fractional wave device and its applications to lightwave technologies
Authors: Matsumoto Takao , Nagase Ryo , Kano Haruo 
Published: July 2007

AbstractIn the fields of single‐mode fiber‐optics, polarization control is an important technique to control undesirable polarization fluctuations. This paper presents a new fiber‐optic fractional wave device which can endlessly and continuously rotate to compensate for polarization fluctuations. A design method is described and factors determining the performance of the device are presented. Characteristics of fabricated devices are described and their applications are introduced. This fiber‐optic fractional device utilizes birefringence induced in a bent fiber. The unique feature is that the fiber is coiled between two rotaing parallel plates with only loose support. This structure makes it possible to achieve a compact endlessly rotatable device. For design comparisons, a figure of merit relating to the characteristics of the bent fiber is proposed. The shape of the fiber bending changes according to the rotation of the device. The effect of this transformation on the characteristics of the device is studied theoretically. Experimental studies are carried out on the effect of coating materials, on fiber durability, and on its characteristics during high‐speed operation. Half‐and quarter‐wave devices for 1.52 μm wavelength are fabricated with losses and birefringence accuracies better than 0.2 dB and ±5%, respectively. A polarization controller realized by utilizing this device is used in a 400 Mb/s optical FSK transmission over 270‐km fiber. It also is used in an LD spectrum width measuring instrument.
Anomalous charging characteristics of Se photoreceptor and its stabilization in high‐speed reversal‐development electrophotography
Authors: Anzai Masayasu 
Published: July 2007

AbstractIn high‐speed electrophotography using the reversal development method, the photoreceptor repeatedly receives positive and negative corona charges. If its period is short (less than about 1 s), the charging voltage varies significantly and the printing is hindered. The charging characteristics in this case have been studied with an Se photoreceptor. The following observations have been obtained: (1) if the negative charge for toner transfer becomes strong, the residual voltage increases more than in the case of the positive charging only; (2) when the negative charging is terminated after positive and negative chargings were repeated, both the charging voltage and the residual voltage increase; (3) this phenomenon is more significant if the temperature is lower. To suppress this anomalous charging phenomenon, a uniform exposure and a recharging process are added before toner transfer so that the operating point of charging is shifted. This method has been confirmed experimentally.
Very high‐speed ROM using bipolar/CMOS technology
Authors: Kurita Koozaburoo , Hotta Takasi , Ueno Masahiro , Hotta Atsuo 
Published: July 2007

AbstractIt is a common practice to realize the internal control of a logic LSI by means of a microprogramming method. A high‐speed operation of this logic LSI requires a highspeed ROM (micro ROM) which stores this microprogram code. This paper proposes a new circuit configuration derived from a combination of bipolar and CMOS technology for a high‐speed micro ROM. In this configuration, the memory cell array is made of MOS transistors while the array periphery consists of a bipolar/CMOS composite circuit in which a high driving capability and a large gm of the bipolar transistor are used so that a high degree of integration and a high speed are attained simultaneously. To confirm the high‐speed characteristic of the proposed circuit, a micro ROM of 2 k words x 64 bits has been fabricated with the 2 μm Hi‐BiCMOS process mixing the bipolar and CMOS structures. The test results of the fabricated device have a minimum read‐out cycle time of 16 ns which is more than twice that of a CMOS circuit having an identical configuration.
Thermomagnetic writing characteristics of holograms on amorphous magnetic films and application to optical matched filtering
Authors: Matsubara Mitsuhito , Saito Katsumi , Kawanishi Kenji 
Published: July 2007

AbstractWriting and reconstruction of holograms on the amorphous magnetic films have been studied and results of matched filtering of imagery by using the hologram filter have been reported. The resolving power of imagery on thin films of GdTbFe and TbFe is 1800 line pairs/mm. The minimum energy Ew for recording holograms on thin films of GdTbFe and TbFe is 100 mJ/cm2 and 50 mJ/cm2, respectively. Ew of TbFeCo and DyFe films is 3000 mJ/cm2 and 20 mJ/cm2, respectively. First order diffraction efficiency of all holograms is of the order of 10−5 ∼ 10−4 percent. Unknown patterns are recorded on the amorphous film as input imagery. Detection of a desired pattern has been made using the spatial matched filtering method that includes a Fourier transform hologram filter. When GdTbFe and TbFe films are used as the filters, correlation output can be detected through the matched filter with 20 dB signal‐to‐noise ratio.
A realization of monolithic variable integrators and their application to automatically tunable high‐frequency active filters
Authors: Nishio Kenichi , Watanabe Yoshiju , Takagi Shigetaka , Yanagisawa Takeshi , Furihata Makoto , Nagata Minoru 
Published: July 2007

AbstractWith the widespread use of home video and other equipment, it is strongly desired to realize a high‐frequency monolithic IC active RC filter. This paper proposes a method of constructing the integrator with voltage‐controlled current source operated by a single 5‐V supply. Even though operated by a single 5‐V supply, the proposed integrator can realize a wide dynamic range due to an elaboration in the output circuit. For a cutoff frequency of 1 MHz, the maximum input voltage for distortionless output voltage is 1.0 VP‐P. By a simple compensation, an excellent high‐frequency characteristic exceeding 2 MHz is obtained. The proposed integrator is of a variable characteristic with differential inputs, and, consequently, an automatically tunable leapfrog‐type filter can be realized. To evaluate the performance of the proposed integrator, a high‐frequency analysis and a computer simulation were made. The integrator was realized as a monolithic IC by the general‐purpose process for home‐use equipment, and the automatically tunable filter was constructed. The experimental result agreed well with the theory, indicating that the whole filter can be realized by a monolithic IC.
Design of fiber holder for optical fiber‐ribbon splice
Authors: Haibara Tadashi , Matsumoto Michito , Miyauchi Mitsuru , Shirai Masataka 
Published: July 2007

AbstractA field‐usable optical fiber‐ribbon holder is proposed. Optical fiber ribbon is fixed by placement between wavy plates. The fiberfixing mechanism is analyzed theoretically and experimentally. Optimum fiber‐holder sizes are also investigated. Using this fiber holder, average and maximum fiber‐end displacement of 3.8 and 15μm are obtained. Lowloss splicing of SM fiber ribbon is confirmed, with average splice loss of 0.05 dB.
Influence of arc discharge types on contact resistance of Ag‐Pd alloys
Authors: Sawa Koichiro , Hasegawa Makoto , Miyachi Kunio 
Published: July 2007

AbstractDifferent types of arc discharge, that is, steady arc, showering arc or no discharge (initial arc), occur at the break of contacts. These arcs are considered to cause not only contact erosion, but also to affect contact resistance. In this paper, the relation between arc‐discharge types and contact resistance is investigated on Ag, Pd and some Ag‐Pd alloy contacts with Pd content of 30, 50 and 70 wt% by using the automatic data acquisition system of newly developed contact resistance. The following can be made clear. Under no discharge and showering arc discharge, contact resistance is always low at any Pd content. However, under steady arc discharge, contact resistances of the contacts with Pd content more than 50 wt% remain low and those of Ag and of AgPd30 become high. From the results of the approximation of distributions of the measured contact resistances with Weibull distribution function, it can be stated that the calculated location parameter RO gives the approximate value of constriction resistance and the scale parameter Rα gives that of film resistance. On the other hand, the observation of contact surfaces reveals the relation between contact resistance and surface conditions. Also, the differences of arc duration or discharge voltage waveforms according to Pd content are recognized. They are considered to influence surface conditions or contact resistance. A physical model that describes these phenomena is proposed.
A new two–dimensional process simulation system HITOP
Authors: Onga Shinji , Kato Kohichi , Taniguchi Kenji 
Published: July 2007

AbstractA new two–dimensional process simulator HITOP is developed which can handle oxidation, diffusion, and ion implementation processes. This simulator can be used for process design of practical scaled MOS basic circuits and has the following characteristics: (i) the region of a size from a few μm to a few tens μm containing multiple MOS devices can be simulated simultaneously; (ii) the variation of the layered film formation during the process can be recognized; (iii) a highly accurate simulation is possible from the viewpoint of physical chemistry modeling and of numerical algorithms; (iv) a bidirectional interface with the shape simulator is contained. It is possible to accept the shape of the etching and deposition processes, continue execution, and return the shape data after the process to the shape simulator. For the benefit of the user, changes of the shape of the junction during the process, situation of the growth of the oxide film and the modification of the top layer are displayed successively so that the basic information for circuit design is provided. The present system can be used with a layout processor and a device simulator.
High stable SAW devices on LST cut of quartz
Authors: Watanabe Takaya , Shimizu Yasutaka 
Published: July 2007

AbstractRecently, we discovered an LST cut which utilizes leaky surface waves for a high stable quartz crystal for SAW devices. This paper examines experimentally the properties of the LST cut. Due to an error for the cut angle for the LST cut, zero temperature coefficients are sometimes not obtained. However, it was shown that such coefficients can be obtained by varying the direction of wave propagation within the cut plane. We examined SAW resonators and oscillators in a 180‐MHz band. We obtained the temperature characteristics of the LST cut in the temperature range from −20 to 80°C with deviations as small as 15 ppm. The obtained Q was as high as 22,500. One of the features of the leaky surface waves is that they have a large value for the propagation velocity. We took advantage of this feature and manufactured SAW filters for 1.8‐ and 4‐GHz bands. Their characteristics are presented in this paper.
Tunable laser using sheet of dye‐doped plastic fibers
Authors: Muto Shinzo , Ando Akitoshi , Yoda Osamu , Hanawa Takayuki , Ito Hiroshi 
Published: July 2007

AbstractThe development of the fiber‐type laser is desired for simple construction of the optical system for several fiber sensor applications. Therefore, in this paper the fabrication of several types of dye‐doped plastic fibers and the laser properties have been studied. When a sheet of dye‐doped fibers was used as an active element and pumped by a pulsed N2 laser, the tunable intense radiation was generated over a wide wavelength region. By using two types of dye‐doped fiber sheets, almost the entire visible region could be covered.
Multiusable printing characteristics of dye transfer sheets
Authors: Taguchi Nobuyoshi , Imai Akihiro , Matsuda Hiromu , Yubakami Keiichi 
Published: July 2007

AbstractDye transfer‐type thermal printing systems have been developed that yield full color prints with excellent tone and color reproducibility. However, utilization efficiency of the recording materials has been poor. Therefore, an experimental evaluation of the materials and the structure of the dye transfer‐type thermally sensitive sheets (dye transfer sheet and color receiving sheet) was performed. It was found that an economical n‐multiple utilization mode printing system, in which the relative speed of the dye transfer sheet to the color receiving sheet is maintained at 1/n (n ≥ 1), can be realized.The dye transfer sheet is composed of a base sheet and a coloring material layer. The base sheet is thermally stabilized by adding a heat resisting and slipping layer on the back of the sheet. The coloring material layer is composed of a dye, adhesive resin and spherical thermal resin spacers. A color developing layer, which contains a heat resisting and slipping UV sensitive color developing resin, is added to the surface of the color receiving base sheet. In the printing experiment, the dye transfer and color receiving sheets were moved by using the surfaces of spacer particles and the coloring material layer.This printing system showed stable operation at n = 12, where the printing density was independent of n. It was found that this method provides a better printing density than the system in which printing is carried out for N times at a constant speed (n = 1).
A method of nonimpact braille printer by electro‐thermosensitive process
Authors: Yonezawa Yoshimichi , Itoh Kazunori , Hattori Hiroshi 
Published: July 2007

AbstractA method of recording braille patterns directly from an electrical signal is studied and its possibility investigated. The method consists in localized electrical conduction in response to the image signal on a sheet which has conductivity and thermal foaming sensitivity. By means of the joule heat generated, small dots with the maximum height of 0.5 mm are formed on the sheet surface to create the equivalent of paper brailles. A thermally sensitive swelling capsule for swelling agents and tin oxides for conductivity are combined in a sheet. The optimum conditions for the composition and the recording method have been found so that a fundamental possibility of generating contact‐resistant brailles is demonstrated which has a low recording noise and a simple recording mechanism.
Development of a high‐reliability flip‐chip packaging reinforced by resin
Authors: Soga Tasao , Nakano Fumio , Fuyama Moriaki 
Published: July 2007

AbstractA high‐reliability chip‐on‐board (COB) technique using the flip‐chip method to mount a driver LSI on a soda‐glass substrate has been developed. By forming a flip‐chip structure in which both the chip and the gap between the chip and the glass substrate are filled with resin, the thermal fatigue life can be one order of magnitude longer than that of a device with an exposed flip‐chip structure. The extension of the device life is due mainly to the relaxation of stress to the device by matching the thermal expansion coefficients of the resin and the solder. Furthermore, using the resin‐filled flip‐chip structure, the breakage of glass at the pedestal section is minimized. The COB package is highly reliable and durable against humidity.
High‐speed and high‐accuracy CMOS LSI for document image signal processor
Authors: Tadauchi Masaharu , Nakashima Keisuke , Nagai Kenji 
Published: July 2007

AbstractA signal processing circuit was created on a one‐chip CMOS LSI in which the document image is read by a line sensor and is converted to digital signals. The present LSI, which corrects various distortions contained in the image signals accurately at a high speed, can handle a high‐speed image signal processing (with 5M picture elements/s maximum) and hence can be applied to an ultra‐high‐speed G4 facsimile. A high‐speed operational amplifier and a high‐speed comparator needed for one‐chip realization are used. Especially, for improvement of accuracy of the CMOS operational amplifier, the automatic offset cancelling system has been developed so that the process of the analog input signal of several hundred millivolts from the sensor can be accomplished. In the present LSI, the CMOS process of 2.5 μm rule is used and the chip size is 6.8 × 7.5 mm.
Examination of picosecond GaAs HEMT photodetector
Authors: Umeda Tokuo , Cho Yoshio 
Published: July 2007

AbstractThe optical response speed of a GaAs MESFET photodetector with an HEMT structure was measured via a correlation method. A high optical response of a full width at half‐maximum (FWHM) 18 ps was obtained. This response speed includes the contribution of the FWHM of the pulse used in the measurement. To estimate the response speed characteristic to the device, the obtained response speed is divided into the portion due to the carrier transit time and that due to the stray capacitance. From the studies of both of these contributions, the contribution by the optical pulse was separated. As a result, the response speed characteristic to the device is estimated to be 12 ps. Also, it is found that the response speed can be reduced to about 8 ps by the reduction of the gate width.
Approximate theory and characteristics of laser doppler velocimeter using self—mixing effect of semiconductor laser diode
Authors: Shinohara Shigenobu , Yoshida Hirofumi , Shimizu Edson Toshiaki , Sumi Masao 
Published: July 2007

AbstractTo explain the experimental characteristics of a laser Doppler velocimeter using the self‐mixing effect of a semiconductor laser diode (LDV) with a rotating disc as a target, a theoretical analysis of a Doppler beat waveform was carried out, and its approximate solution was obtained by using the perturbation method. The theoretical characteristics based on this solution agreed fairly well with the experimental ones. The operating conditions of the LDV required for forming the beat wave into a sawtooth waveform, and the reasons why the sawtooth wave is transformed into a mirror image depending on the sign of the Doppler frequency were found, i.e., the phase angles of the second and third higher harmonics of the beat wave are inverted by the inversion of the direction of rotation. The upper limit of the Doppler frequency and the range of R parameter of the LD were estimated theoretically.