Particulate media composed of very small particles were studied to determine high-density recording performance and thermal stability. Studied media included metal particulate media with mean particle length of 71, 102 and 148 nm, and Ba ferrite particulate media with mean diameter of 22, 28 and 50 nm. Using a loss-term simulation program, taking into account gap-loss, spacing-loss and particle length loss, the recording capability (D20 of 265 kFRPI for MP and 290 kFRPI for Ba ferrite media) was estimated. Thermal stability was evaluated from magnetization time decay measurements. It was found that MP media with large Ku values and 71 nm particles were satisfactorily stable, and the particle volume is still large enough in respect of thermal stability. However, 22-nm Ba ferrite media were less stable, primarily because of small Ku values and particle volume. It was also clarified that positive inter-particle interaction accelerates magnetization time decay, in the presence of a large reverse field.

A novel millimeter-wave slotted waveguide array antenna is developed for automotive radar systems. An antenna structure suitable for mass-production is proposed in this paper. The waveguide is composed of two parts; an upper plate and a bottom plate. It is not necessary to contact each other closely because they are divided at the center of the broad wall of the waveguide where the electric current is small. In addition, grating lobes are suppressed by using a cylindrical cavity around each slot and by controlling the slot arrangement without using dielectric material in the waveguide. We have fabricated the proposed antenna by metal injection molding. The measured antenna efficiency results in 55%, which is quite high in comparison with any other conventional low cost millimeter-wave antenna. This efficiency is almost the same as that of the antenna fabricated by precision metal machining. In this paper, it is confirmed that the proposed antenna could be manufactured with low cost.

The chemical stability of the constituent elements in polycrystalline Sr-Bi-Ta-O thin film with various Bi content prepared by metalorganic chemical vapor deposition (MOCVD) was investigated by X-ray photoelectron spectroscopy (XPS). Moreover, that of the epitaxial films was also investigated to estimate the effect of the grain boundary in polycrystalline films. Therefore, only the Bi element drastically changed from Bi3+ state to Bi0 one by the Ar sputtering. This change increased with increasing the Ta/Bi mole ratio in the film from 0.64 to 1.67. This result was observed not only for the polycrystalline films but also for the epitaxial films, suggesting that this is the grain character not grain boundary one. The stability and the leakage character of the film strongly depend on the constituent of the film.

An experimental report was presented on a high temperature performance of a ZrN barrier in the model system of W/ZrN/poly-Si as a poly-metal gate electrode configuration. The absence of interdiffusion, reaction and/or mixing of the ZrN barrier with adjoining W and poly-Si layers resulted in a successful demonstration of the thermally stable poly-metal gate electrode configuration which tolerated annealing at 850 for 1 h.

Based on the partially-depleted, thin-film SOI/CMOS technology, the influence of reduced junction capacitance on the performance of the elementary gates and large scale gate array chip is reviewed. To further reduce the power consumption, SOI-specific device configurations, in which the body-bias is individually controlled, are effective in lowering the supply voltage and hence the power consumption while keeping the circuit speed. Two attempts are introduced: (1) DTMOS (Dynamic-Threshold MOS)/SOI to achieve ultra low-voltage and yet high-speed operation, and (2) ABB (Active-Body-Bias) MOS to enhance the current drive under the low supply voltage.

In this paper, the distributions of two spectral intensities along the axis of an arc column of the breaking arc are measured by using a combination of a CCD color camera and an additional filter, and arc temperature and metal-vapor quantity are calculated, when copper electrodes interrupt circuits of dc 50 V/3.3 A and 5.0 A. As results; The spectral intensities of excited copper atoms are the strongest near the cathode and become weaker with distance from the cathode in the small number of breaking arcs. The spectral intensities become strong near the anode in the large number of breaking arcs. The average arc temperature in the cross-section of an arc column is high near both the cathode and the anode, and the temperature distribution in the cross-section of the arc column is high at the axis of the arc column, and the arc temperature along the axis of the arc column is high near both the cathode and the anode. The metal-vapor quantity is low near both the cathode and the anode, and it is much at the center of the arc column.

The growth and saturation characteristics of an electromagnetic (EM) wave in a Smith-Purcell free-electron laser (FEL) with a Bragg cavity are investigated in detail with the aid of numerical simulation based upon the fluid model of the electron beam. To analyze the problem, a two-dimensional (2-D) model of the Smith-Purcell FEL is considered. The model consists of a planar relativistic electron beam and a parallel plate metallic waveguide, which has a uniform grating carved on one plate. For confinement and extraction of EM waves, a Bragg cavity is formed by a couple of reflector gratings with proper spatial period and length, which are connected at both ends of the waveguide. The results of numerical simulation show that a compact Smith-Purcell FEL can be realized by using a Bragg cavity composed of metallic gratings.

The Finite-Difference Time-Domain (FDTD) method has been applied to study the scattering characteristics of Fabry-Perot cavities with infinite planar periodic surfaces. Periodic Boundary Conditions (PBC) are used to reduce the analysis to one unit periodic volume. Both dielectric and metallic losses are included in the algorithm using a frequency dependent formalism. This technique is used to study the frequency response of plane parallel Fabry-Perot cavities with square aperture metal mesh mirrors. These cavities are assumed to be illuminated by a normally incident plane wave. After a detailed description of the algorithm, we show theoretically the separate effects of dielectric and metal losses on the transmission coefficient of such cavities. We compare also simulation results to measurements, in the 60 GHz band, of resonant frequencies and Q factors of cavities with various mesh parameters.

Recent years have seen great advances in our understanding and modeling of the coupled diffusion of dopants and defects in silicon during integrated circuit fabrication processes. However, the ever-progressing shrinkage of device dimensions and tolerances leads to new problems and a need for even better models. In this review, we address some of the advances in the understanding of defect-mediated diffusion, focusing on the equations and parameters appropriate for modeling of dopant diffusion in submicron structures.

We have developed a fabrication technique for high-performance high-thermal-stability InP/InGaAs heterojunction bipolar transistors (HBTs) for use in 40-Gb/s ICs. The HBT's T-shaped emitter electrode structure simplifies the fabrication process and enables high controllability of spacing between the emitter and the base electrodes. A highly-C-doped base, grown by gas-source MBE, and a new Pt-based metal system results in a low base resistance. An InP subcollector suppresses thermal runaway of HBTs at high collector current better than a conventional InGaAs subcollector does. Using these techniques, we fabricated a very-high-performance HBT with an extremely high cutoff frequency fT of 235 GHz. The RF measurements show that the collector current at the peak cutoff frequency is inversely proportional to collector thickness. We also fabricated a static 1/2 frequency divider, that can be used for 40-Gb/s optical transmission systems, operating up to 44 GHz. This divider confirmed that the developed HBT is applicable to 40-Gb/s optical transmission ICs.

In a DC 50 V/3.3 A circuit, the spatial distributions of the spectral intensities of breaking arcs near the cathode for silver contacts were measured on the contact surfaces of three different shapes: flat and spherical (1 mm radius and 2 mm radius) and the arc temperature and the metal-vapor quantity were calculated from the spectral intensities. The influence of the contact shape on the arc temperature and the metal-vapor quantity were also examined, as well as the arc tracks on the contact surfaces and the gain and loss of the contacts. Findings show the distributions of spectral intensities are non-symmetrical from the beginning to the extinction of the breaking arc for the flat contact: However, they are symmetrical in the latter half of the breaking in spite of the number of breaking arcs and the shape of contact surface for the spherical contact. The relationship between the area of the arc tracks on the cathode and the shape of contact surface is the same as the relationship between the existent areas of measured spectra and the shape of the contact surface. For the spherical contacts, the arc temperature and the metal-vapor quantity are affected a little by the radius of the curved of contact surface and the number of breaking arcs. However, the longer the arc duration, the higher the metal-vapor quantity is in the latter period of the breaking arc. For the flat contacts, the metal-vapor quantity is lower than those for the spherical contacts. The gain and loss of the contacts are less and the arc duration is shorter for the flat contact than for the spherical contact.

We propose a programming language, Flage, for building software systems which dynamically adapt to changing local situations. In our language, we construct applications by agents; concurrent mobile objects with the metalevel architecture. Metalevel programming facilities realize a self-control of an agent's actions and an autonomous adaptation to changes. We also introduce another kind of program element called field. A field represents a local situation around agents. For example, one field represents a virtual place to get local information in a network environment and another represents a virtual place where agents do cooperative works. If an agent enters a field, it gets programs and shared information in the field. By moving field to field, an agent can change its program composition by itself and it adapts to changing local situations. In this paper, we describe the language specification of Flage, the implementation of the platform for Flage programming and show some program examples.

A correction of the physical optics approximation by accounting for the presence of specific currents concentrated near shadow boundaries on the surface of a convex non-metallic scatterer is analysed by considering a canonical problem of diffraction of a plane electromagnetic wave incident normally to the axis of an infinite circular cylinder with impedance boundary conditions. The analysis focuses on the development of Fock-type asymptotic representations for magnetic field tangent components on the surface of the scatterer. The Fock-type representation of the surface field is uniformly valid within the penumbra region, providing a continuous transition from the geometrical optics formulas on the lit portion of the surface to the creeping waves approximation in the deep shadow region. A new numerical procedure for evaluating Fock-type integrals is proposed that extracts rapidly varying factors and approximates the rest, slowly varying coefficients via interpolation. This allows us to obtain accurate and simple representations for the shadow boundary currents that can be directly inserted into the radiation integral and effectively integrated. We show that accounting for the shadow boundary currents considerably improves the traditional PO analysis of the high-frequency electromagnetic fields scattered from smooth and convex non-metallic obstacles, particularly near the forward scattering direction.

In this study the spectral intensities of a breaking arc were measured near the cathode and the anode between separating Pd contacts in a DC 50 V/5 A circuit, and arc temperature and metal-vapor quantity and density were calculated. Results show the radial distribution of temperature in the cross section of an arc column was constant both near the cathode and the anode from the beginning to the extinction of the breaking arc. Near the cathode the arc temperature in the position of the peak value of spectral intensity rose to about 6000 K at the beginning and remained constant, but near the anode it rose to about 6000 K at the beginning and then decreased towards the extinction of the arc. Both near the cathode and the anode metal-vapor quantity and density rose suddenly at the beginning. Afterwards, they fell near the cathode until extinction. But they became constant approaching extinction near the anode. And the metal-vapor quantity was greater and the density higher near the cathode than near the anode.

We have improved the optical beam induced resistance change (OBIRCH) system so as to detect (1) a current path as small as 10-50 µA from the rear side of a chip, (2) current paths in silicide lines as narrow as 0. 2 µm, (3) high-resistance Ti-depleted polysilicon regions in 0. 2 µm wide silicide lines, and (4) high-resistance amorphous thin layers as thin as a few nanometers at the bottoms of vias. All detections were possible even in observation areas as wide as 5 mm 5 mm. The physical causes of these detections were characterized by focused ion beam and transmission electron microscopy.

An equivalent circuit for designing a coherent power combiner using a quasi-optical resonator has been developed. In the resonator, large numbers of devices (HEMT, HBT, etc. ) are arrayed two dimensionally and mounted on a surface of a metal grooved-mirror. A newly developed equivalent circuit for the resonator has been constructed using a transmission-line model. Experiments performed at Ku-band have shown that oscillation frequencies in a 33 HEMT array oscillator can be predicted with errors of less than 1% by using this equivalent circuit.

We prepared alkoxide solutions to fabricate SrBi2Ta2O9 (SBT) ferroelectric capacitors with IrO2 electrodes. In this process, to minimize excess bismuth, the Sr : Bi : Ta mole ratio was kept at 0. 9 : 2. 1 : 2. 0, i. e. , nearly stoichiometric. Three types of solution - mixed-only (MIX), complexed (COMP), and hydrolyzed (HYD) - were used. The HYD capacitor had low absolute leakage current, 10-7 A/cm2 order, and good saturation properties to 6 V. When voltage was applied to each capacitor at 2 to 6 V, MIX and COMP capacitors showed only partial hysteresis loops due to a high leakage current, reflecting the I-V characteristics. These results are probably due to film density caused by metaloxane network bonding. A fatigue endurance test was conducted using cycling of polarization switching at 6 V using the HYD capacitor with IrO2 electrodes. Slight changes were, however, observed in hysteresis loop configuration, but good hysteresis properties were kept up to 1. 04 1012 cycles. We compared SBT ferroelectric thin films fabricated with Pt electrodes and with IrO2 electrodes. Scarcely any difference due to SBT in the XRD pattern was seen, depending on the substrate material. We found that the use of IrO2 electrodes had the effect of decreasing the crystallization temperature. On Pt and IrO2 electrodes, the two films have surface morphology quite different from that of the rod-like structure wellknown for SBT films prepared using a metal 2-ethylhexanate solution. Their surfaces show a similar morphology with relatively large, closely packed grains. A comparison of the I-V characteristics after reannealing showed that the capacitor with IrO2 electrodes had a higher leakage current than that with Pt electrodes. The leakage current was probably due to the density of the film and interface between the SBT film and electrodes.

Solder joint reliability was studied for hybrid ICs, in which chip components such as FETs, resistors and capacitors were mounted with Sn-Sb solder on an insulated Al substrate and transfer-molded with epoxy resin. Suitable resin selection for molding was also studied. The structure was estimated to have a lifetime of more than ten thousand cycles in the thermal cycling test under the condition of -55/150, for FETs and passive elements. Equivalent plastic strains generated in the soldering layer for the non-molded structure were 4. 6% for the FETs and 3.5% for the passive elements. But, these strains were approximately 1/3 to 1/2 and 1/10 for the molded structure, respectively. This was the main reason for high reliability of the molded structure. Resins with a wide range of thermal expansion coefficient(8-26 ppm/)could be put to practical use, because of the higher reliability of the molded structure. However, a thermal expansion coefficient of about 15 ppm/ was prefered to decrease stress at the interface between the substrate and the molding resin.

The showering arc waveforms generated when contact is being separate have poor reproducibility whose causes are not sufficiently clear. This paper describes that the contact surface conditions which change with the number of contact operations are deeply related to the showering arc waveforms. First, it is experimentally shown that the contacts' surface roughness increases with the number of contact operations, and the growth model of contact surface roughness is proposed based on the change of contact resistance for the number of contact operations. Second, the growth model of molten metal bridge is proposed based on the fact that the showering arc waveforms change with the number of contact operations and the evaluation indexes of showering arc are proposed.

In this paper an algorithm for numerical investigation of the transmission line having a generalized polygonal cross-section and open interface is proposed. Solution of the eigenmode problem is based on the method called the domain product technique, which employs a Mathieu function expansion and provides an efficient technique to the analysis of the structures with multiangular boundaries. An agreement at the obtained numerical results with existing data confirms the applicability of the theoretical analysis given in the paper.