The search functionality is under construction.
The search functionality is under construction.

Keyword Search Result

[Keyword] metal(132hit)

21-40hit(132hit)

  • Reflection and Transmission Characteristics of Laminated Structures Consisting a Dipole Array Sheet and a Wire Grid and Dielectric Layer

    Shinichiro YAMAMOTO  Kenichi HATAKEYAMA  Takanori TSUTAOKA  

     
    PAPER

      Vol:
    E98-B No:7
      Page(s):
    1235-1241

    This paper proposes reflection and transmission control panels using artificially designed materials. As the artificially designed material, finite- and infinite-length metal wire array sheets are used here. Laminated structures consisting of the metal wire array sheets and dielectric material are proposed. Reflection and transmission characteristics of these structures can be controlled by changing the metal wire parameters such as wire length, spacing gaps between the wires, and the dielectric material's thickness and relative permittivity. The reflection and transmission characteristics of the laminated structures are evaluated by measurements in free space and by transmission line theory.

  • Resistance-Switching Characteristics of Si-rich Oxide Evaluated by Using Ni Nanodots as Electrodes in Conductive AFM Measurements

    Akio OHTA  Chong LIU  Takashi ARAI  Daichi TAKEUCHI  Hai ZHANG  Katsunori MAKIHARA  Seiichi MIYAZAKI  

     
    PAPER

      Vol:
    E98-C No:5
      Page(s):
    406-410

    Ni nanodots (NDs) used as nano-scale top electrodes were formed on a 10-nm-thick Si-rich oxide (SiO$_{mathrm{x}}$)/Ni bottom electrode by exposing a 2-nm-thick Ni layer to remote H$_{2}$-plasma (H$_{2}$-RP) without external heating, and the resistance-switching behaviors of SiO$_{mathrm{x}}$ were investigated from current-voltage ( extit{I--V}) curves. Atomic force microscope (AFM) analyses confirmed the formation of electrically isolated Ni NDs as a result of surface migration and agglomeration of Ni atoms promoted by the surface recombination of H radicals. From local extit{I--V} measurements performed by contacting a single Ni ND as a top electrode with a Rh coated Si cantilever, a distinct uni-polar type resistance switching behavior was observed repeatedly despite an average contact area between the Ni ND and the SiO$_{mathrm{x}}$ as small as $sim$ 1.9 $ imes$ 10$^{-12}$cm$^{2}$. This local extit{I--V} measurement technique is quite a simple method to evaluate the size scalability of switching properties.

  • Analysis on Non-Ideal Nonlinear Characteristics of Graphene-Based Three-Branch Nano-Junction Device

    Xiang YIN  Masaki SATO  Seiya KASAI  

     
    PAPER

      Vol:
    E98-C No:5
      Page(s):
    434-438

    We investigate the origin of non-ideal transfer characteristics in graphene-based three-branch nano-junction (TBJ) devices. Fabricated graphene TBJs often show asymmetric nonlinear voltage transfer characteristic, although symmetric one should appear ideally. A simple model considering the contact resistances in two input electrodes is deduced and it suggests that the non-ideal characteristic arises from inequality of the metal-graphene contact resistances in the inputs. We fabricate a graphene TBJ device with electrically equal contacts by optimizing the contact formation process and almost ideal nonlinear characteristic was successfully demonstrated.

  • Simulation Study of Short-Channel Effect in MOSFET with Two-Dimensional Materials Channel

    Naoki HARADA  Shintaro SATO  Naoki YOKOYAMA  

     
    BRIEF PAPER-Semiconductor Materials and Devices

      Vol:
    E98-C No:3
      Page(s):
    283-286

    The short-channel effect (SCE) in a MOSFET with an atomically thin MoS$_{2}$ channel was studied using a TCAD simulator. We derived the surface potential roll-up, drain-induced barrier lowering (DIBL), threshold voltage, and subthreshold swing (SS) as indexes of the SCE and analyzed their dependency on the channel thickness (number of atomic layers) and channel length. The minimum scalable channel length for a one-atomic-layer-thick MoS$_{2}$ MOSFET was determined from the threshold voltage roll-off to be 7.6,nm. The one-layer-thick device showed a small DIBL of 87,mV/V at a 20 nm gate length. By using high-k gate insulator, an SS lower than 70,mV/dec is achievable in sub-10-nm-scale devices.

  • Surface Potential Measurement of Organic Multi-layered Films on Electrodes by Kelvin Probe Force Microscopy

    Nobuo SATOH  Shigetaka KATORI  Kei KOBAYASHI  Kazumi MATSUSHIGE  Hirofumi YAMADA  

     
    PAPER

      Vol:
    E98-C No:2
      Page(s):
    91-97

    We have investigated both the film thickness and surface potential of organic semiconductors deposited on two kinds of electrodes by the simultaneous observation with the dynamic force microscopy (DFM)/Kelvin-probe force microscope (KFM). To clarify the interfacial properties of organic semiconductor, we fabricated samples that imitated the organic light emitting diode (OLED) structure by depositing bis [$N,N '$-(1-naphthyl)-$N,N '$-phenyl] benzidine ($alpha$-NPD) and tris (8-hydroxyquinolinato) aluminum (Alq$_{3}$), respectively, on indium-tin-oxide (ITO) as anode and aluminum (Al) as cathode by the vacuum evaporation deposition using intersecting metal shadow masks. This deposition technique enables us to fabricate four different areas in the same substrate. The crossover area of the deposited thin films were measured by the DFM/KFM, the energy band diagrams were depicted and we considered that the charge behavior of the organic semiconductor depended on the material and the structure.

  • Micromagnetic Study of Influence of Gd Content on Current-Induced Domain Wall Motion in a Ferrimagnetic Nanowire

    Jo KAJITANI  Takashi KOMINE  Ryuji SUGITA  

     
    PAPER

      Vol:
    E96-C No:12
      Page(s):
    1515-1519

    In this study, the influence of Gd composition on current-induced domain wall motion in a Gd-Co ferrimagnetic nanowire was theoretically investigated with taking into account of composition dependence of magnetic properties. As a result, the intrinsic critical density to move domain wall significantly reduces near the compensation composition, which is achieved to be less than 105A/cm2. Moreover, the intrinsic critical current density also significantly reduces near a certain Gd composition where the domain wall energies of Bloch and Néel walls are almost the same.

  • Fretting Characteristics of Dissimilar Metal Contacts

    Tetsuya ITO  Takuya YAMANAKA  Yasuhiro HATTORI  

     
    PAPER

      Vol:
    E96-C No:9
      Page(s):
    1104-1109

    The authors previously conducted the observation of microstructures and three-dimensional SEM on fretting wear phenomena at tin-plated contacts. In this study, we report the fretting characteristics of dissimilar metal contacts by studying the relation between the contact resistance behaviors and micro structural changes of gold and tin-plated fretting contacts, through surface SEM observations and cross sectional SEM and AES analysis.

  • Contact Resistance Distribution on Anode Surfaces Eroded by Break Arcs in a DC48V Resistive Circuit

    Junya SEKIKAWA  Katsuyoshi MIYAJI  

     
    PAPER

      Vol:
    E96-C No:9
      Page(s):
    1142-1147

    Break arcs are generated in a DC48V resistive circuit. The circuit current is varied from 1A to 6A. The contact resistance distribution on the anode surfaces eroded by break arcs is investigated. The following results are shown. When the current is 2A, 3A and 6A, the contact resistance at the center region of the anode surface is higher than that around the center region. The contact resistance around the center region decreases with the decrease of the circuit current. When the current is 1A, the contact resistance is very low at all positions on the contact surface. The lower contact resistance may be caused by the occurrence of the short arc that is extinguished in the metallic phase arc.

  • Channel Capacity Improvement in Near-Field MIMO System Using Metal Wires

    Dalin ZHANG  Toshikazu HORI  Mitoshi FUJIMOTO  

     
    PAPER-Antennas and Propagation

      Vol:
    E96-B No:5
      Page(s):
    1141-1148

    This paper clarifies the effects of metal wires placed around a Multiple-Input-Multiple-Output (MIMO) array with the goal of improving the channel capacity in near-field MIMO systems. Tests are performed on dual-dipole arrays with metal wires placed parallel to the dipoles. If the antenna elements have an appropriate half-power beamwidth (HPBW), there is a clear improvement in the channel capacity of the dual-dipole array. The metal wires are used to increase the multipath richness and the locations of the wires significantly impact the channel capacity. A significant increase in the channel capacity is observed even if only one metal wire is placed in the proper location. We verified the generality of applying a metal wire to improve the channel capacity and that the improvement in the channel capacity is approximately proportional to the number of metal wires.

  • Development and Evaluation of a Wide Range Impulse Current Generator for Surge Arrester Testing

    Kuo-Hsiung TSENG  Ching-Lin HUANG  Pei-Yu CHENG  Zih-Ciao WEI  

     
    PAPER-Measurement Technology

      Vol:
    E96-A No:3
      Page(s):
    713-720

    This paper is focused on discussing a low-voltage system for lightning, and in particular the testing equipment of surge arresters. Only by demonstrating the performance and applicability of arresters can we seek the most feasible and economic low-voltage solutions. After performing repeated experiments with the same testing samples, using different testing equipment, we compare the different test results in order to select the most suitable and applicable testing equipment. In addition, the basis of a surge current parameter design theory is confirmed and verified through the test results using a simple and compact Impulse Current Generator to test a wide range of samples. By performing the actual analyzes and experiments, we can understand deeply how R, L, and C affect surge current, current wave, and current wave time. The ideal testing equipment standards have been set as follows: (1) Test Voltage up to 20 kV; (2) Expand current range from 1.5 kA to 46.5 kA, with resolution 1.5 kA; and (3) Simple operational procedures.

  • A CMOS SRAM Test Cell Design Using Selectively Metal-Covered Transistors for a Laser Irradiation Failure Analysis

    Hiroshi HATANO  

     
    BRIEF PAPER-Electronic Circuits

      Vol:
    E95-C No:11
      Page(s):
    1827-1829

    A laser irradiation experiment for photocurrent induced failure investigations was described. In order to focus a laser beam on a desired transistor, novel test circuit structures using selectively metal-covered transistors were proposed. Photocurrent induced upset failures were successfully observed in fabricated CMOS SRAM test cells. Results were discussed with SPICE simulations.

  • Metal-Cavity Nanolasers and NanoLEDs Open Access

    Shun Lien CHUANG  Chi-Yu NI  Chien-Yao LU  Akira MATSUDAIRA  

     
    INVITED PAPER

      Vol:
    E95-C No:7
      Page(s):
    1235-1243

    We present the theory and experiment of metal-cavity nanolasers and nanoLEDs flip-chip bonded to silicon under electrical injection at room temperature. We first review the recent progress on micro- and nanolasers. We then present the design rule and our theoretical model. We show the experimental results of our metal-cavity surface-emitting microlasers and compare with our theoretical results showing an excellent agreement. We found the important contributions of the nonradiative recombination currents including Auger recombination, surface recombination, and leakage currents. Finally, experimental demonstration of electrical injection nanoLEDs toward subwavelength nanoscale lasers is reported.

  • Switching Characteristics in Variable-Index Arrayed Waveguides Using Thin-Film Heater

    Satoshi YANAGI  Yosuke MURAKAMI  Yuki YAMAZAKI  Kazuhiko SHIMOMURA  

     
    PAPER

      Vol:
    E95-C No:7
      Page(s):
    1265-1271

    We have demonstrated switching characteristics in a wavelength switch based on multiple GaInAs/InP quantum wells. It consisted of straight arrayed waveguides with a linearly varying refractive index distribution. The refractive index can be changed via the thermo-optic (TO) effect. Using a Ti/Au thin-film heater to generate the TO effect, we realized four-port switching at four demultiplexed wavelengths. In addition, by changing the structure of the heater from rectangular to triangular, the power consumption for four-port switching was reduced by half.

  • Effect of Axial and Transverse Magnetic Fields on the Arc Duration and Material Transfer

    Guofu ZHAI  Xinglei CUI  Xue ZHOU  

     
    PAPER-Electromechanical Devices and Components

      Vol:
    E95-C No:3
      Page(s):
    395-400

    Axial and transverse magnetic fields are widely used in many kinds of switches to decrease the arc erosion. In this paper, the influence of these two kinds of magnetic fields on the arc phase transition was studied particularly for AgSnO2 contacts breaking a 28 V/25 A circuit. The experiments were carried out under resistive and inductive loads in an atmospheric environment. The relationships between flux densities ranging from 0 to 200 mT and the arc duration were obtained. It was found that the transverse magnetic field was more efficient in balancing the arc phases and decreasing the arc erosion. The results can be used to guide the design of arc extinguishment systems in DC high power relays.

  • Broadband Light Source Based on Four-Color Self-Assembled InAs Quantum Dot Ensembles Monolithically Grown in Selective Areas

    Nobuhiko OZAKI  Koichi TAKEUCHI  Shunsuke OHKOUCHI  Naoki IKEDA  Yoshimasa SUGIMOTO  Kiyoshi ASAKAWA  Richard A. HOGG  

     
    BRIEF PAPER

      Vol:
    E95-C No:2
      Page(s):
    247-250

    We developed advanced techniques for the growth of self-assembled quantum dots (QDs) for fabricating a broadband light source that can be applied to optical coherence tomography (OCT). Four QD ensembles and strain reducing layers (SRLs) were grown in selective areas on a wafer by the use of a 90° rotational metal mask. The SRL thickness was varied to achieve appropriate shifts in the peak wavelength of the QD emission spectrum of up to 120 nm. The four-color QD ensembles were expected to have a broad bandwidth of more than 160 nm due to the combination of excited state emissions when introduced in a current-induced broadband light source such as a superluminescent diode (SLD). Furthermore, a desired shape of the SLD spectrum can be obtained by controlling the injection current applied to each QD ensemble. The broadband and spectrum shape controlled light source is promising for high-resolution and low-noise OCT systems.

  • Electrical and Structural Properties of Metal-Oxide-Semiconductor (MOS) Devices with Pt/Ta2O5 Gate Stacks

    Hoon-Ki LEE  S.V. Jagadeesh CHANDRA  Kyu-Hwan SHIM  Jong-Won YOON  Chel-Jong CHOI  

     
    BRIEF PAPER

      Vol:
    E94-C No:5
      Page(s):
    846-849

    We fabricated metal-oxide-semiconductor (MOS) devices with Pt/Ta2O5 gate stacks and investigated their electrical and structural properties. As increasing RF magnetron sputter-deposition time of Ta2O5 film, the values of equivalent oxide thickness (EOT) and flat band voltage (VFB) increase whilst the density of interfacial trap (Dit) gradually decreases. The effective metal work function (Φm,eff) of Pt metal gate, extracted from the relations of EOT versus VFB are calculated to be ∼5.29 eV, implying that Fermi-level pinning in Ta2O5 gate dielectric is insignificant.

  • Temperature Dependency of Driving Current in High-k/Metal Gate MOSFET and Its Influence on CMOS Inverter Circuit

    Takeshi SASAKI  Takuya IMAMOTO  Tetsuo ENDOH  

     
    PAPER

      Vol:
    E94-C No:5
      Page(s):
    751-759

    As the integration density and capacitance of semiconductor devices have increased, high-dielectric (High-k) materials have attracted considerable attention. We investigated the dependence of threshold voltage (Vth) characteristics of the High-k/Metal Gate MOSFET fabricated with 65 nm CMOS process on the temperature, in comparison to conventional SiON/Poly-Si Gate MOSFET. Two aspects including the Fermi level and the channel mobility in MOSFET are discussed in details. Furthermore, the influence of threshold voltage characteristics of the High-k/Metal Gate MOSFET on the logic threshold voltage (Vth-inv) of CMOS inverter is reported in this paper.

  • A Reflectance Model for Metallic Paints Using a Two-Layer Structure Surface with Microfacet Distributions

    Gang Yeon KIM  Kwan H. LEE  

     
    PAPER-Image Recognition, Computer Vision

      Vol:
    E93-D No:11
      Page(s):
    3076-3087

    We present a new method that can represent the reflectance of metallic paints accurately using a two-layer reflectance model with sampled microfacet distribution functions. We model the structure of metallic paints simplified by two layers: a binder surface that follows a microfacet distribution and a sub-layer that also follows a facet distribution. In the sub-layer, the diffuse and the specular reflectance represent color pigments and metallic flakes respectively. We use an iterative method based on the principle of Gauss-Seidel relaxation that stably fits the measured data to our highly non-linear model. We optimize the model by handling the microfacet distribution terms as a piecewise linear non-parametric form in order to increase its degree of freedom. The proposed model is validated by applying it to various metallic paints. The results show that our model has better fitting performance compared to the models used in other studies. Our model provides better accuracy due to the non-parametric terms employed in the model, and also gives efficiency in analyzing the characteristics of metallic paints by the analytical form embedded in the model. The non-parametric terms for the microfacet distribution in our model require densely measured data but not for the entire BRDF(bidirectional reflectance distribution function) domain, so that our method can reduce the burden of data acquisition during measurement. Especially, it becomes efficient for a system that uses a curved-sample based measurement system which allows us to obtain dense data in microfacet domain by a single measurement.

  • Design of a Partially-Corporate Feed Double-Layer Slotted Waveguide Array Antenna in 39 GHz Band and Fabrication by Diffusion Bonding of Laminated Thin Metal Plates

    Miao ZHANG  Jiro HIROKAWA  Makoto ANDO  

     
    PAPER-Antennas

      Vol:
    E93-B No:10
      Page(s):
    2538-2544

    Introducing diffusion bonding of laminated thin metal plates to the fabrication of slotted waveguide arrays enlightens the high potential and the feasibility of multi-layer antennas with high-performance. It is a promising process with low cost even for a double-layer antenna, because the number of etching patterns for thin metal plates is only five. In this paper, a double-layer antenna for broadband characteristics is designed in 39 GHz band as demonstration. A 20 20-element antenna is composed of 2 2 sub-arrays by installing a partially-corporate feed circuit in the bottom layer underneath radiating waveguides in the top layer. The five-element sub-arrays in both the feeding and radiating parts are designed first. A new structure for the last slot coupler with shortened termination is also proposed to avoid an extra slot-free region when assembling the neighbor sub-arrays. As the simulation results by HFSS, the maximum gain of 34.55 dBi with the antenna efficiency of 85.5% is estimated at 38.5 GHz. The test antenna is fabricated by the diffusion bonding of thin copper plates. As the measurement results, a very high aperture efficiency of 83.2% with the directivity of 34.5 dBi is realized at the center frequency of 38.75 GHz, where the antenna gain of 34.4 dBi with the high antenna efficiency of 81.4% is achieved. The bandwidth of 5.0% defined as 1 dB down from the maximum gain is achieved.

  • Opening Electrical Contacts: The Transition from the Molten Metal Bridge to the Electric Arc Open Access

    Paul G. SLADE  

     
    INVITED PAPER

      Vol:
    E93-C No:9
      Page(s):
    1380-1386

    This paper presents a comprehensive explanation of the formation of the electric arc between opening contacts in a current carrying electric circuit. As the contacts begin to open a molten metal bridge forms between them. The rupture of this bridge and the initial formation of the electric arc are studied in both atmospheric air and vacuum using experiments to determine the direction of metal transfer between the contacts as a function of time after the rupture of the molten metal bridge. High speed streak photography is also used to show the rupture of the molten metal bridge and the initial formation of the electric arc. Analysis of these data show that a very high-pressure, high-temperature metal vapor zone exists between the contacts after the rupture of the molten metal bridge. Under this condition a pseudo-arc forms where current is carried by metal ions and an anomalous, high net transfer of metal to the cathodic contact occurs. The pressure in this region decreases rapidly and there is a transition to the usual electric arc, which still operates in the metal vapor. In this arc the current is now mostly carried by electrons. The data shows that there is still a net transfer of metal to the cathode, but now its volume is a function of the arcing time.

21-40hit(132hit)