Takamaro Kikkawa

Hiroshima University, Hirosima, Hiroshima, Japan

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Publications (239)205.38 Total impact

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    ABSTRACT: There is no abstract available for this article.
    Applied Physics Letters 07/2015; 107(1):019902. DOI:10.1063/1.4926798 · 3.30 Impact Factor
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    Dan Zhao · Yi Wang · Hongyi Wu · Takamaro Kikkawa
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    ABSTRACT: Modern embedded SoC design uses a rapidly increasing number of processing units for ubiquitous computing, forming the so called embedded many-core SoCs (McSoC). Such McSoC devices allow superior performance gains while side-stepping the power and heat dissipation limitations of clock frequency scaling. The main advantage lies in the exploitation of parallelism, distributively and massively. Consequently, the on-chip communication fabric becomes the performance determinant. To bridge the widening gap between computation requirements and communication efficiency faced by gigascale McSoCs in the upcoming billion-transistor era, a new on-chip communication system, dubbed Wireless Network-on-Chip (WiNoC), has been proposed by using the recently developed RF interconnect technology. With the high data-rate, low power and ultra-short range interconnection provided by UWB technology, the WiNoC design paradigm calls for effective solutions to overhaul the on-chip communication infrastructure of gigascale McSoCs.
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    ABSTRACT: High-performance low-temperature poly-Si thin film transistor (LTPS-TFT) with one-dimensionally elongated long crystal grains have been developed. In the LTPS TFTs, the carrier mobility is enhanced, however the off-leakage current also increase. This is because, grain boundary become longer, and bridge the distance between source and drain, and the grain boundary bridge become a current-leakage path. In this paper, we suggest a novel ozone radical treatment for reducing the off-leakage current.
    2014 21st International Workshop on Active-Matrix Flatpanel Displays and Devices (AM-FPD); 07/2014
  • Shinichi Kubota · Akihiro Toya · Takumi Sugitani · Takamaro Kikkawa
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    ABSTRACT: Interchip data transmission was demonstrated using impulse radio ultrawideband complementary metal-oxide–semiconductor (CMOS) transmitter integrate circuits withon-chip dipole antennas. A differential pseudorandom binary sequence of (2^{7}) data of Gaussian monocycle pulse (GMP) was formed by 65-nm CMOS logic circuits using up- and down-pulses with certain gate delays. The CMOS transmitter generated 5-Gb/s GMP with the center frequency of 10 GHz. To improve transmission gains, an interposer with the high dielectric constant ( (varepsilon _{textrm r} =38)) and optimized thickness was inserted under the CMOS chips as a dielectric slab waveguide. 2-Gb/s GMP signals were transmitted and received in the distance of 10 mm by use of the CMOS on-chip antennas and the high- (kappa ) interposer.
    IEEE Transactions on Components, Packaging, and Manufacturing Technology 07/2014; 4(7):1193-1200. DOI:10.1109/TCPMT.2014.2320497 · 1.18 Impact Factor
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    ABSTRACT: The variability in measurements of complex permittivities of tumor tissues between multiple samples could be attributed to the volume fraction of cancer cells in the excised tumor tissue. By the use of a digital photomicrograph image and hematoxylin-eosin staining, it was found that the malignant tumor tissue was not fully occupied by the cancer cells, but the cells were distributed locally in the stroma cells depending on the growth of cancer. The results showed that the volume fraction of cancer cells in the tumor tissue had a correlation to the measured conductivity and dielectric constant in the frequency range from 1 GHz to 6 GHz. It introduces a method to understand and gauge variability in measurements between different tumors.
    Applied Physics Letters 06/2014; 104(25):253702-253702-5. DOI:10.1063/1.4885087 · 3.30 Impact Factor
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    ABSTRACT: A time-domain reflectometry breast cancer detection system was developed, which was composed of a Gaussian monocycle pulse (GMP) transmitter circuit fabricated by complementary metal oxide semiconductor (CMOS) 65 nm technology and an ultra wide-band (UWB) planar slot antenna array. The center frequency and bandwidth of the antenna were 6 and 9.2 GHz, respectively. The GMP train having the pulse width of 160 ps was generated by the 65 nm CMOS logic circuit with a core area of 0.0017 mm2 and was emitted by the 4 × 4 planar slot antenna array. The fabricated planar 4 × 4 antenna array with the matching layer could resolve the two separate 5 × 5 × 5 mm3 breast tumor phantoms, which were located at the depth of 22 mm with the spacing of 8 mm.
    Japanese Journal of Applied Physics 03/2014; 53(4S):04EL03. DOI:10.7567/JJAP.53.04EL03 · 1.13 Impact Factor
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    ABSTRACT: In this research, a partial amorphization is introduced to form a Nickel suicide ohmic contact for a 4H-SiC bottom electrode. In a conventional Nickel suicide electrode, a carbon agglomeration at the silicide/SiC interface occurs, and constant resistance between Ni silicide and SiC substrate becomes larger. To reduce the contact resistance, a partial amorphization of the surface of SiC substrate was introduced. By this partial amorphization, the space position of the carbon agglomeration is controlled, and contact resistance can be reduced. As a result, with an amorphous 100 nm line pattern, a reliable contact resistance of 1.9x10(-3) Omega cm(2) is realized.
    15th International Conference on Silicon Carbide and Related Materials; 01/2014
  • Li Xu · Xia Xiao · Takamaro Kikkawa
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    ABSTRACT: Ultra-wide band (UWB) microwave imaging is a promising method for the breast cancer detection based on the large contrast of electric parameters between the malignant tumor and its surrounded normal organisms. In this paper, a two-dimensional model of the breast organisms is numerically carried by the finite difference time domain (FDTD) method. The dispersion characteristics of the breast media are taken into account by single pole Debye model to approach the actual properties of the breast organism. In this method, a tumor is assumed in the model with two cases. The standard Capon beamforming (SCB) and doubly constrained robust Capon beamforming (DCRCB) algorithm performed to reconstruct the image is described in detail. The tumor can be detected and localized using the proposed algorithm and the result demonstrates a good stability of DCRCB algorithm.
    Journal of Circuits System and Computers 01/2014; 22(10). DOI:10.1142/S0218126613400276 · 0.25 Impact Factor
  • Seiichi Aritome · Takamaro Kikkawa
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    ABSTRACT: This paper describes scaling limitations and challenges of Self-Aligned STI cell (SA-STI cell) over 2X–0X nm generations for NAND flash memories. The scaling challenges are categorized to (1) narrow Read Window Margin (RWM) problem, (2) structural challenge, and (3) high field (5–10 MV/cm) problem. First, (1) the narrow RWM is investigated by extrapolating physical phenomena of FG–FG coupling interference, Electron Injection Spread (EIS), Back Pattern Dependence (BPD), and Random Telegraph Noise (RTN). The RWM is degraded not only by increasing programmed Vt distribution width, but also by increasing Vt of erase state mainly due to large FG–FG coupling interference. However, RWM is still positive in 1Z nm (10 nm) generation with 60% reduction of FG–FG coupling by air-gap process. For (2) structural challenge, the Control Gate (CG) fabrication margin between Floating Gates (FGs) is becoming much severer beyond 1X nm generation. Very narrow 5 nm FG width/space has to be controlled. For (3) high field problem, high field between CGs (word lines; WLs) is critical during program. By using WL air-gap, high field problem can be mitigated, and 1Y/1Z nm generation seems to be realized. Therefore, the SA-STI cell is expected to be able to scale down to 1Z nm (10 nm) generation, with the air gap of 60% reduced FG–FG coupling interference and an accurate control of FG/CG formation process.
    Solid-State Electronics 04/2013; 82:54–62. DOI:10.1016/j.sse.2013.01.006 · 1.50 Impact Factor
  • Akihiro Toya · Kenta Sogo · Nobuo Sasaki · Takamaro Kikkawa
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    ABSTRACT: For application to an impulse-radio ultra-wideband (IR-UWB) portable breast cancer detection system, a 102.4 GS/s sampling circuit is developed. The high sampling rate is realized by an equivalent-time sampling technique and a low-power multi-clock generation circuit using a phase interpolator. The phase interpolator achieved a minimum phase resolution 9.8 ps. Using the sampling circuit, a tumor phantom buried by a breast phantom was detected. (C) 2013 The Japan Society of Applied Physics
    Japanese Journal of Applied Physics 04/2013; 52(4S):04CE07. DOI:10.7567/JJAP.52.04CE07 · 1.13 Impact Factor
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    ABSTRACT: Advanced dual control gate with surrounding floating gate (DC-SF) cell process and operation schemes are successfully developed for 3-D nand flash memories. To improve performance and reliability of DC-SF cell, new metal control gate last (MCGL) process is developed. The MCGL process can realize a low resistive tungsten (W) metal wordline, a low damage on tunnel oxide/inter-poly dielectric (IPD), and a preferable floating gate (FG) shape. Also, new read and program operation schemes are developed. In the new read operation, the higher and lower Vpass-read are alternately applied to unselected control gates to compensate lowering FG potential to be a pass transistor. In the new program scheme, the optimized Vpass are applied to neighbor WL of selected WL to prevent program disturb and charge loss through IPD. Thus, by using the MCGL process and new read/program schemes, the high performance and reliability of the DC-SF cell can be realized for 3-D nand flash memories.
    IEEE Transactions on Electron Devices 04/2013; 60(4):1327-1333. DOI:10.1109/TED.2013.2247606 · 2.47 Impact Factor
  • Xia Xiao · Xingmeng Shan · Ye Tao · Yuan Sun · Takamaro Kikkawa
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    ABSTRACT: Surface acoustic waves (SAWs) technique is a promising method to determine the mechanical properties of thin low dielectric constant (low-k) dielectrics by matching the experimental dispersion curve with the theoretical dispersion curves. However, it is difficult to calculate the dispersion curves when SAWs propagate along patterned structure. In this paper, finite element method (FEM) is applied to obtain the numerical dispersion results of SAWs propagating on patterned film. Periodic boundary condition and plane-strain model is used to improve the computation speed. Four structures of bulk silicon, single layered low-k film, two layered Cu and SiO2 film, and patterned film, are simulated in this paper. The dispersion curves of single low-k films derived from the FEM simulation agree very well with those calculated by traditional method, which verifies the correct employment of the FEM approach. Dispersion curves of two patterned film structure of Cu and SiO2 with difference metal wire width are obtained. Effective Young's moduli are achieved by fitting the FEM simulated results with those of traditional theoretical calculation through least square error method.
    Journal of Nanoscience and Nanotechnology 02/2013; 13(2):1602-6. DOI:10.1166/jnn.2013.6092 · 1.56 Impact Factor
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    ABSTRACT: A low-k pure silica zeolite film with high-elastic modulus was obtained by hydrothermal synthesis. A two-step hydrothermal synthesis method was used for spin-coated zeolite suspension, followed by nitrogen (N-2) annealing at 400 degrees C. 1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS) silylation treatment and ultraviolet (UV) light (lambda = 172 nm) irradiation was then carried out to promote wear. The effects of the zeolite suspension grain size formed by hydrothermal synthesis on electrical performance and elastic modulus are investigated. Both a high elastic modulus of 5.7 GPa and a low dielectric constant (k = 1.9) were achieved. Moreover, a leakage current density of 10(-9) A/cm(2) at 2 MV/cm was attained.
    01/2013; 2(4):N89-N92. DOI:10.1149/2.018304jss
  • T. Sugitani · S. Kubota · M. Hafiz · A. Toya · T. Kikkawa
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    ABSTRACT: A radar-based breast cancer detection system was developed using a CMOS impulse transmitter circuit and an ultra-wideband (UWB) antenna array. The center frequency and the bandwidth of the antenna were 6 GHz and 12.5 GHz, respectively. A 198 ps Gaussian monocycle pulse (GMP) was generated by the CMOS circuit and emitted by 4x4 planar slot antenna array. The three-dimensional image of a 10 mm x 10 mm tumor phantom buried at the depth of 20 mm in the breast adipose phantom was reconstructed by confocal imaging algorithm.
    Electromagnetic Theory (EMTS), Proceedings of 2013 URSI International Symposium on; 01/2013
  • Takumi Sugitani · Shinichi Kubota · Akihiro Toya · Xia Xiao · Takamaro Kikkawa
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    ABSTRACT: A compact 4 × 4 planar ultrawideband (UWB) antenna array with the total size of 44 × 52.4 mm was developed for radar-based breast cancer detection system. The center frequency and the bandwidth of the antenna were 6 and 12.5 GHz, respectively. The breast phantom materials were developed to fit the characteristics of the measured human breast tissues. A quasi-three-dimensional confocal imaging was performed using the breast phantoms. It was confirmed that the compact 4 × 4 antenna array could detect a 5 × 5 × 5-mm3 tumor phantom in an inhomogeneous structure with a glandular phantom and resolve the two separate tumor phantoms, which were located at the depth of 23 mm with the spacing of 10 mm.
    IEEE Antennas and Wireless Propagation Letters 01/2013; 12:733-736. DOI:10.1109/LAWP.2013.2270933 · 1.58 Impact Factor
  • K. Sogo · A. Toya · T. Kikkawa
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    ABSTRACT: This paper presents a ring voltage-controlledoscillator (ring-VCO)-based sub-sampling phase locked loop(PLL) CMOS circuit with low phase noise and low jitter. A 2.08 GHz PLL is developed by use of 65 nm CMOS technology. The in-band phase noise is -119.1 dBc/Hz at 1 MHz and the output jitter integrated from 1 kHz to 10 MHz is 0.73 ps (rms) with the power consumpition 20.4 mW. The normalized jitter-power product is -229.7 dB.
    Design Automation Conference (ASP-DAC), 2013 18th Asia and South Pacific; 01/2013
  • T. Kikkawa · T. Sugitani
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    ABSTRACT: A 4×4 planar ultra-wideband (UWB) antenna array was developed for radar-based breast cancer detection system in the supine position. The the center frequency and the bandwidth of the antenna were 6 GHz and 12.5 GHz, respectively. The size of an antenna element was 11 mm × 13.1 mm. Confocal imaging was perfomed using breast phantoms whose characteristics were close to those of measured tumors, glandular and adipose tissues. The three-dimensional breast tumor images were reconstructed.
    Antennas and Propagation (EuCAP), 2013 7th European Conference on; 01/2013
  • I.E. Lager · Adrianus T. de Hoop · Takamaro Kikkawa
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    ABSTRACT: Pulse-shape models are presented that furnish the tools for analyzing a number of aspects of the performance of microelectronic circuits. Model pulse shapes are provided and their properties are analyzed in detail. Applications that are covered include the replication of measured pulses that are of relevance for inter- and intra-chip interconnects and, concurrently, examples of passive circuits that generate them. The pulses are appropriate as input to time-domain electromagnetic simulation. They are also instrumental to microelectronic performance prediction protocols and measurement equipment-aspects that are of crucial importance to integrated circuit packaging.
    IEEE Transactions on Components, Packaging, and Manufacturing Technology 11/2012; 2(11):1859-1870. DOI:10.1109/TCPMT.2012.2216266 · 1.18 Impact Factor
  • I.E. Lager · A.T. de Hoop · T. Kikkawa
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    ABSTRACT: The loop-to-loop pulsed electromagnetic field wireless signal transfer is investigated with a view on its application in microelectronic systems and devices. The transmitting loop is excited with a monocycle pulse electric current. Closed-form expressions are derived for the emitted magnetic field and for the open-circuit voltage of the receiving loop in dependence on the mutual orientation of the loops and the parameters of the feeding pulse. Numerical results are given for some configurations that are representative for microelectronic wireless signal transfer. They are indicative for the potentialities of the pulsed-field wireless signal transfer concerning the received signal characteristics and the compliance with regulatory specifications on Electro Magnetic Emission.
    Antennas and Propagation (EUCAP), 2012 6th European Conference on; 01/2012
  • T. Kikkawa · A. Toya · S. Kubota · M. Hafiz · A. Azhari · N. Sasaki
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    ABSTRACT: Impulse radio ultra-wide-band complementary metal oxide semiconductor (IR-UWB-CMOS) integrated circuits have been developed for breast cancer detection. The circuits consist of Gaussian monocycle pulse (GMP) generator and transmitter, low noise amplifier (LNA), equivalent time sampling circuits and analog to digital converter. The GMP with the center frequency of 6 GHz was digitally generated and transmitted by use of off-chip UWB antennas. The received signals were digitized by equivalent time sampling technique and were transformed to the two-dimensional pixels by confocal imaging algorism.
    Antennas and Propagation (EUCAP), 2012 6th European Conference on; 01/2012

Publication Stats

1k Citations
205.38 Total Impact Points


  • 1998–2015
    • Hiroshima University
      • Research Institute for Nanodevices and Bio Systems
      Hirosima, Hiroshima, Japan
  • 2011
    • University of Louisiana at Lafayette
      • Computer Studies, Advanced
      Lafayette, Louisiana, United States
  • 1989–2008
    • NEC Corporation
      Edo, Tōkyō, Japan
  • 2007
    • Tianjin University
      • Department of Electronic Information Engineering
      T’ien-ching-shih, Tianjin Shi, China
  • 2001–2007
    • National Institute of Advanced Industrial Science and Technology
      Tsukuba, Ibaraki, Japan
  • 2006
    • Advance Institute of Science and Technology
      Dehra, Uttarakhand, India
  • 2005
    • Bangladesh University of Engineering and Technology
      • Department of Electrical and Electronic Engineering
      Mujib City, Dhaka, Bangladesh
  • 2004
    • Tsukuba Memorial Hospital
      Tsukuba, Ibaraki, Japan