T. Ono

Tohoku University, Sendai-shi, Miyagi-ken, Japan

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Publications (76)28.86 Total impact

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    ABSTRACT: An optically controllable photocathode array made of Si with carbon nanotubes (CNTs) has been developed. The CNTs were grown on apex of Si tips with pn junction. The Si tips were formed on a Si membrane. Laser intensity dependence on IV characteristics of this photo cathode array has been measured. Electron emission can be switched on by laser irradiation, and the emission current also can be controlled by intensity of irradiated laser. Optical switching of electron emission had been successfully demonstrated.
    Micro Electro Mechanical Systems (MEMS), 2013 IEEE 26th International Conference on; 01/2013
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    ABSTRACT: A thin film of boron nitride is synthesized on a Si substrate using BCl3 and NH3 as source gases, by thermal chemical vapor deposition. Cubic boron nitride (c-BN) is preferentially synthesized using a Fe thin film. The c-BN film exhibits negative electron affinity. A gated silicon field emitter array coated with a c-BN thin film for multi electron beam lithography is developed. Large emission current can be achieved in BN-coated Si emitter.
    Vacuum Nanoelectronics Conference (IVNC), 2013 26th International; 01/2013
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    ABSTRACT: In this paper, silicon resonators were hermetically packaged on basis of anodic bonding of Si and LTCC (Low Temperature Co-fired ceramic) substrates. This research aims at developing the integration technology of the resonator on LSI (Large Scale Integration) for application of a timing device. The structures of the resonators were transferred onto the LTCC substrate using the anodic bonding of silicon and LTCC for electrical interconnections. Then the resonator structures were packaged hermetically by the second anodic bonding of silicon and Tempax glass for encapsulation. The device can be directly bonded to LSI.
    Micro Electro Mechanical Systems (MEMS), 2013 IEEE 26th International Conference on; 01/2013
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    ABSTRACT: A miniature Fourier transform infrared spectrometer (FTIR) is designed and fabricated. The spectrometer consists of an electrostatically-driven Si wishbone interferometer (size: 8 × 8 mm2), Si capacitive displacement sensor, light source with an aperture, and detector. Three-dimensional Si micromirror is assembled on the interferometer. The miniature FTIR operates in mid-infrared range, and multi gas detection including CO2 and water has been demonstrated using this miniaturized FTIR.
    Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS & EUROSENSORS XXVII), 2013 Transducers & Eurosensors XXVII: The 17th International Conference on; 01/2013
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    ABSTRACT: A moving-magnet-type 2-axis MEMS scanner with a rotation angle detector has been developed. The fabricated MEMS scanner demonstrated a raster scan and 2-axis rotation angles detection with one Hall sensor.
    Optical MEMS and Nanophotonics (OMN), 2011 International Conference on; 01/2011
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    ABSTRACT: This Letter reports on the deposition of a conductivity-switching polyimide film as a recording medium formed by molecular layer deposition (MLD). It also reports on the electrical modification on it using a scanning probe microscope (SPM). The polyimide film is uniformly deposited on an Au surface by MLD. As the result of the electrical modification, highly conductive dots pattern with a narrow pitch of approximately 50 nm is successfully defined by applying pulsed voltages. The current ratio of the electrical modified area to unmodified area reached 300 at least.
    Micro & Nano Letters 11/2010; · 0.85 Impact Factor
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    ABSTRACT: A time-of-flight scanning force microscope (SFM) probe with an ability to switch the measurement mode using the electrostatically switching mechanism is designed, fabricated and demonstrated the performance of it. In order to achieve surface observation and chemical analysis simultaneously for imaging the chemical property of a material surface, this probe can switch the positions of the cantilever between SFM mode and time-of-flight mass analysis (TOF-MA) mode by integrating a couple of electrostatic actuator with curved electrode. This mechanism will be applied to pick up an atom or molecule under SFM mode, then emits them to TOF mass analyzer using field evaporation for analyzing its mass in TOF-MA mode. To switch the cantilever position at TOF-MA mode, the fabricated probe generated the 255 mum of maximum displacement at the end of cantilever at an actuation voltage of 180 V. The cantilever is attracted with the electrode according to the curved shape using electrostatically pull-in effect. The front edge of the cantilever was aligned in front of integrated extraction electrode for emitting chemical species. In SFM mode, the cantilever was also attracted to another electrode. The fundamental resonant frequency of the cantilever is increased from 1.8 kHz to 6.8 kHz before and after actuation. A calculated spring constant is changed from 0.05 N/m to 0.34 N/m.
    Micro Electro Mechanical Systems, 2009. MEMS 2009. IEEE 22nd International Conference on; 03/2009
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    ABSTRACT: This paper presents the design, fabrication and characterization method of piezoresistive nanocantilevers for ultra-sensitive force detection application. A shallow boron-doped layer as thin as 40 nm is achieved using spin-on diffusion. The piezoresistive nanocantilevers are patterned by electron beam (EB) lithography and fast atom beam (FAB) etching. The resonance response of the nanocantilevers is characterized by both optical readout using a laser Doppler vibrometer and piezoresistive self-detection. A soft spring effect is detected in the nanocantilevers.
    Measurement Science and Technology 07/2008; 19(8):084011. · 1.44 Impact Factor
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    ABSTRACT: In this paper, we have proposed, fabricated and characterized a parallel electron beam micro-column with single-stranded carbon nanotube (CNT) filed emitters. The integrated micro-column consists of a self-aligned CNT field emitter array (FEA), and a multi-layered electrostatic Si focusing lens array. In our design, the emitters, gate and electrostatic lens array are electrically isolated, and each source can be controlled individually. Electron emission performance of the fabricated CNT/Si emitter was characterized. The best turn-on fields, defined as the field required to generate an emission current of 1 nA, were approximately 6 V. When applying a gate voltage of 100 V, a 110 nA anode current is measured. It is seen that CNT/Si emitter showed low threshold voltage; however, the emission current fluctuation was high during high voltage operation.
    Micro Electro Mechanical Systems, 2008. MEMS 2008. IEEE 21st International Conference on; 02/2008
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    ABSTRACT: In this paper, a novel probe with an integrated radio frequency single-electron transistor (rf-SET) for magnetic resonance force microscopy operated at low temperatures is proposed and fabricated. By using the charge sensitivity of the rf-SET, the displacement of a cantilever can be detected from the capacitance variation between the quantum island and the gate formed on the cantilever with high sensitivity. The rf-SET using a Cr thin film isolated with tunneling junction of a thin silicon dioxide film was fabricated on the basis of electron beam lithography and self-aligned island formation.
    Solid-State Sensors, Actuators and Microsystems Conference, 2007. TRANSDUCERS 2007. International; 07/2007
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    ABSTRACT: This paper reports on the development and evaluation of various multi-probes consisted of silicon cantilevers with different types of tips made of platinum, ruthenium, chromium and diamond for probe-based ultra-high-density ferroelectric data storages beyond 1 Tbit/inch . The metal probes can write and read the data bits on a medium with contact operation. We performed wear tests on the various tips of probe against a ferroelectric medium. Obvious wear of the tips cannot be observed except for the platinum-tip. Spontaneously polarized domain distribution of LiTaO<sub>3</sub> was measured by means of scanning nonlinear dielectric microscopy using ruthenium tip probe.
    Solid-State Sensors, Actuators and Microsystems Conference, 2007. TRANSDUCERS 2007. International; 07/2007
  • Wonje Cho, T. Ono, M. Esashi
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    ABSTRACT: A miniature electron source with small electron windows for use in atmospheric environment has been developed. Electron windows made of 50-nm thick silicon with sizes of 250 nm diameter and 1.5 mum square are fabricated at the bottom of an aperture. Electrons from carbon nanocoils as emitters can be emitted by field emission and transmitted into atmospheric pressure via submicron electron window. The transmittance via the electron window and current density are evaluated to be 4% and 90 pA/mum<sup>2</sup> , respectively. At the acceleration voltage of 10 kV, electrons penetrated the electron window, ant its pattern was transferred on resist.
    Solid-State Sensors, Actuators and Microsystems Conference, 2007. TRANSDUCERS 2007. International; 07/2007
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    ABSTRACT: Integration of metals and semiconductors having three- or sixfold symmetry on device-oriented [i.e., (001)] silicon wafers, which have fourfold symmetry, has been a long-standing challenge. The authors demonstrate that, by using symmetry-converted (111) silicon on insulator, wurtzite-structure gallium nitride, which has threefold symmetry, can be integrated with Si(001). The stability of the symmetry-converted Si(111) layer makes this technique appealing to the commercial integration of wide-ranging important materials onto Si(001) base wafers. c 2007 American Institute of Physics.
    Applied Physics Letters 06/2007; · 3.52 Impact Factor
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    ABSTRACT: We report the fabrication of a solenoidal microcoil mould structure based on reactive ion etching (RIE) of 100 mum thick borosilicate glass wafers. For magnetic resonance imaging (MRI), glass has superior properties compared to silicon, e.g. the lower dielectric constant and transparency. Double-side polished substrates are pre-etched in a two step process, and then anodically bonded together to achieve a hollow structure inside the coil to serve as a sample container. Two additional etch steps that are each performed on the top and bottom surfaces of the bonded wafers complete the solenoidal coil mould structure.
    Micro Electro Mechanical Systems, 2007. MEMS. IEEE 20th International Conference on; 02/2007
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    ABSTRACT: The design, fabrication and characterization of an integrated Schottky emitter array are presented and demonstrated. The integrated emitter array consists of boron-doped diamond heaters with a diamond tip, Si micro gate array and Si focusing lens array. The diamond film is selectively deposited using electrophoresis of diamond seed particles and a hot filament chemical vapor deposition (HF-CVD) technique. The emitters, gate and lens array are electrically isolated from each other on a Pyrex glass substrate. When heating the diamond emitter at a voltage of 2.8 V, an emission current of 490 nA has been observed at an electric field of 0.36 V/ mum. The emission current was found to be stable with a fluctuation of 2% per hr. By fitting the measure data with Schottky emission model, the temperature at the emitter was calculated to be 1680degC.
    Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS) 01/2007;
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    ABSTRACT: In this paper, we present a photothermal transducer consisted of an ultrathin Au/Si bimetal cantilever as a resonator with a total thickness of 45 nm and quality factor of -12000. Due to the high quality factor and small size, this transducer is sensitive to photothermal effect and its thermal response frequency can be up to 140 kHz. It is demonstrated that the irradiation of weak laser can enhance the response of the transducer due to the nonlinear photothermal effect. The mechanical FM detection of modulated light is demonstrated using this bimetal transducer.
    Micro Electro Mechanical Systems, 2007. MEMS. IEEE 20th International Conference on; 01/2007
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    ABSTRACT: Micro-MRI is an imaging technique used to obtain information on cellular biochemistry by spatial mapping of 1H NMR relaxation times. The sensitivity and MRI resolution of solenoidal receive coils is superior to spiral coil geometries. We developed a new MEMS-based fabrication method promising to overcome many of the disadvantages of previously developed Micro-MRI systems.
    01/2007;
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    ABSTRACT: In this paper, a bimetallic thermal radiation microsensor with a dipole antenna for detecting electromagnetic waves ranging from infrared to terahertz region is designed, fabricated and evaluated. A cantilevered silicon-aluminum bimetal structure with an absorber at the end is employed as a thermal sensing element. On the basis of the resonant frequency change of the cantilever relying on photothermal conversion, the incident electromagnetic waves can be detected. The dipole antenna is integrated to enhance the electric field intensity at the sensing element and increase the sensitivity of the microsensor. This electric field enhancement effect is simulated by finite difference time domain simulation and it is found that the designed antenna can enhance the electric field several ten times. The frequency variation sensitivity to an incident light is found to be 11 Hz/muW Also, a thermal nose equivalent power of 2times10-10 W/radicHz is demonstrated.
    01/2007;
  • H G Xu, T Ono, M Esashi
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    ABSTRACT: We propose a hysteresis and drift compensation scheme using proportional-integral feedback control for a nanopositioning Pb(ZrTi)O3 (PZT) microstage. A multi-degree of freedom PZT microstage with integrated differential capacitive displacement sensors has been fabricated and tested, demonstrating the feasibility of compensating for hysteresis and creep. The feedback signal to the PZT actuators is fed from differential capacitive sensors of the displacement of the microstage. Experimental results show that the sensitivity of the displacement sensor is approximately 0.53 V µm−1. A maximum resolution of 16 nm is achieved when hysteresis is compensated for, and the minimum detectable variation of capacitance ΔC is 1.25 × 10−3 pF. The hysteresis of the system varies with the proportional gain Kp, integral time constant Ti and reference input frequency. By using feedback control with a proportional and integration (PI) controller, the hysteresis decreases from 30% in open-loop operation to approximately 1% in closed-loop operation at a gain of 20, when the frequency of the sine reference input is 1 Hz and Ti is 20 ms. Efficient compensation of hysteresis is validated by the closed-loop control, especially when the frequency of the reference input is low. Elimination of creep/drift is also verified by the closed-loop control.
    Journal of Micromechanics and Microengineering 11/2006; 16(12):2747. · 1.79 Impact Factor
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    K. Iwami, T. Ono, M. Esashi
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    ABSTRACT: Microelectromechanical systems (MEMS)-based near-field scanning optical microscopy (NSOM) probes with a bow-tie antenna structure consisting of two metal triangular electrodes separated by a narrow gap have been designed and fabricated. An electrostatic actuator is integrated on this bow-tie probe to decrease the gap width for enhancing the optical near-field intensity. A self-alignment process based on deep reactive ion etching and wet anisotropic etching is established to fabricate the symmetric bow-tie structure. The static and dynamic actuations of electrostatic actuators are examined. With the mechanical resonance of the antenna structure to lateral direction, NSOM imaging is performed in the visible range, and the subwavelength resolution beyond the diffraction limit of light is demonstrated
    Journal of Microelectromechanical Systems 11/2006; · 2.13 Impact Factor

Publication Stats

215 Citations
28.86 Total Impact Points

Institutions

  • 1997–2010
    • Tohoku University
      • Graduate School of Engineering
      Sendai-shi, Miyagi-ken, Japan
  • 2005
    • Vietnamese Academy of Science and Technology Institute of Information Technology
      Hà Nội, Ha Nội, Vietnam
  • 2004–2005
    • Pioneer Corporation
      Kawasaki Si, Kanagawa, Japan
    • Toho University
      Edo, Tōkyō, Japan
  • 2003
    • Beijing University of Aeronautics and Astronautics (Beihang University)
      • School of Mechanical Engineering and Automation
      Peping, Beijing, China