Nobumitsu Hirose

National Institute of Information and Communications Technology

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Toshiaki Matsui

National Institute of Information and Communications Technology

Akifumi Kasamatsu

National Institute of Information and Communications Technology

Yoshiyuki Suda

Tokyo University of Agriculture and Technology

Takahiro Tsukamoto

University of Electro-Communications

Takashi Mimura

Showa University

Shigeru Yoshimori

Kanagawa University

Matsuo Sekine

Tokyo Institute of Technology

Yoshinori Uzawa

National Astronomical Observatory of Japan

Norio Onojima

University of Yamanashi

Mitsuo Kawamura

NTN (Japan)

Cooperative Institutions

The University of Tokyo

Tokyo Institute of Technology

National Institute of Advanced Industrial Science and Technology

National Institute of Information and Communications Technology

Tohoku University

Osaka University

Kyoto University

Kyushu University

Nagoya University

Tokyo University of Agriculture and Technology

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Basic characteristics of the planar Josephson triode

IEICE Transactions on Fundamentals of Electronics Communications and Computer Sciences (1988)

Yuichi Harada Nobumitsu Hirose Shigeru Yoshimori Mitsuo Kawamura

Triode

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Citations (2)

Computational and Experimental Research on Buffet Phenomena of Transonic Airfoils

Springer eBooks (1989)

Nobumitsu Hirose Hiroyasu Miwa

Trailing edge

10.1007/978-3-642-83584-1_39

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Citations (12)

Properties of the Nb Thin-Film Nanobridges Prepared by Nanometer Fabrication Process

Japanese Journal of Applied Physics (1991)

Y. Harada Nobumitsu Hirose Yoshinori Uzawa Matsuo Sekine

We describe the properties of Nb thin-film nanobridges fabricated by means of our original nanometer-scale process. Our original nanofabrication techniques include the synthesis of a new electron beam (EB) resist and the use of CBrF 3 as an etchant for reactive ion etching (RIE). Fabricated nanobridges have high sensitivity of radiation and high reliability. It is observed that the properties of nanobridges can be changed by varying the bridge length and its thickness. We have also fabricated the series arrays and observed that they operate coherently.

Nanometre

10.1143/jjap.30.3933

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Citations (4)

A comparative study of effects of SiNx deposition method on AlGaN/GaN heterostructure field-effect transistors

Applied Physics Letters (2009)

Masataka Higashiwaki Zhe Chen Rongming Chu Yi Pei S. Keller

The effects of thin SiNx deposition on AlGaN/GaN heterostructure field-effect transistors were systematically studied by comparing their electrical and device characteristics. Two aspects of the thin SiNx film deposition were investigated: (i) the increase in two-dimensional electron gas (2DEG) density at the heterointerface and (ii) its capability as a gate insulating layer. Three different SiNx deposition methods were studied: catalytic chemical vapor deposition (Cat-CVD), metalorganic chemical vapor deposition (MOCVD), and plasma enhanced chemical vapor deposition (PECVD). A large increase in 2DEG density was obtained after SiNx deposition for all methods. The devices with MOCVD SiNx gate insulator showed a larger gate leakage current than those with the Cat-CVD and PECVD SiNx, implying that a thinning of the AlGaN surface barrier occurred due to Si diffusion into the AlGaN barrier during the high-temperature MOCVD process.

Deposition

10.1063/1.3079798

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Citations (44)

Enhancement in electrical properties of GaN heterostructure field‐effect transistor by Si atom deposition on AlGaN barrier surface

Physica status solidi. C, Conferences and critical reviews/Physica status solidi. C, Current topics in solid state physics (2009)

Norio Onojima Nobumitsu Hirose Takashi Mimura Toshiaki Matsui

Abstract This study demonstrates that deposition of Si atoms on AlGaN barrier surfaces in GaN heterostructure field‐effect transistors (HFETs) can modulate the electrical properties of the two‐dimensional electron gas (2DEG). The results of Hall measurements performed using the eddy current and four‐point van der Pauw methods showed that the sheet resistance of an AlGaN/GaN HFET sample without surface passivation increased from that of the unprocessed sample after post‐metallization annealing at 820 °C for ohmic contacts. In contrast, the sheet resistance of the Si‐deposited sample did not increase even after annealing. Furthermore, eddy current measurements for unprocessed wafers with and without Si deposition revealed that the sheet resistance can be reduced by depositing Si atoms, regardless of annealing. The effect of Si deposition on devices having a thin Al‐rich barrier layer was found to be significant. The deposition of Si atoms (2 nm) on the AlN barrier surface in an AlN/GaN HFET (AlN 2 nm) resulted in a remarkable decrease in the sheet resistance from 60356 to 388 Ω/sq. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Ohmic contact

Passivation

Barrier layer

10.1002/pssc.200880830

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Citations (2)

Static characteristic evaluation of low-temperature deposition process for SiGeHEMT by Sputter Epitaxy Method

The Japan Society of Applied Physics (2018)

Katsumi Okubo Y. Aoyagi Akira Motohashi Degura Kyouhei Nobumitsu Hirose

Deposition

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Millimeter wave devices: Research project on millimeter-wave semiconductor devices

Journal of the Communications Research Laboratory (2001)

Toshiaki Matsui K. Shinohara Masataka Higashiwaki Nobumitsu Hirose 松井敏明

Extremely high frequency

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S-N-S weaklink junctions fabricated by nanometer lithography

IEEE Transactions on Applied Superconductivity (1997)

Nobumitsu Hirose Hiroshi Ohta Toshiaki Matsui Makoto Fukuda

It is well known that the dimensions of the weak-link is the most important factor of its characteristics. However, the relationship between the dimensions and the characteristics of the weak-links are not clarified, because the geometrical dimensions are usually different from the effective dimensions, To clarify this relationship, we fabricated S-N-S (niobium as the superconductor and gold as the normal metal) weak-link junctions using electron beam lithography (EBL), reactive ion etching (RIE) and lift-off. The dimensions of the weak-links were controllable and the minimum width and length were 30 nm and 40 nm, respectively,.

Lift (data mining)

10.1109/77.621780

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Citations (6)

Implementation and results of a time accurate finite-volume Euler code in the NWT parallel computer

Elsevier eBooks (1996)

Luis P. Ruiz-Calavera Nobumitsu Hirose

Inviscid flow

Code (set theory)

Fortran

Feature (linguistics)

10.1016/b978-044482322-9/50077-3