Zobrazeno 1 - 10
of 15
pro vyhledávání: '"Keiichi Umeda"'
Autor:
Masato Uehara, Yuki Amano, Takaaki Mizuno, Yasuhiro Aida, Hiroshi Yamada, Keiichi Umeda, Morito Akiyama
Publikováno v:
physica status solidi (RRL) – Rapid Research Letters.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::8695c5d56c12d731007c3f8b0326bae0
https://doi.org/10.1002/pssr.202300087
https://doi.org/10.1002/pssr.202300087
Publikováno v:
2020 IEEE International Ultrasonics Symposium (IUS).
The use of finite element method (FEM) with a harmonic balance (HB) solver is investigated for analyzing and optimizing nonlinear MEMS resonators vibrating in kHz and MHz range. The FEM+HB combination allows the inclusion of both elastic and inertial
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::af3b20b05bbd5f827970dec1b9cfeb0d
https://doi.org/10.1109/ius46767.2020.9251743
https://doi.org/10.1109/ius46767.2020.9251743
Autor:
Tadayuki Okawa, Toshio Nishimura, Yuchi Goto, Keiichi Umeda, Allen Pangaro, Hitoshi Seki, Arata Suzuki, V. Kaajakari
Publikováno v:
2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum (EFTF/IFC).
A MEMS-based 32 kHz resonator is designed, simulated, and manufactured. The chip scale package (CSP) dimensions are 0.9 mm x 0.6 mm which is more than a 50% reduction in comparison to the smallest quartz crystal tuning fork resonator available today.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::0e7f8ba64eb2fe9bcd201855ecda2f89
https://doi.org/10.1109/fcs.2019.8856015
https://doi.org/10.1109/fcs.2019.8856015
Autor:
Keiichi Umeda, Takaaki Mizuno, M. Kobayashi, Atsushi Honda, Morito Akiyama, Toshimi Nagase, Y. Aida
Publikováno v:
2017 19th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS).
This paper reports on piezoelectric polarity inversion of AlN thin films by doping. The germanium doped aluminum nitride (GeAlN) thin films are grown by RF magnetron sputtering. Doping amount is varied from 0 to 23%. The maximum piezoelectric polarit
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::b2664549d500f598a5bef795a5acf47b
https://doi.org/10.1109/transducers.2017.7994440
https://doi.org/10.1109/transducers.2017.7994440
Publikováno v:
Applied Physics Letters. 114:012902
Wurtzite gallium nitride (GaN) has a polarity along the c-axis and piezoelectric properties the same as aluminum nitride. Since it has a high mechanical quality factor and high output sensitivity, it is expected to perform well in piezo micro-electro
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::883960dc71fee5fd6cb381971681ae76
https://doi.org/10.1063/1.5066613
https://doi.org/10.1063/1.5066613
Publikováno v:
Vacuum. 80:658-661
We improved both the thickness uniformity and crystallinity of Aluminum nitride (AlN) films deposited by off-axis sputtering. The results in thickness uniformity and X-ray rocking curve full-width at half-maximum (FWHM) of AlN (0 0 0 2) are achieved
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::3a35926fc84f074da2061f7e93ea6a3a
https://doi.org/10.1016/j.vacuum.2005.11.024
https://doi.org/10.1016/j.vacuum.2005.11.024
Publikováno v:
Scopus-Elsevier
The electrical dissipation in non-contact atomic force microscopy (NC-AFM) was investigated in connection with the displacement current flowing between a tip and a sample, both of which were in the bias circuit loop. Oligothiophene sub-monolayer film
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::9fc40dbf29675679bcefeb812f31019a
http://hdl.handle.net/2433/3581
http://hdl.handle.net/2433/3581
Autor:
Morito Akiyama, Masato Uehara, Yasuhiro Aida, Keiichi Umeda, Toshimi Nagase, Hokuto Shigemoto, Yuki Fujio
Publikováno v:
Applied Physics Letters. 111:112901
Aluminum nitride (AlN) is one of piezoelectric materials, which are eagerly anticipated for use in microelectromechanical systems (MEMS) applications such as communication resonators, sensors, and energy harvesters. AlN is particularly excellent in g
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::99da6954ea4b57a83600a2b1bfcfe69a
https://doi.org/10.1063/1.4990533
https://doi.org/10.1063/1.4990533
Autor:
Hirofumi Yamada, Shunji Watanabe, Kazumi Matsushige, Kei Kobayashi, Keiichi Umeda, Toru Fujii, Toshihisa Horiuchi, Shu Hotta
Publikováno v:
Applied Physics A. 72:S97-S100
We measured surface potential (SP) on a π-conju-gated thiophene oligomer monolayer film deposited on a metallic substrate by Kelvin probe force microscopy using a piezoelectric cantilever. Since the cantilever has a relatively large spring constant
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::6233e015cd24231f2ae9ec204af32d30
https://doi.org/10.1007/s003390100641
https://doi.org/10.1007/s003390100641
Publikováno v:
Vacuum. 83:672-674
We have evaluated the electrical performance of bulk acoustic wave (BAW) resonators in the range of resonance frequency from 5 to 20 GHz. The BAW resonators, consisting of a piezoelectric AlN film and top and bottom electrodes of Al/Ti films, were de
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::2403e50afd46fbf3c5d2d8b1f788f80e
https://doi.org/10.1016/j.vacuum.2008.04.044
https://doi.org/10.1016/j.vacuum.2008.04.044