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Dive into the research topics where Yoshitsugu Tanaka is active.

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Featured researches published by Yoshitsugu Tanaka.


The Astrophysical Journal | 1987

Simultaneous Multifrequency Observations of the BL Lacertae Object Markarian 421

F. Makino; Yoshitsugu Tanaka; Masaharu Matsuoka; K. Koyama; H. Inoue; Kazumi Makishima; R. Hoshi; Satio Hayakawa; Y. Kondo

Simultaneous multifrequency observations of the BL Lac object Mrk 421 covering radio through X-ray wavelengths were performed on two occasions separated by 5 weeks in January and March 1984, and each observation was coordinated for about 1 week. Composite multifrequency spectra of the central nonthermal component were obtained at the two epochs after subtracting the optical and infrared light of the underlying galaxy. The spectra show the gradual steepening toward high frequency; the power law indices are about 0.1, about 0.6, and about 1.0 for radio, infrared-optical, and UV bands, respectively. The UV and optical-infrared fluxes decreased by about 20 percent in 5 weeks, while the radio flux remained stable. The X-ray flux decreased by a factor of about 2, and the change was more pronounced at hard X-rays, which suggest that X-ray emission possibly consists of two components. The degree of polarization at the optical band varied on the time scale of a few days, while the position angle remained unchanged. Physical parameters of Mrk 421 are discussed in terms of the synchrotron self-Compton model. 55 references.


Japanese Journal of Applied Physics | 2008

Nitrogen Profile Study for SiON Gate Dielectrics of Advanced Dynamic Random Access Memory

Shigemi Murakawa; Masashi Takeuchi; Minoru Honda; Shuichi Ishizuka; Toshio Nakanishi; Yoshihiro Hirota; Takuya Sugawara; Yoshitsugu Tanaka; Yasushi Akasaka; Akinobu Teramoto; Shigetoshi Sugawa; Tadahiro Ohmi

Nitrogen profile variations were systematically studied for the plasma nitridation process of the dynamic random access memory (DRAM) gate dielectrics, using angle-resolved X-ray photoelectron spectroscopy (AR-XPS), and their influences to the boron blocking and the device performances including negative bias temperature instability (NBTI) were investigated. Nitrogen atoms incorporated are localized in the surface vicinity within 1.5 nm of the thickness and at the peak positions around 0.5 nm. The high pressure and high temperature conditions of plasma nitridation are preferred for improving the NBTI and the tool productivity. Post nitridation anneal stabilizes the nitrogen atoms incorporated, and improves the immunity against the boron penetration into the gate dielectrics. Both of re-oxidation and the out-diffusion of nitrogen atoms take place simultaneously near the surface during the queue time after the plasma nitridation. Microwave plasma with the radial line slot antenna (RLSA) is a successful SiON gate insulator formation technology in the manufacturing of DRAM as well as logic devices.


The Japan Society of Applied Physics | 2007

Nitrogen Profile Study for SiON Gate Dielectrics of Advanced DRAM

Shigemi Murakawa; Masashi Takeuchi; Minoru Honda; Shu-ichi Ishizuka; Toshio Nakanishi; Yoshihiro Hirota; Takuya Sugawara; Yoshitsugu Tanaka; Yasushi Akasaka; Akinobu Teramoto; Shigetoshi Sugawa; Tadahiro Ohmi

Tokyo Electron Ltd., TBS Broadcast Center, 3-6 Akasaka 5-chome, Minato-ku, Tokyo 107-8481, Japan, Phone: +81-3-5561-7967 FAX: +81-3-5561-7396 E-mail: [email protected] Management of Science and Technology, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan Tokyo Electron AT Ltd., SPA Development and Engineering 1-8 Fuso-cho, Amagasaki, Hyogo 660-0891, Japan New Industry Creation Hatchery Center, Tohoku University, Sendai 980-8579, Japan


Archive | 2008

MANUFACTURING METHOD OF FIN-TYPE FIELD EFFECT TRANSISTOR

Hajime Nakabayashi; Takuya Sugawara; Takashi Kobayashi; Junichi Kitagawa; Yoshitsugu Tanaka


Archive | 2000

Vacuum processing apparatus for semiconductor process

Kenji Amano; Yoshitsugu Tanaka


The Astrophysical Journal | 1984

A very long X-ray burst with a precursor from XB 1715-321

Yoshio Tawara; Tsuneo Kii; Satio Hayakawa; Hideyo Kunieda; Kazuo Masai; Fumiaki Nagase; H. Inoue; K. Koyama; F. Makino; Kazumi Makishima; Masaharu Matsuoka; Toshiaki Murakami; M. Oda; Y. Ogawara; T. Ohashi; Noriaki Shibazaki; Yoshitsugu Tanaka; Sigenori Miyamoto; Hiroshi Tsunemi; K. Yamashita; Iwao Kondo


The Astrophysical Journal | 1981

Discovery of two new X-ray burst sources in the globular clusters Terzan 1 and Terzan 5

Kazumi Makishima; Takehisa Ohashi; Hiroo Inoue; K. Koyama; Masaharu Matsuoka; Toshiaki Murakami; M. Oda; Y. Ogawara; Noriaki Shibazaki; Yoshitsugu Tanaka; Iwao Kondo; Satio Hayakawa; Hideyo Kunieda; F. Makino; Kazuo Masai; Fumiaki Nagase; Yoshio Tawara; Sigenori Miyamoto; Hiroshi Tsunemi; K. da Yamashita


The Astrophysical Journal | 1984

Secular variation and short-term fluctuations of the pulse period of VELA X-1

Fumiaki Nagase; Satio Hayakawa; Hideyo Kunieda; Kazuo Masai; N. Sato; Yoshio Tawara; H. Inoue; K. Koyama; F. Makino; Kazumi Makishima; Masaharu Matsuoka; Toshiaki Murakami; M. Oda; Y. Ogawara; T. Ohashi; Noriaki Shibazaki; Yoshitsugu Tanaka; Sigenori Miyamoto; Hiroshi Tsunemi; K. Yamashita; Iwao Kondo


The Astrophysical Journal | 1998

ASCA Observation of the Distant Cluster of Galaxies Cl 0016+16 and Implication for H0

Akihiro Furuzawa; Yuzuru Tawara; Hideyo Kunieda; K. Yamashita; T. Sonobe; Yoshitsugu Tanaka; R. F. Mushotzky


Archive | 2007

Basal plate carrying table and basal plate processing device

Kenji Amano; Yoshitsugu Tanaka

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F. Makino

Japan Aerospace Exploration Agency

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K. Koyama

Columbia University Medical Center

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Fumiaki Nagase

Japan Aerospace Exploration Agency

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