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Makino, Takahiro; Deki, Manato; Iwamoto, Naoya; Onoda, Shinobu; Hoshino, Norihiro*; Tsuchida, Hidekazu*; Hirao, Toshio*; Oshima, Takeshi
IEEE Transactions on Nuclear Science, 60(4), p.2647 - 2650, 2013/08
Times Cited Count：19 Percentile：79.24(Engineering, Electrical & Electronic)Heavy ion induced anomalous charge collection was observed from 4H-SiC Schottky barrier diodes. It is suggested that the incident ion range with suspect to the thickness of the epi-layer of the SBD in key to understanding these observation and the understanding mechanism.
Oshima, Takeshi; Deki, Manato; Makino, Takahiro; Iwamoto, Naoya; Onoda, Shinobu; Hirao, Toshio*; Kojima, Kazutoshi*; Tomita, Takuro*; Matsuo, Shigeki*; Hashimoto, Shuichi*
AIP Conference Proceedings 1525, p.654 - 658, 2013/04
Times Cited Count：0 Percentile：0.00(Physics, Applied)Metal-Oxide-Semiconductor (MOS) capacitors were fabricated on n-type 4H-SiC epitaxial layers, and the leakage current through the gate oxide during heavy ion irradiation was investigated in order to evaluate dielectric breakdown induced by heavy ions (Single Event Gate Rupture: SEGR). The gate oxide at thickness ranges between 60 and 80 nm was formed using pyrogenic oxidation at 1100 
C for 60 min. Circular electrodes with 180 
diameter were formed using Al evaporation and a lift-off technique. The leakage current observed through the gate oxide was monitored during 18 MeV oxygen (O) or nickel (Ni) ions. As a result, although no significant difference in the value of the electric field at the dielectric breakdown (around 8.2 MV/cm) was observed between non-irradiated and 18 MeV-O irradiated samples, the value decreased to be 7.3 MV/cm in the case of 18 MeV-Ni ion incidence. The Linier Energy Transfer (LET) for 18 MeV-O is 7 MeV cm
/mg, and this value is smaller than that for 18 MeV-Ni (24 MeV cm/mg). Also, 18 MeV-Ni ions deposit energy in narrower regions than 18 MeV-O ions. Thus, it can be concluded that the high density of charge induced by 18 MeV-Ni ions triggers SEGR in SiC MOS capacitors.
Hazama, Masatoshi*; Abo, Satoshi*; Masuda, Naoyuki*; Wakaya, Fujio*; Onoda, Shinobu; Makino, Takahiro; Hirao, Toshio*; Oshima, Takeshi; Iwamatsu, Toshiaki*; Oda, Hidekazu*; et al.
Proceedings of 10th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-10) (Internet), p.115 - 118, 2012/12
Ogura, Shunta*; Komiyama, Takahiro*; Takahashi, Yoshihiro*; Makino, Takahiro; Onoda, Shinobu; Hirao, Toshio*; Oshima, Takeshi
Proceedings of 10th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-10) (Internet), p.127 - 129, 2012/12
We have investigated the transient current in a SOI p
n junction diode induced by single heavy-ions. The amount of radiation induced total collected charge exceeds the generated charge in active SOI layer because some of generated charge in handle substrate is collected through a BOX layer by displacement current. The displacement current is caused by the charges collected at surface of handle substrate due to an electric field in depletion layer. In this paper, we show that the amount of collected charge can be suppressed by reducing the width of depletion layer at the surface of handle substrate.
Duan, Z.*; Yang, Z.*; Hoshino, Daiki*; Hirao, Toshio; Taguchi, Mitsumasa; Ouchi, Hirokuni*; Yanagi, Yuichiro*; Nishioka, Yasushiro*
Molecular Crystals and Liquid Crystals, 567(1), p.28 - 33, 2012/09
Times Cited Count：3 Percentile：41.75(Chemistry, Multidisciplinary)
-Conjugated polymers and oligomers are of interest for applications to organic light emitting diodes, solar cells, and organic field effect transistors because of their unique photo-electronic properties. Thienyl-dibenzothiophene oligomers end-capped by hexylphenyl groups, 2,8-bis[5-(4-n-hexylphenyl)-2-thienyl]dibenzothiophene and 3,7-bis[5-(4-nhexylphenyl)-2-thienyl]dibenzothiophene, were synthesized by Stille cross-coupling reactions. The photo-physical and electrochemical properties of the synthesized oligomers were investigated by Ultraviolet-visible and photoluminescence spectroscopy, cyclic voltammogram, and thermal analyses, and showed appropriate energy band gaps and low HOMO energy levels. The synthesized oligomers are promising candidate materials for durable organic electronic devices.
-ray irradiated organic thin film transistors based on perfluoropentacene with polyimide gate insulatorTakayanagi, Yutaro*; Ouchi, Hirokuni*; Duan, Z.*; Okukawa, Takanori*; Yanagi, Yuichiro*; Yoshida, Akira*; Taguchi, Mitsumasa; Hirao, Toshio; Nishioka, Yasushiro*
Journal of Photopolymer Science and Technology, 25(4), p.493 - 496, 2012/08
Times Cited Count：0 Percentile：0.00(Polymer Science)Organic thin film fields effect transistors are expected to be used in spacecrafts/satellites because they can realize large-size, mechanical flexibility, light weight and low-cost devices. N-channel field effect transistors with a Si/polyimide(PI)/perfluoropentacene/Au structure were fabricated, and irradiated with -ray from Co source. The changes of the drain current vs. source/drain voltage characteristics were measured after every 200 Gy in silicon Gy(Si) irradiations up to the total dose of 1200 Gy(Si). The drain current gradually increased up to the total dose of 1200 Gy(Si). The threshold voltage decreased up to 400 Gy(Si), and gradually recovered above 600 Gy(Si). The mobility was almost unchanged up to 1200 Gy(Si). Those behaviors were explained by accumulation of positive trapped charge within the gate insulator PI near the interface. Evidence for the accumulation of interface traps was hardly observed.
Abo, Satoshi*; Masuda, Naoyuki*; Wakaya, Fujio*; Onoda, Shinobu; Makino, Takahiro; Hirao, Toshio; Oshima, Takeshi; Iwamatsu, Toshiaki*; Oda, Hidekazu*; Takai, Mikio*
Nuclear Instruments and Methods in Physics Research B, 269(20), p.2360 - 2363, 2011/10
Times Cited Count：2 Percentile：19.42(Instruments & Instrumentation)no abstracts in English
Co-ray irradiation effects on pentacene-based organic thin film transistorsCai, L.*; Hirao, Toshio; Yano, Hiroaki*; Duan, Z.*; Takayanagi, Yutaro*; Ueki, Hideharu*; Oshima, Takeshi; Nishioka, Yasushiro*
Materials Science Forum, 687, p.576 - 579, 2011/06
Times Cited Count：4 Percentile：80.32(Engineering, Electrical & Electronic)no abstracts in English
Kuboyama, Satoshi*; Maru, Akifumi*; Ikeda, Naomi*; Hirao, Toshio; Tamura, Takashi*
IEEE Transactions on Nuclear Science, 57(6), p.3257 - 3261, 2010/12
Times Cited Count：20 Percentile：77.45(Engineering, Electrical & Electronic)no abstracts in English
Maru, Akifumi*; Shindo, Hiroyuki*; Ebihara, Tsukasa*; Makihara, Akiko*; Hirao, Toshio; Kuboyama, Satoshi*
IEEE Transactions on Nuclear Science, 57(6), p.3602 - 3608, 2010/12
Times Cited Count：13 Percentile：63.67(Engineering, Electrical & Electronic)no abstracts in English
Abo, Satoshi*; Masuda, Naoyuki*; Wakaya, Fujio*; Onoda, Shinobu; Makino, Takahiro; Hirao, Toshio; Oshima, Takeshi; Iwamatsu, Toshiaki*; Oda, Hidekazu*; Takai, Mikio*
Proceedings of 9th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-9), p.72 - 75, 2010/10
no abstracts in English
Co -ray irradiated pentacene-based organic thin film field effect transistorsCai, L.*; Hirao, Toshio; Yano, Hiroaki*; Duan, Z.*; Takayanagi, Hideharu*; Ueki, Hideharu*; Oshima, Takeshi; Nishioka, Yasushiro*
Proceedings of 9th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-9), p.176 - 178, 2010/10
no abstracts in English
Maru, Akifumi*; Kuboyama, Satoshi*; Shindo, Hiroyuki*; Ebihara, Tsukasa*; Makihara, Akiko*; Hirao, Toshio; Tamura, Takashi*
Proceedings of 9th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-9), p.64 - 67, 2010/10
no abstracts in English
Takahashi, Yoshihiro*; Takeyasu, Hidenori*; Okazaki, Yuji*; Hirao, Toshio; Onoda, Shinobu; Oshima, Takeshi
Proceedings of 9th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-9), p.173 - 175, 2010/10
no abstracts in English
Ikeda, Naomi*; Kuboyama, Satoshi*; Maru, Akifumi*; Hirao, Toshio; Abe, Hiroshi; Tamura, Takashi*
Proceedings of 9th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-9), p.163 - 166, 2010/10
The trench structure showed an anomalously large degradation by heavy ion irradiation. For the trench structure, ions irradiated normal to the chip surface traverse the gate oxide along the entire length of the channel. Therefore, there is a possibility that the trapped holes resulting from the ion traverse introduce the anomalously large leakage current path. This phenomenon is apparently attributable to the microdose effect. In the previous report, the microdose effect was identified on both trench and planner type of power MOSFETs by real-time measurement of the threshold voltage shift during the heavy ion irradiation with very long range. In this study, detailed characterization of the microdose effects was carried out with several in species. As a result, several damage parameters introduced in the gate oxide by a single ion, such as physical damage size and trapped hole density in the damage region were estimated.
Makino, Takahiro; Onoda, Shinobu; Hirao, Toshio; Oshima, Takeshi; Kobayashi, Daisuke*; Ikeda, Hirokazu*; Hirose, Kazuyuki*
Proceedings of 9th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-9), p.169 - 172, 2010/10
Digital Single Event Transient (DSET) pulse-widths in an inverter cell fabricated with the 0.2 mm FD-SOI process were estimated from high-energy heavy-ion-induced transient current in a single n-type MOSFET fabricated with the 0.2 mm FD-SOI process. We verified that the estimation method is applicable to the DSET pulse-widths estimation in the case of high-energy heavy-ion irradiation.
Abo, Satoshi*; Masuda, Naoyuki*; Wakaya, Fujio*; Onoda, Shinobu; Hirao, Toshio; Oshima, Takeshi; Iwamatsu, Toshiaki*; Takai, Mikio*
Nuclear Instruments and Methods in Physics Research B, 268(11-12), p.2074 - 2077, 2010/06
Times Cited Count：3 Percentile：28.18(Instruments & Instrumentation)no abstracts in English
Lee, K. K.*; Laird, J. S.*; Oshima, Takeshi; Onoda, Shinobu; Hirao, Toshio; Ito, Hisayoshi
Materials Science Forum, 645-648, p.1013 - 1016, 2010/04
no abstracts in English
Makino, Takahiro; Kobayashi, Daisuke*; Hirose, Kazuyuki*; Takahashi, Daisuke*; Ishii, Shigeru*; Kusano, Masaki*; Onoda, Shinobu; Hirao, Toshio; Oshima, Takeshi
IEEE Transactions on Nuclear Science, 56(6), p.3180 - 3184, 2009/12
Times Cited Count：13 Percentile：63.49(Engineering, Electrical & Electronic)SET-induced soft-error rates (
s) of logic LSIs are estimated from SET pulse-widths measured in logic cells used in logic LSIs. The estimated rates are consistent with directly measured s for logic LSIs.
Makino, Takahiro; Onoda, Shinobu; Hirao, Toshio; Oshima, Takeshi; Kobayashi, Daisuke*; Hirose, Kazuyuki*
Proceedings of the 28th Symposium on Materials Science and Engineering, Research Center of Ion Beam Technology Hosei University, p.35 - 40, 2009/12
We want to reveal the relation between SET-induced soft-error rates (s) and SET pulse-width distribution to be able to reduce the with an SET filter like an RC filter or a temporal latch architecture. By considering the relation between 
and SET pulse-width, we can determine the minimum time constant for the SET filter to reduce the effectively. A theoretical estimation has been proposed to obtain in a logic LSI from SET pulse-widths measured in logic cells and the latch probability of SET pulses at flip-flops (FFs) used in logic LSIs. However, the estimation method has not been verified yet. In this paper, we verify the theoretical estimation method.
