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Hijikata, Yasuto*; Mitomo, Satoshi*; Matsuda, Takuma*; Murata, Koichi*; Yokoseki, Takashi*; Makino, Takahiro; Takeyama, Akinori; Onoda, Shinobu; Okubo, Shuichi*; Tanaka, Yuki*; et al.
Proceedings of 11th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-11) (Internet), p.130 - 133, 2015/11
Takeyama, Akinori; Matsuda, Takuma; Yokoseki, Takashi; Mitomo, Satoshi; Murata, Koichi; Makino, Takahiro; Onoda, Shinobu; Tanaka, Yuki*; Kandori, Mikio*; Yoshie, Toru*; et al.
Proceedings of 11th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-11) (Internet), p.134 - 137, 2015/11
Takeyama, Akinori; Matsuda, Takuma*; Yokoseki, Takashi*; Mitomo, Satoshi*; Murata, Koichi*; Makino, Takahiro; Onoda, Shinobu; Okubo, Shuichi*; Tanaka, Yuki*; Kandori, Mikio*; et al.
no journal, ,
Effect of -ray irradiation under high temperature and humidity circumstances on the electrical characteristics of Silicon Carbide (SiC) Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs) was investigated. In the case of irradiation under high humidity circumstance, trapped oxide and interface charges densities generated due to irradiation were smaller than those for irradiation in dry circumstance. It is concluded that humidity circumstance suppressed the degradation of the electrical properties due to irradiation including threshold voltage shift and leakage current.
Takeyama, Akinori; Mitomo, Satoshi*; Matsuda, Takuma*; Murata, Koichi*; Yokoseki, Takashi*; Makino, Takahiro; Onoda, Shinobu; Oshima, Takeshi; Okubo, Shuichi*; Tanaka, Yuki*; et al.
no journal, ,
Oxide thickness dependence of -ray irradiation response on Silicon Carbide (SiC) Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs) was investigated. As a result of irradiation, the threshold voltage V for both SiC MOSFETs with gate oxide of 30 nm or 60 nm thick shifted to negative voltage-side gently. However, the V for 60 nm thick more immediately decreased over 400 kGy. It is found that SiCMOSFETs with smaller thickness has a higher radiation tolerance.
Takeyama, Akinori; Murata, Koichi*; Mitomo, Satoshi*; Matsuda, Takuma*; Yokoseki, Takashi*; Makino, Takahiro; Onoda, Shinobu; Okubo, Shuichi*; Tanaka, Yuki*; Kandori, Mikio*; et al.
no journal, ,
Deterioration of electrical property of SiCMOSFETs due to irradiation was reduced compared with no biased ones, when the SiC MOSFETs with switching bias were irradiated. In order to clarify this mechanism, SiCMOSFETs were irradiated up to 50 kGy with switching bias applied to gate oxide from 4.5 to 0 V. As a result, the large negative shift of threshold voltage V due to irradiation with positive bias significantly recovered in the cases that the bias switched to zero. It shows electrical property of SiCMOSFETs were immediately relieved when applied bias was removed by switching.
Kobayashi, Takuma*; Nakanuma, Takato*; Suzuki, Asato*; Sometani, Mitsuru*; Okamoto, Mitsuo*; Yoshigoe, Akitaka; Hosoi, Takuji*; Shimura, Takayoshi*; Watanabe, Heiji*
no journal, ,
We investigated the reliability of nitrided SiC MOS devices in terms of oxide leakage and flatband voltage stability. Although nitrided MOS devices on non-basal planes are known to have superior on-state performances, we found that the nitridation not only leads to pronounced oxide leakage but also hampers the flatband voltage stability in response to electron and hole injection. In the presentation, we will show how the nitridation modifies the MOS interfaces based on the results of synchrotron radiation X-ray photoelectron spectroscopy and discuss the possible cause of reliability degradation.
Kobayashi, Takuma*; Nakanuma, Takato*; Suzuki, Asato*; Sometani, Mitsuru*; Okamoto, Mitsuo*; Yoshigoe, Akitaka; Shimura, Takayoshi*; Watanabe, Heiji*
no journal, ,
Together with a standard NO nitridation, a high channel mobility ( 100 cmVs) is obtained for SiC MOSFETs fabricated on non-basal planes, such as (1-100) m-face. Since these planes appear on the side wall of trench formed on (0001) Si-face, they can be directly applied to trench MOSFETs which have low on-resistance. Despite their advantages, the characteristics of MOS devices on non-basal planes, including the impact of nitridation, is not well investigated. In this work, we focused on SiC MOS devices on m-face and studied their physical and electrical characteristics in detail.
Onishi, Kentaro*; Kobayashi, Takuma*; Mizobata, Hidetoshi*; Nozaki, Mikito*; Yoshigoe, Akitaka; Shimura, Takayoshi*; Watanabe, Heiji*
no journal, ,
GaO interlayer at SiO/GaN interfaces is easily reduced during the annealing process, leading to threshold voltage instability of MOS devices. In this study, we formed SiO by sputter deposition to minimize the growth of unstable GaO interlayer. Furthermore, by performing oxygen and hydrogen annealing, a stable GaN MOS structure with good interface and insulating properties was realized.