Unexpected equivalent-oxide-thickness dependence of the subthreshold swing in tunnel field-effect transistors

Tunnel field-effect transistors (TFETs) exhibiting a minimum subthreshold swing (SS) of 27 mV/decade were successfully fabricated using conventional planar HfO2/Si-gate-stack structures. However, an unexpected SS degradation with increasing equivalent oxide thickness (EOT) was observed compared with...

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Bibliographic Details
Published in:Applied physics express 2014-02, Vol.7 (2), p.24201
Main Authors: Mori, Takahiro, Yasuda, Tetsuji, Fukuda, Koichi, Morita, Yukinori, Migita, Shinji, Tanabe, Akihito, Maeda, Tatsuro, Mizubayashi, Wataru, O'uchi, Shin-ichi, Liu, Yongxun, Masahara, Meishoku, Miyata, Noriyuki, Ota, Hiroyuki
Format: Article
Language:English
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Summary:Tunnel field-effect transistors (TFETs) exhibiting a minimum subthreshold swing (SS) of 27 mV/decade were successfully fabricated using conventional planar HfO2/Si-gate-stack structures. However, an unexpected SS degradation with increasing equivalent oxide thickness (EOT) was observed compared with the simulated results obtained under the assumption of ideal band-to-band tunneling. We found that the poor subthreshold operation was governed by a thermally activated process, suggesting trap-assisted tunneling that occurs with traps near the metallurgical pn junction. Furthermore, we discuss the effect of the observed EOT-sensitive SS degradation on device production.
ISSN:1882-0778
1882-0786
DOI:10.7567/APEX.7.024201