2022年第69回応用物理学会春季学術講演会

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13 半導体 » 13.5 デバイス/配線/集積化技術

[23p-E307-1~20] 13.5 デバイス/配線/集積化技術

2022年3月23日(水) 13:30 〜 19:00 E307 (E307)

遠藤 和彦(産総研)、堀 匡寛(静大)

17:45 〜 18:00

[23p-E307-16] Substrate Impurity Concentration Dependence of Sub-threshold Swing of Si n-channel MOSFETs at Cryogenic Temperature

〇(D)Minsoo Kang1、Hiroshi Oka2、Takahiro Mori2、Mitsuru Takenaka1、Kasidit Toprasertpong1、Shinichi Takagi1 (1.The Univ. of Tokyo、2.National Inst. of AIST)

キーワード:Cryogenic Temperature, Sub-threshold Swing, Substrate Impurity Concentration

The sub-threshold swing (SS) of Si nMOSFETs at cryogenic temperature has been reported to have the following characteristics: 1) saturation of SS with decreasing temperature, 2) increased inward bending (inflection) of SS as a function of the drain current (ID). To explain these two phenomena, Beckers et al.[1] have proposed models of band tail states and localized interface states near the band edge with a Gaussian distribution as Fig. 1. The Gaussian distribution has an amplitude N0 and a standard deviation W0/2, while the band tail has a characteristic tail of Wt. We have succeeded in representing experimental SS of Si nMOSFETs with a substrate impurity concentration of 2.0×1016 cm-3 in wide ranges of temperature and ID by assuming these band tail states and localized interface states [2]. However, the influence of the substrate impurity concentration (NA) on SS has not been studied so far. In this study, we have evaluated SS of nMOSFETs with different substrate impurity concentrations at 300 to 4 K and examined if the present model can quantitatively represent experimental SS.