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The subthreshold slope is a feature of a MOSFET's current–voltage characteristic. In the subthreshold region the drain current behaviour – though being controlled by the gate terminal – is similar to the exponentially increasing current of a forward biased diode. Therefore a plot of logarithmic drain current versus gate voltage with drain, source, and bulk voltages fixed will exhibit approximately log linear behaviour in this MOSFET operating regime. Its slope is the subthreshold slope. The subthreshold slope is also the reciprocal value of the subthreshold swing ''Ss-th'' which is usually given as:〔''Physics of Semiconductor Devices'', S. M. Sze. New York: Wiley, 3rd ed., with Kwok K. Ng, 2007, chapter 6.2.4, p. 315, ISBN 978-0-471-14323-9.〕 = gate-oxide capacitance = Thermal Voltage (thermal energy divided by the elementary charge) The minimum subthreshold swing of a conventional device can be found by letting which yields 60 mV/dec at room temperature (300 K). A typical experimental subthreshold swing for a scaled MOSFET at room temperature is ~70 mV/dec, slightly degraded due to short-channel MOSFET parasitics. A ''dec'' (decade) corresponds to a 10 times increase of the drain current ''ID''. A device characterized by steep subthreshold slope exhibits a faster transition between off (low current) and on (high current) states. ==References== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Subthreshold slope」の詳細全文を読む スポンサード リンク
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