Circuit-level requirements for MOSFET-replacement devices

Power consumption has grown to be the dominant challenge for continued CMOS scaling. This issue can be traced directly to the fact that the thermal voltage k <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</inf> T/q does not scale, limiting the extent to which the MOSFET threshold voltage (V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</inf> ) and hence the supply voltage (V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dd</inf> ) can be scaled. To circumvent this limit, alternative switching device designs [1,2] which can achieve ≪60 mV/dec sub-threshold swing (S) have been proposed and demonstrated. However, many of these fail to maintain improved I <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</inf> /I <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</inf> across a range of V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dd</inf> . In this paper, we apply circuit-level metrics to establish guidelines for assessing the promise of alternative switching devices for replacing the MOSFET.