Subthreshold slope of accumulation-mode p-channel SOI MOSFETs

Abstract

There exists a well established model for the subthreshold slope of enhancement-mode MOSFETs. Indeed, the subthreshold slope is given by: S=kT/q ln10 (1+/spl alpha/) where /spl alpha/ is equal to the ratio C/sub bb//C/sub ox1/. In other words, /spl alpha/ is the ratio between the capacitance of the structure below the channel and that of the structure above it. C/sub bb/ is equal to C/sub depl/, C/sub si/ and (C/sub si/ in series with C/sub ox2/) in bulk, fully depleted (FD) SOI with back accumulation and fully depleted SOI devices, respectively. As the potential distribution in an accumulation-mode (AM) p-channel SOI MOSFET in the subthreshold regime is similar to that of an n-channel FD enhancement-mode (FDEM) device, the same analytical model can be used to determine S.<>