SUBTHRESHOLD SLOPE OF LONG-CHANNEL, ACCUMULATION-MODE P-CHANNEL SOI MOSFETS

An analytical model for the subthreshold slope of the accumulation-mod e p-channeI SOI MOSFET is developed. The exact solution of the equatio ns reveals that the subthreshold swing is slightly larger (by a few pe rcent) than that of enhancement (inversion-mode) fully depleted SOI de vices. In most cases, however, the classical subthreshold slope expres sion developed for inversion-mode fully depleted SOI MOSFET can be use d as a good approximation for accumulation-mode devices, which means t hat the subthreshoId swing tends to the ideal value of S-0 = kT/q 1n(1 0) mV/dec if the buried oxide is sufficiently thick and if the interfa ce trap density is sufficiently low.