Modeling of Discrete Dopant Effects on Threshold Voltage Shift by Random Telegraph Signal

This paper discusses the discrete channel dopant effects on the threshold voltage shift by random telegraph signal (RTS) in MOSFETs. Appropriate grid spacing to incorporate discrete dopant effects in three dimensional device simulation is addressed to obtain consistent results with continuum limit. Considering discrete dopant effects, the threshold voltage shift of MOSFETs by RTS follows the log-normal distribution, while the threshold voltage itself follows the normal distribution. An analytical model for the distribution of the threshold voltage shift is also presented. The threshold voltage shift by RTS will become a serious concern in 50 nm flash memories and beyond