Impact of statistical variability and 3D electrostatics on post-cycling anomalous charge loss in nanoscale Flash memories

Abstract

This paper presents a detailed simulation investigation of the impact of statistical variability and 3D electrostatics on SILC distribution in nanoscale Flash memories. Considering a 1-TAT model we study the SILC statistics under stationary and dynamic retention conditions. Our results show that SILC is dispersed over the channel area due to non-uniform electrostatics in nanoscale devices. Further, the floating gate poly-silicon granularity plays a major role in determining the SILC distribution, depending on the gate polarity. Dynamic charge loss simulations highlight that the impact of 3D electrostatics is dominant over the cell-to-cell variability. Finally, we analyze the electron emission statistics on a single cell, showing that this gives rise to a lower SILC dispersion than an analytical Poisson charge loss statistics. Our results are fundamental to determine the degree of accuracy of 1D models for the post-cycling charge loss statistics simulation in nanoscale Flash memories. © 2013 IEEE.