Simulation of Retention Characteristics in Double-Gate Structure Multi-Bit SONOS Flash Memory

Abstract

This paper presents a detailed study of the retention characteristics in scaled multi-bit SONOS flash memories. By calculating the oxide field and tunneling currents, we evaluate the charge trapping mechanism. We calculate transient retention dynamics with the ONO fields, trapped charge, and tunneling currents. All the parameters were obtained by physics-based equations and without any fitting parameters or optimization steps. The results can be used with nanoscale nonvolatile memory. This modeling accounts for the V_T shift as a function of trapped charge density, time, silicon fin thickness and type of trapped charge, and can be used for optimizing the ONO geometry and parameters for maximum performance.