Characterization and modeling of long term retention in SONOS non volatile memories

Abstract

An improved model to predict the charge retention dynamics of SONOS non volatile memory cells has been developed which accounts for the space and energy dependence of the trapped charge in the silicon nitride self consistently with the potential. From selected long term retention measurements (beyond 106 s) we were able to decouple the charge loss mechanisms and to derive an initial guess of the charge distribution profile. Without further adjustments of the parameters, the model reproduces a large set of long term retention measurements on devices featuring different gate stack, initial threshold voltage and operation temperature.