Comprehensive modeling of NAND flash memory reliability: Endurance and data retention

Abstract

A reliability modeling solution including endurance and data retention is developed for NAND Floating Gate Flash memory. Endurance model with trap generation considers the tunneling oxide quality distribution with process effect. Electric field and tunneling current effect also have been included. The complicated trap effect on threshold voltage and Swing shift is well explained based on non-uniformly trapped charge distribution. Thermal emission with Poole-Frenkel model and tunneling from trap to substrate are included for data retention simulation. Dominant mechanisms under high and low temperature are discussed. Broaden phenomenon of threshold voltage distribution after high temperature data retention is modeled and demonstrated based on random trap variation in tunneling Oxide.