ERASE AND PROGRAMMING TECHNIQUES TO REDUCE THE WIDENING OF STATE DISTRIBUTIONS IN NON-VOLATILE MEMORIES

摘要

Techniques are presented for use in memory devices to improve reliability and endurance by reducing the widening in state distributions, that occurs after multiple write/erase cycles. One set of techniques uses a pre-conditioning operation where a pulse series, which may include program and gentle erase, are applied to one or more wordlines while a voltage differential is applied in the wordline direction, bitline direction, or both. Another set of techniques uses a dual or multi-pulse program process, where an increased wordline-to-wordline differential used in the first pulse of a pair.