Natural threshold voltage distribution compaction in non-volatile memory

摘要

In a non-volatile memory system, a programming operation applies programming pulses to a target word line, determines when a specified number of the non-volatile storage elements reach a defined verify level, and counts a specified number of the programming pulses after the specified number of the non-volatile storage elements reach the defined verify level. Upon completion of the counting, faster-programming storage elements are distinguished from slower-programming storage elements. Programming continues for of at least some of the faster-programming non-volatile storage elements, with an associated programming speed-based slow down measure imposed thereon, and for at least some of the slower-programming non-volatile storage elements without imposing a programming speed-based slow down measure.

主权项

1. A method for programming non-volatile storage elements of a target word line in a set of non-volatile storage elements, comprising:
applying programming pulses to the target word line; determining when a specified number of the non-volatile storage elements reach a defined verify level; counting a number of the programming pulses after the specified number of the non-volatile storage elements reach the defined verify level; in response to completion of the counting, distinguishing faster-programming non-volatile storage elements from slower-programming non-volatile storage elements, among the non-volatile storage elements of the target word line; and responsive to the distinguishing, continuing programming of at least some of the faster-programming non-volatile storage elements, with an associated programming speed-based slow down measure imposed thereon, and continuing programming of at least some of the slower-programming non-volatile storage elements without imposing a programming speed-based slow down measure.