Detecting programmed word lines based on NAND string current

A number (Nwl) of programmed word lines in a block of NAND strings is determined by measuring a reference combined current (Iref) in the block when all of the memory cells are in a conductive state. Subsequently, to determine if a word line is a programmed word line, an additional combined current (...

Full description

Saved in:
Bibliographic Details
Main Authors MUI MAN L, DONG YINGDA, AVILA CHIRS
Format Patent
LanguageEnglish
Published 17.02.2016
Subjects
INFORMATION STORAGE
PHYSICS
STATIC STORES
Online AccessGet full text

Cover

More Information
Summary:A number (Nwl) of programmed word lines in a block of NAND strings is determined by measuring a reference combined current (Iref) in the block when all of the memory cells are in a conductive state. Subsequently, to determine if a word line is a programmed word line, an additional combined current (Iadd) in the block is measured with a demarcation voltage applied to the selected word line. The selected word line is determined to be programmed word lines if Idd is less than Iref by at least a margin. Nwl can be used to adjust an erase-verify test of an erase operation by making the erase-verify test relatively hard to pass when the number is relatively small and relatively easy to pass when the number is relatively large. Or, Nwl can be used to identify a next word line to program in the block.
Bibliography:Application Number: CN201480031634