Reading method of 3D NAND flash memory

Abstract

The invention relates to a method for reading 3D NAND flash memory, the 3D NAND flash memory includes a plurality of memory cells arranged in an array within a three-dimensional space, forming a plurality of memory strings, the transistor at the top of each memory string is an upper select transistor, the upper selection tube is connected to a bit line, the transistor at the bottom of the string is a lower select transistor, a plurality of memory cells located within the same layer form a memory row, the gates of the memory cells located in the same memory row are all connected to the same word line, and the memory string in which the memory cells are to be read is taken as a selected string. The reading method is characterized in that the reading method comprises the steps of a preconduction stage and a reading stage, wherein a continuous precharge voltage is applied to the bit line in the preconduction stage; at the same time, the upper selection tube of the selected string and the upper selection tube of the unselected string are turned on, and the lower selection tube of the selected string and the lower selection tube of the unselected string are turned off.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for reading 3D NAND flash memory. Background technique [0002] In recent years, the development of flash memory (Flash Memory) is particularly rapid. The main feature of flash memory is that it can keep stored information for a long time without power on, and has the advantages of high integration, fast access speed, easy erasing and rewriting, etc. Has been widely used. In order to further increase the bit density (Bit Density) of the flash memory while reducing the bit cost (Bit Cost), three-dimensional flash memory (3D NAND) technology has been developed rapidly. [0003] In the 3D NAND flash memory structure, three-dimensional arrangements are made according to series and rows. In the prior art, when a certain storage unit is read, it often causes read interference to other storage units adjacent to the storage unit, resulting in data drift. [0004] How ...

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Problems solved by technology

[0003] In the 3D NAND flash memory structure, three-dimensional arrangements are made according to series and rows. In the prior art, when a certain storage unit is read, it often causes read interference to other storage units adjacent to the storage unit, resulting in data drift

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