Non-volatile storage with shared bit lines and flat memory cells

摘要

A non-volatile storage system is disclosed that includes pairs (or another number) of NAND strings (or other groupings of memory cells) in the same block being connected to and sharing a common bit line. By sharing bit lines, less bit lines are needed in the storage system. Using less bit lines reduces the space needed to implement the storage system. Each NAND string will have two drain side select gates. The non-volatile storage system will have two drain side selection lines each connected to one of the two drain side select gates so that the NAND strings sharing a bit line can be individually selected. To allow proper selection of a NAND string using the select gates, the select gates will be subjected to non-volatile programming in order to set the threshold voltage of the select gates to an appropriate level.

主权项

1. A method of operating a non-volatile storage, comprising:
with respect to multiple groups of non-volatile storage elements that each comprise multiple connected data non-volatile storage elements and multiple select gates on a common side of the data non-volatile storage elements, performing non-volatile programming of at least one of the select gates for each group to allow independent selection of the groups from another group connected to a common bit line, wherein each of the groups further includes at least one dummy select gate and at least one connected dummy select line, the performing non-volatile programming comprises programming dummy select gates using the connected dummy select line to allow a connected bit line to be cut off, and programming at least one subset of the select gates for each group is performed while the bit line is cut off.