US Patent 11935593 Dummy cell resistance tuning in NAND strings

An apparatus includes a control circuit configured to connect to memory cells connected in series in NAND strings. Each NAND string includes a plurality of data memory cells coupled to a plurality of data word lines in series with a plurality of dummy memory cells connected to a plurality of dummy word lines. The control circuit configured to apply a first dummy word line voltage to one or more dummy word lines of the plurality of dummy word lines in a verify step of a program operation to program data memory cells. The control circuit is configured to apply a second dummy word line voltage to the one or more dummy word lines in a read operation to read the data memory cells.