A determination that a first programming operation has been performed on a particular memory cell can be made. A determination can be made, based on one or more threshold criteria, whether the particular memory cell has transitioned from a state associated with a decreased error rate to another state associated with an increased error rate. In response to determining that the particular memory cell has transitioned from the state associated with the decreased error rate to the another state associated with the increased error rate, an operation can be performed on the particular memory cell to transition the particular memory cell from the another state associated with the increased error rate to the state associated with the decreased error rate.

A 3D memory device may include a first set of memory layers, a second set of memory layers above the first set of memory layers, and a first dummy memory layer between the first and second memory layers. The 3D memory device may include a plurality of NAND memory strings each extending through the first and second set of memory layers and the first dummy memory layer. The 3D memory device may include a word line (WL) driving circuit that, when programming one of the first set of memory layers, may be configured to apply a second pre-charge voltage to the first dummy memory layer during the pre-charge period. The second pre-charge voltage may overlap with the first pre-charge voltage and ramp down prior to the first pre-charge voltage.

A method of programming a nonvolatile memory device includes performing a single-pulse program operation in a program loop, determining whether a condition is satisfied in the a program loop, and performing a multi-pulse program operation in a next program loop when the condition is satisfied. The single-pulse program operation includes applying a first program pulse and applying plural verification pulses, the multi-pulse program operation includes applying a second program pulse, applying a third program pulse, and applying plural verification pulses, and each of the second program pulse and the third program pulse has a level lower than a level of the first program pulse.

A memory device includes first and second memory strings, first and second word lines and a controller. The first memory string includes first and second memory cells, a first select transistor, a second select transistor, and a third select transistor between the first and second memory cells. The second memory string includes third and fourth memory cells, a fourth select transistor above the third memory cell, a fifth select transistor below the fourth memory cell, and a sixth select transistor between the third and fourth memory cells. The first word line is electrically connected to gates of the first and third memory cells. The second word line is electrically connected to gates of the second and fourth memory cells. The controller is configured to execute a read operation on one of the memory cells, the read operation including a first phase and a second phase after the first phase.

Apparatus might include an array of memory cells comprising a plurality of strings of series-connected memory cells and a controller for access of the array of memory cells, wherein the controller is configured to cause the apparatus to perform a sense operation on a selected memory cell of a string of series-connected memory cells, and to discharge access lines connected to the string of series-connected memory cells in a defined manner following the sense operation.

When programming an MLC memory device, the disturb characteristics of a program block having multiple memory cells are measured, and the threshold voltage variations of the multiple memory cells are then acquired based on the disturb characteristics of the program block. Next, multiple initial program voltage pulses are provided according to a predetermined signal level, and multiple compensated program voltage pulses are provided by adjusting the multiple initial program voltage pulses. Last, the multiple compensated program voltage pulses are outputted to the program block for programming the multiple memory cells to the predetermined signal level.

A memory device includes a memory cell array including memory blocks and a peripheral circuit coupled to the memory cell array. Each memory block includes memory strings each including dummy cells and select transistors, bit lines coupled to the memory strings, select lines including first select lines and second select lines, and one or more dummy word lines. Each select line coupled to the select transistors. The first select lines are closer to the bit lines than the second select lines. Each dummy word line is coupled to the respective dummy cells. The dummy word lines include a first dummy word line adjacent to either the first select lines or the second select lines. The peripheral circuit is configured to apply a turn-on voltage to all the first select lines, and apply a program voltage to the first dummy word line.

Methods and apparatus for NAND flash memory are disclosed. In an embodiment, a method is provided for programming a memory device having a plurality of memory chips that comprise multiple-level-cells. The method includes loading first data in a first chip, programming the first data into selected cells of the first chip using a single-level-cell (SLC) programming mode, and reprogramming the first data stored in the selected cells of the first chip to other cells of the first chip using a multiple-level-cell programming mode. The method also includes repeating the operations of loading, programming, and reprogramming for the remaining chips. The loading operations for the remaining chips begin at the completion of the loading operation for the first chip and occur in a non-overlapping sequential manner, and the loading operations for the remaining chips are performed in parallel with the programming and reprogramming operations of the first chip.

Apparatuses and techniques are described for detecting and isolating defective blocks of memory cells in a multi-plane operation such as program or erase. In one aspect, a program operation begins in a multi-plane mode, for one block in each plane. If fewer than all blocks complete programming by the time a trigger number of program loops have been performed, one or more unpassed blocks are programmed further, one at a time, in a single plane mode. If the one or more unpassed blocks do not complete programming when a maximum allowable number of program loops have been performed, they are marked as bad blocks and disabled from further operations. In another aspect, when a trigger number of program loops have been performed, one or more unpassed blocks are subject to a word line leakage detection operation.

A memory device includes unselected sub-block, which includes bit line; drain select (SGD) transistor coupled with bit line; a source voltage line; source select (SGS) transistor coupled with source voltage; and wordlines coupled with gates of string of cells, which have channel coupled between the SGS/SGD transistors. Control logic coupled with unselected sub-block is to: cause the SGD/SGS transistors to turn on while ramping the wordlines from a ground voltage to a pass voltage associated with unselected wordlines in preparation for read operation; cause, while ramping the wordlines, the channel to be pre-charged by ramping voltages on the bit line and the source voltage line to a target voltage that is greater than a source read voltage level; and in response to wordlines reaching the pass voltage, causing the SGD and SGS transistors to be turned off, to leave the channel pre-charged to the target voltage during the read operation.