A storage device is provided. The storage device includes a nonvolatile memory device including a first block and a second block, and a controller including processing circuitry configured to, predict a number of writes to be performed on the nonvolatile memory device using a machine learning model, determine a type of reclaim command based on the predicted number of writes, the reclaim command for reclaiming data of the first block to the second block, and issue the reclaim command.

Apparatuses and techniques are described for performing an operation which irreversibly prevents access to a set of memory cells. The operation provides a strong erase bias for select gate transistors of NAND strings. The erase bias induces a phenomenon in the select gate transistors which permanently increases their threshold voltages. This prevents access to the memory cells such as for program or read operations. The operation can involve one or more erase-verify iterations. In each erase-verify iteration, an erase bias is applied to the select gate transistors such as by charging up the channels of the NAND strings and holding a control gate voltage of the select gate transistors at a relatively low level, thereby causing a relatively high channel-to-control gate voltage.

An erasing method is used in a memory device. The memory device includes a string of memory cells and a controller, the string of memory cells including a plurality of special memory cells not for storing data and a plurality of main memory cells for storing data. The erasing method includes: the controller verifying if at least one special memory cell of the plurality of special memory cells has failed; the controller resetting the at least one special memory cell if the at least one special memory cell has failed; and the controller erasing the plurality of main memory cells.

A semiconductor memory device includes a plurality of conductive layers, a semiconductor layer opposed to the plurality of conductive layers, and an electric charge accumulation portion disposed between the semiconductor layer and the plurality of conductive layers. The electric charge accumulation portion includes a plurality of first electric charge accumulation portions opposed to the plurality of conductive layers, and a plurality of second electric charge accumulation portions disposed in positions different from the plurality of first electric charge accumulation portions. A distance between the first electric charge accumulation portion and the semiconductor layer is smaller than a distance between the second electric charge accumulation portion and the semiconductor layer. A distance between the second electric charge accumulation portion and the conductive layers is smaller than a distance between the first electric charge accumulation portion and the conductive layers.

A method of operating a storage device, including; performing, by a non-volatile memory, an erase operation on a block of memory in the non-volatile memory, where the non-volatile memory is coupled to a controller; receiving, by the non-volatile memory, a host-transaction within a first time period, where, the non-volatile memory is coupled to a host device; and suspending, by the non-volatile memory, an erase operation in response to receiving the host-transaction by: determining the erase operation has completed a charge phase; and suspending the erase operation during a pulse phase of the erase operation. The method additionally includes the non-volatile memory maintaining a loop counter and a pulse counter, where: the loop counter increments in response to completion of an erase loop, and the pulse counter increments in response to completion of an erase pulse, where the erase pulse is applied during a pulse phase of the erase operation.

An erasing method is used in a memory device. The memory device includes a string of memory cells and a controller, the string of memory cells including a plurality of special memory cells not for storing data and a plurality of main memory cells for storing data. The erasing method includes: the controller verifying if at least one special memory cell of the plurality of special memory cells has failed; the controller resetting the at least one special memory cell if the at least one special memory cell has failed; and the controller erasing the plurality of main memory cells.

An erasing method is used in a memory device. The memory device includes a string of memory cells and a controller, the string of memory cells including a plurality of special memory cells not for storing data and a plurality of main memory cells for storing data. The erasing method includes: the controller verifying if at least one special memory cell of the plurality of special memory cells has failed; the controller resetting the at least one special memory cell if the at least one special memory cell has failed; and the controller erasing the plurality of main memory cells.

An operating method of a non-volatile memory device including a plurality of memory cells respectively connected to a plurality of word lines is provided. The operating method includes applying an erase detect voltage to a selected word line of the plurality of word lines to perform an erase detect operation on memory cells connected to the selected word line in response to a program command, applying a program voltage to the selected word line after the erase detect operation, and counting a number of undererased cells of the memory cells on which the erase detect operation has been performed.

According to a certain embodiment, the semiconductor memory device includes a memory cell array, a control circuit, and a data register storing an erase verify fail flag. An erase target block is divided into word line groups. The control circuit includes: a counter configured to count the number of the erase verify fail flags to be output as a count value for each group; a plurality of counter registers configured to store the count value for each group; an arithmetic circuit configured to take a difference of the plurality of count values respectively stored in the plurality of counter registers and to output a result of the difference as a number of second fail flags; and a comparator configured to compare the number of criteria of the erase verify fail flag and the number of the second fail flags to be output as a memory state detected result.

A semiconductor memory device includes first and second bit lines, first and second memory transistors connected to the respective first and second bit lines, a source line connected to the first and second memory transistors, and a word line connected to gate electrodes of the first and second memory transistors. In an erase operation that erases data in the first and second memory transistors: a first erase voltage application operation is performed; an erase verify operation is performed on only one of the first and second memory transistors; and a second erase voltage application operation is performed without performing the erase verify operation on another of the first and second memory transistors.