A write cycle recording device includes a storage device and a controller. The storage device is corresponding to a memory block of a non-volatile memory. The storage device has a plurality of bits for recording a plurality of recorded writing loop counts corresponding to a plurality of writing operations of the memory block. The controller is configured to: perform a writing operation on the memory block; record a performed writing loop count of the writing operation; and, update a recorded writing loop count corresponding to the writing operation in the storage device according to the performed writing loop count.

Apparatuses and techniques are described for detecting latent defects in a memory device by considering both physical segment and logical segment fail bits in an erase operation. The erase operation involves performing a series of erase loops until the memory cells pass an erase-verify test. The passing of the erase-verify test is based on counting memory cells in different logical segments which fail the verify test and determining that the count is less than a logical segment threshold for each logical segment. Subsequently, the technique involves counting memory cells in each physical segment which fail the erase-verify test and determining whether the count is less than a physical segment threshold. If the count is equal to or greater than the physical segment threshold for one or more of the physical segments, the block of memory cells is marked as being bad.

A flash memory, a method of erasing the flash memory and an electronic system are disclosed. Each memory block in the flash memory is added with corresponding information bit(s) that store(s) information indicating whether erasure of the memory block has been completed before power-off. This allows easily finding out which memory block in the flash memory is undergoing an erase operation at the time of power-off. When the flash memory is powered on again, the information in the corresponding information bit(s) of the memory blocks may be read out and checked to determine whether there is any memory block of which the erasure had not been completed before the last power-off. If so, the memory blocks in the flash memory will be reprogrammed during the re-powering. This can avoid possible failure in reading data from some memory cells in the flash memory.

A system includes a memory device including a memory array including a plurality of wordline groups and control logic, operatively coupled with the memory array, to perform operation including causing a first erase verify to be performed sequentially with respect to each wordline group of the plurality of wordline groups, identifying a set of failing wordline groups determined to have failed the first erase verify, and causing a second erase verify to be performed sequentially with respect to each wordline group of the set of failing wordline groups.

Weak erase detection and mitigation techniques are provided that detect permanent failures in solid-state storage devices. One exemplary method comprises obtaining an erase fail bits metric for a solid-state storage device; and detecting a permanent failure in at least a portion of the solid-state storage device causing weak erase failure mode by comparing the erase fail bit metric to a predefined fail bits threshold. In at least one embodiment, the method also comprises mitigating for the permanent failure causing the weak erase failure mode for one or more cells of the solid-state storage device. The mitigating for the permanent failure comprises, for example, changing a status of the one or more cells to a defective state and/or a retired state. The detection of the permanent failure causing the weak erase failure mode comprises, for example, detecting the weak erase failure mode without an erase failure.

There is provided a method for operating a memory device for performing a program operation of programming data in selected memory cells among a plurality of memory cells. The method includes: applying a program voltage to the selected memory cells; verifying program states of memory cells programmed to any one program state among a plurality of program states distinguished based on a plurality of threshold voltages among the selected memory cells; and verifying an erase state of memory cells programmed to an erase state among the selected memory cells.

A multiphase programming scheme for programming a plurality of memory cells of a data storage system includes a first programming phase in which a first set of voltage distributions of the plurality of memory cells is programmed by applying a first plurality of program pulses to word lines of the plurality of memory cells, and a second programming phase in which a second set of voltage distributions is programmed by applying a second plurality of program pulses to the word lines of the plurality of memory cells. The second programming phase includes maintaining a margin of separation between two adjacent voltage distributions of the second set of voltage distributions after each of the second plurality of program pulses. This scheme achieves better margin using an aggressive quick pass approach, which helps with data recovery in case of power loss events.

A nonvolatile memory device includes a memory block with an unused line connected to dummy cells and used lines connected to normal cells, and a controller which applies an erase voltage to the memory block, applies an unused line erase voltage to the unused line, and applies a word line erase voltage to the used lines during an erase operation. The dummy cells are not programmed during a program operation while the normal cells are programmed, the unused line erase voltage transits from a first voltage to a floating voltage at a first time point, and the controller reads the dummy cells and controls at least one of the magnitude of the first voltage and the first time point based on the result of reading the dummy cells.

A non-volatile memory system performs an erase process followed by a program process to program blocks of memory cells. The erase process comprises erasing followed by erase verification. The system recovers data and records a strike for blocks that fail a read process. In response to a particular block having a strike, the system performs an odd/even compare process during the erase process for the particular blocks having the strike such that the odd/even compare process comprises determining whether a number of memory cells connected to even word lines that have a different erase verify result than memory cells connected to odd word lines is greater than a defect test threshold. The system retires blocks from further use for storing host data that fail the odd/even compare process even if the block passes erase verification.

Apparatuses and techniques are described for modifying program and erase parameters in a memory device in which memory cells can be operated in a single bit per cell (SLC) mode or a multiple bits per cell mode. In one approach, the stress on a set of memory cells in an SLC mode is reduced during programming and erasing when the number of program-erase cycles for the block in the SLC mode is below a threshold. For example, during programming, the program-verify voltage and program voltages can be reduced to provide a shallower than normal programming. During erasing, the erase-verify voltage can be increased while the erase voltages can be reduced to provide a shallower than normal erase. When the number of program-erase cycles for the block in the SLC mode is above the threshold, the program and erase parameters revert to a default levels.