A non-volatile memory device, described herein, comprises: a plurality of memory strings and at least one control circuit in communication with the non-volatile memory cell array. The at least one control circuit is configured to perform, for the plurality of memory strings, one erase-verify iteration in an erase operation including determining whether at least one memory string of the plurality of memory strings passes an erase-verify test. The at least one control circuit is configured to, if the at least one memory string passes the erase-verify test, inhibit the at least one memory string for erase including ramping up, to an erase voltage, of a voltage applied to a gate of a SGD transistor of the at least one memory string and to perform a next erase-verify iteration in the erase operation for remaining memory strings of the plurality of memory strings other than the at least one memory string.

A variety of applications can include memory systems that have one or more memory devices capable of performing memory operations on multiple blocks of memory in response to a command from a host. For example, improvement in erase performance can be attained by erasing multiple blocks of memory by one of a number of approaches. Such approaches can include parallel erasure followed by serial verification in response to a single command. Other approaches can include sequential erase and verify operations of the multiple blocks in response to a single command. Additional apparatus, systems, and methods are disclosed.

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.

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.

According to one embodiment, a semiconductor memory device includes: a first memory cell; a second memory cell; a first word line; a second word line; and a first bit line. The device is configured to execute a first operation, a second operation, and a third operation to write data into the first memory cell. In the first operation, a first voltage is applied to the second word line. In the second operation, after the first operation, a second voltage higher than the first voltage is applied to the second word line. In the third operation, after the second operation, a third voltage higher than the second voltage is applied to the first word line, and a fourth voltage lower than both the second voltage and the third voltage is applied to the second word line.

An electronic device, and an over-erase detection and elimination method for memory cells are provided; the method includes: performing an erase operation on a specified area; selecting all the memory cells in the selected area one by one; measuring a threshold voltage of a selected memory cell for over-erase detection to see if it is less than a normal erase threshold voltage; if not, selecting the next memory cell for over-erase detection, and if yes, then performing a soft-write operation on the selected memory cell; after the soft-write operation, performing over-erase detection again to see whether the threshold voltage of the selected memory cell is within a normal threshold range; and if not, performing a soft-write operation again, and if yes, the next memory cell is selected for over-erase detection, until the threshold voltages of all the memory cells selected for erasure are within the normal threshold range.

A memory system according to an embodiment includes a first bit line, a source line, a first word line, a second word line, a first memory pillar and a control circuit. The control circuit performs a first verify operation to first and second memory cells, a second verify operation to the first memory cell, a third verify operation to the second memory cell and a write operation or a read operation with a lower voltage in accordance with a request from an external device.

According to one embodiment, a semiconductor memory device includes: a first memory cell; a second memory cell; a first word line; a second word line; and a first bit line. The device is configured to execute a first operation, a second operation, and a third operation to write data into the first memory cell. In the first operation, a first voltage is applied to the second word line. In the second operation, after the first operation, a second voltage higher than the first voltage is applied to the second word line. In the third operation, after the second operation, a third voltage higher than the second voltage is applied to the first word line, and a fourth voltage lower than both the second voltage and the third voltage is applied to the second word line.

The invention provides a storage structure and an erase method thereof, which can perform an erase operation on memory blocks B.sub.1 . . . B.sub.n, where n is an integer greater than or equal to 2. The storage structure includes a first memory bank, a second memory bank and a controller, wherein the memory blocks are sequentially alternately arranged in the first memory bank and the second memory bank. The controller is used to control the memory blocks to sequentially undergo an erase operation. The erase operation includes sequentially performing a first process and a second process. When memory block B.sub.i undergoes the second process, the memory block B.sub.i+1 undergoes the first process, where i ∈ [1, n−1].