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 memory system includes a semiconductor storage device including a memory cell array including a plurality of groups of memory cells, and a control circuit configured to perform, upon receipt of a write command, a write operation on one of the groups of memory cells, and a memory controller is configured to, when transmitting the write command to perform the write operation on the one of the groups of memory cells, determine a first write voltage value for the write operation based on a total number of write operations or erase operations that have been performed on the one of the groups of memory cells, and transmit the write command to the semiconductor storage device together with the determined first write voltage value.

According to one embodiment, a memory system includes a semiconductor memory device and a controller. The semiconductor memory device includes a first memory cell configured to store data. The controller is configured to output a first parameter and a first command. The first parameter relates to an erase voltage for a first erase operation with respect to the first memory cell. The first command instructs the first erase operation. The controller outputs the first command after outputting the first parameter to the semiconductor memory device.

A reducing peak current consumption in a memory device when performing a word line voltage refresh operation or a read operation. When a word line voltage refresh operation or read operation is performed for the first time after a memory device powers up, the operation is performed with a power-saving technique such as reducing a ramp up rate of a voltage pulse, ramping up the voltage pulse in multiple steps, initiating the ramp up for different groups of word lines in a block at different times, initiating the ramp up for different blocks of word lines at different times, and reducing the number of blocks which are refreshed concurrently. When an additional word line voltage refresh operation or read operation is subsequently performed, the power-saving technique can be omitted.

A method for detecting and isolating defective memory plane(s) of a non-volatile memory structure during a program verify operation, comprising: initiating, for each plane, a word line verify voltage level scan with a bit scan pass fail criterion and at a starting voltage located within an intended program threshold voltage distribution curve, incrementally decreasing the word line verify voltage by a predetermined offset until a specific condition of the scan is obtained, and storing the voltage at which the specific condition of the scan is obtained, wherein the stored voltage represents a voltage of an upper tail portion of an actual programmed threshold voltage distribution curve of the plane. The stored voltages of all of the memory planes of the structure are compared to determine which plane corresponds to the lowest stored voltage. A “fail” status is applied to the plane corresponding to the lowest stored voltage.

Various examples described herein are directed to systems and methods for generating data values using a NAND flash array. A memory controller may read a number of memory cells at the NAND flash array using an initial read level to generate a first raw string. The memory controller may determine that a difference between a number of bits from the first raw string having a value of logical zero and a number of bits from the first raw string having a value of logical one is greater than a threshold value and read the number of memory cells using a second read level to generate a second raw string. The memory controller may determine that a difference between a number of bits from the second raw string having a value of logical zero and a number of bits from the second raw string having a value of logical one is not greater than a threshold value and applying a cryptographic function using the second raw string to generate a first PUF value.

According to one embodiment, a memory system includes a nonvolatile memory and a memory controller configured to execute a patrol process, in response to a first command set from a host device. In the patrol process, the memory controller is configured to read first data from the nonvolatile memory, and not to output the first data to the host device.

Technology is provided for extending the useful life of a block of memory cells by changing an operating parameter in a physical region of the block that is more susceptible to wear than other regions. Changing the operating parameter in the physical region extends the life of that region, which extends the life of the block. The operating parameter may be, for example, a program voltage step size or a storage capacity of the memory cells. For example, using a smaller program voltage step size in a sub-block that is more susceptible to wear extends the life of that sub-block, which extends the life of the block. For example, programming memory cells to fewer bits per cell in the region of the block (e.g., sub-block, word line) that is more susceptible to wear extends the useful life of that region, which extends the life of the block.

Disclosed in some examples are improvements to data placement architectures in NAND that provide additional data protection through an improved NAND data placement schema that allows for recovery from certain failure scenarios.

The present disclosure stripes data diagonally across page lines and planes to enhance the data protection. Parity bits are stored in SLC blocks for extra protection until the block is finished writing and then the parity bits may be deleted.

A memory system includes a non-volatile memory chip that includes a memory cell array, and a memory controller. The memory controller is configured to perform a read operation on the non-volatile memory chip by instructing the non-volatile memory chip to perform a sensing operation to read data stored in the memory cell array, estimating a time when the read data becomes ready to be transferred from the non-volatile memory chip to the memory controller, and instructing the non-volatile memory chip, after the estimated time, to perform a transfer operation to transfer the read data to the memory controller.