Apparatuses and techniques are described for obtaining a threshold voltage distribution for a set of memory cells based on a user read mode. The user read mode can be based on various factors including a coding of a page and an increasing or decreasing order of the read voltages. The read process for the Vth distribution is made to mimic the read mode which is used when the memory device is in the hands of the end user. This results in a Vth distribution which reflects the user's experience to facilitate troubleshooting. In some cases, one or more dummy read operations are performed, where the read result is discarded, prior to a read operation which is used to build the Vth distribution.

According to one embodiment, a memory system includes a non-volatile memory and a controller. The memory includes a plurality of storage areas. Each of the storage areas includes a plurality of memory cells to which threshold voltages are set in accordance with data. The controller acquires a first threshold voltage distribution of memory cells in a first storage area of the storage areas. The controller acquires a second threshold voltage distribution of memory cells in a second storage area of the storage areas. The controller detects non-normalcy in the first storage area or the second storage area from a first divergence quantity between the first threshold voltage distribution and the second threshold voltage distribution.

Exemplary methods, apparatuses, and systems include receiving a plurality of read operations. The read operations are divided into a current set of a sequence of read operations and one or more other sets. The size of the current set is a first number of read operations. An aggressor read operation is selected from the current set. A first data integrity scan is performed on a victim of the aggressor and a first indicator of data integrity is determined based on the first data integrity scan. A scaling factor is determined using the indicator of data integrity and a number of program erase cycles for the portion of memory. The set size of read operations is adjusted to a second number of read operations using the scaling factor for a subsequent set.

Memory array structures providing for determination of resistive characteristics of access lines might include a first block of memory cells, a second block of memory cells, a first current path between a particular access line of the first block of memory cells and a particular access line of the second block of memory cells, and, optionally, a second current path between the particular access line of the second block of memory cells and a different access line of the first block of memory cells. Methods for determining resistive characteristics of access lines might include connecting the particular access line of the first block of memory cells to a driver, and determining the resistive characteristics in response to a current level through that access line and a voltage level of that access line.

Memory devices, systems including memory devices, and methods of operating memory devices are described, in which memory devices are configured to monitor word line characteristics. In one embodiment, the memory device includes a memory array including a word line (e.g., a local word line) and a word line driver coupled thereto. When the memory device activates the word line driver, the memory device may generate a diagnostic signal in response to the word line voltage reaching a threshold. Further, the memory device may generate a reference signal to compare the diagnostic signal with the reference signal. In some cases, the memory device may generate an alert signal based on comparing the diagnostic signal with the reference signal if the diagnostic signal indicates a symptom of degradation in the word line characteristics. The memory device may implement certain preventive and/or precautionary measures upon detecting the symptom.

Systems and methods of screening memory cells by modulating bitline and/or wordline voltage. In a read operation, the wordline may be overdriven or underdriven as compared to a nominal operating voltage on the wordline. In a write operation, the one or both of the bitline and wordline may be overdriven or underdriven as compared to a nominal operating voltage of each. A built-in self test (BIST) system for screening a memory array has bitline and wordline margin controls to modulate bitline and wordline voltage, respectively, in the memory array.

A semiconductor device includes a memory array arranged in a matrix, a plurality of word lines provided corresponding to memory cell rows, a word driver for driving one of the plurality of word lines, a plurality of row select lines connected to the word driver, and a row decoder for outputting a row select signal to the plurality of row select lines based on input row address information. According to the embodiment, the semiconductor device can detect a failure of the address decoder in a simple method.

A nonvolatile memory device includes a memory cell array, a voltage generator, a voltage path circuit and a wordline defect detection circuit. The memory cell array includes memory cells and wordlines connected to the memory cells. The voltage generator generates a wordline voltage applied to the wordlines. The voltage path circuit between the voltage generator and the memory cell array transfers the wordline voltage to the wordlines. The wordline defect detection circuit is connected to a measurement node between the voltage generator and the voltage path circuit. The wordline defect detection circuit measures a path leakage current of the voltage path circuit based on a measurement voltage of the measurement node to generate an offset value corresponding to the path leakage current in a compensation mode and determines defect of each wordline of the wordlines based on the offset value and the measurement voltage in a defect detection mode.

A system and method for read threshold calibration in a non-volatile memory are provided. Physical dies in the memory are divided into groups based on device-level parameters such as time and temperature parameters. An outlier die may be identified outside of the plurality of groups based on a comparison of a bit error rate (BER) indicator for each die to a threshold. For each group of dies, a read parameter is determined for at least one die, and applied to each of the plurality of dies of the group. The read parameter may be determined based on a threshold measurement of a representative one or more word lines.

A method for repairing a memory device with faulty memory cells. The method includes defining a RA environment comprising a location of each of the faulty memory cells and a plurality of SR and a plurality of SC. The method further includes repairing the faulty memory cells based on an RA training process using the defined RA environment and mapping of the location of each faulty memory cell with the plurality of SC or SR. The method further includes training, based on a determination that indicates the at least one faulty memory cell among the faulty memory cells is left unrepaired and the at least one SC or SR is remaining, a first NN to perform an action for repairing of the faulty memory cells such that a maximum number of faulty memory cells are reparable and a minimum number of SC and SR are utilized during the repairing.