Abstract: Techniques are presented to reduce the amount of read disturb on partially written blocks of NAND type non-volatile memory, both for when determining the last written word line in a block and also for data read. In both cases, non-selected word lines that are unwritten or, in the case of finding the last written word line, may be unwritten are biased with a lower read-pass voltage then is typically used. The result of such reads can also be applied to an algorithm for finding the last written word by skipping a varying number of word lines. Performance in a last written page determination can also be improved by use of shorter bit line settling times than for a standard read.

Abstract: In a three-dimensional nonvolatile memory, when a block erase failure occurs, zones within a block may be separately verified to see if some zones pass verification. Zones that pass may be designated as good zones and may subsequently be used to store user data while bad zones in the same block may be designated as bad and may not be used for subsequent storage of user data.

Abstract: Systems, apparatuses, and methods may be provided that adapt to trim set advancement. Trim set advancement may be a change in trim sets over time. A cell of a semiconductor memory may have a first charge level and be programmed with a first trim set. The cell may be reprogrammed by raising the first charge level to a second charge level that corresponds to the cell programmed with a second trim set.

Abstract: Systems and methods for metablock relinking may be provided. A first physical block of a first metablock may be determined to have a different health than a second physical block of a second metablock based on health indicators of the first and second physical blocks. Each of the health indicators may indicate an extent to which a respective one of the first and second physical blocks may be written to and/or erased before the respective one of the first and second physical blocks becomes defective. The first physical block of the first metablock may be replaced with the second physical block of the second metablock based on a determination that the health of the first physical block of the first metablock is different than the health of the second physical block of the second metablock.

Abstract: In a three-dimensional nonvolatile memory, when a block erase failure occurs, zones within a block may be separately verified to see if some zones pass verification. Zones that pass may be designated as good zones and may subsequently be used to store user data while bad zones in the same block may be designated as bad and may not be used for subsequent storage of user data.

Abstract: A 3D NAND stacked non-volatile memory device, comprising: a string comprising a plurality of non-volatile storage elements, the string comprises a channel and extends vertically through layers of the 3D stacked non-volatile memory device, and the plurality of storage elements are subdivided into different groups based on group assignments, each group of the different groups comprises multiple adjacent storage elements of the plurality of storage elements; and a control circuit in communication with the string, the control circuit, to perform a Pseudo Block Operation Mode.

Abstract: In a three dimensional NAND memory, increased threshold voltages in back gate transistors may cause program failures, particularly along word lines near back gates. When back gate transistor threshold voltages cannot be returned to a desired threshold voltage range then modified program conditions, including increased back gate voltage, may be used to allow programming.

Abstract: In a three-dimensional NAND memory in which a block contains multiple separately-selectable sets of strings connected to the same set of bit lines, sets of strings are zoned, and different operating parameters applied to different zones. Operating parameters for a zone are obtained from characterizing a reference set of strings in the zone.

Abstract: In a nonvolatile memory, hybrid blocks are initially written with only lower page data. The hybrid blocks later have middle and upper page data written. For high speed writes, data is written to a hybrid block and two or more Single Level Cell (SLC) blocks. The data from the SLC blocks are copied to the hybrid block at a later time in a folding operation.

Abstract: In a nonvolatile memory, hybrid blocks are initially written with only lower page data. The hybrid blocks later have middle and upper page data written. For high speed writes, data is written to a hybrid block and two or more Single Level Cell (SLC) blocks. The data from the SLC blocks are copied to the hybrid block at a later time in a folding operation.

Abstract: Layers in a multi-layer memory array are categorized according to likely error rates as predicted from their memory hole diameters. Data to be stored along a word line in a high risk layer is subject to a redundancy operation (e.g. XOR) with data to be stored along a word line in a low risk layer so that the risk of both being bad is low.

Abstract: A data storage device includes a memory and a controller. In a particular embodiment, a method is performed in the data storage device. The method is performed during a read threshold voltage update operation and includes determining a first read threshold voltage of a set of storage elements of a memory according to a first technique and determining a second read threshold voltage of the set of storage elements of the memory according to a second technique. The first read threshold voltage is different from the second read threshold voltage, and the first technique is different from the second technique.

Abstract: When a bad block is found in a nonvolatile memory array, the block is marked as a bad block so that it is not subsequently used. The block is also reconfigured as a bad block by increasing resistance of vertical NAND strings in the block by increasing threshold voltage of at least some transistors along vertical NAND strings, for example, select transistors or memory cell transistors.

Abstract: Layers in a multi-layer memory array are categorized according to likely error rates as predicted from their memory hole diameters. Data to be stored along a word line in a high risk layer is subject to a redundancy operation (e.g. XOR) with data to be stored along a word line in a low risk layer so that the risk of both being bad is low.

Abstract: When data from a portion of a three dimensional NAND memory array is determined to be uncorrectable by Error Correction Code (ECC), a determination is made as to whether data is uncorrectable by ECC throughout some unit that is larger than the portion. If modified read conditions provide ECC correctable data, the modified read conditions are recorded for subsequent reads of the larger unit.

Abstract: Portions of data stored in a three dimensional memory array are selected based on their locations for calculation of redundancy data. Locations are selected so that no two portions in a set of portions for a given calculation are likely to become uncorrectable at the same time. Selected portions may be separated by at least one word line and separated by at least one string in a block.

Abstract: In a charge trapping memory, data that would otherwise be likely to remain adjacent to unwritten word lines is written three times, along three immediately adjacent word lines. The middle copy is protected from charge migration on either side and is considered a safe copy for later reading. Dummy data may be programmed along a number of word lines to format a block for good data retention.

Abstract: Multiple bits of data are programmed together to each cell of a segment of a word line while other segments of the same word line are unprogrammed. Subsequently, additional segments are similarly programmed. Data is read from a partially programmed word line (with a mix of programmed and unprogrammed segments) using a single reading scheme.

Abstract: Multiple bits of data are programmed together to each cell of a segment of a word line while other segments of the same word line are unprogrammed. Subsequently, additional segments are similarly programmed. Data is read from a partially programmed word line (with a mix of programmed and unprogrammed segments) using a single reading scheme.

Abstract: In a three-dimensional NAND memory in which a block contains multiple separately-selectable sets of strings connected to the same set of bit lines, sets of strings are zoned, and different operating parameters applied to different zones. Operating parameters for a zone are obtained from characterizing a reference set of strings in the zone.