Abstract: Apparatuses, systems, methods, and computer program products are disclosed for read level determination. A block of non-volatile storage cells has a plurality of bit lines. A controller for a block is configured to perform a first read on a set of storage cells using a first read level for the bit lines. A controller is configured to determine a second read level for at least a portion of the bit lines based at least partially on a first read. A controller is configured to perform a second read on a set of storage cells using a second read level for at least a portion of bit lines.

Abstract: In solid-state memory, such as flash memory, a section of memory is typically erased prior to each time data is programmed therein. In contrast, systems and methods for programming a solid-state memory device with writes from different data sets without an intervening erase are disclosed. For example, the memory device may first erase a block and thereafter program the block with a first data set, with some cells in an erased state and other cells in a non-erased state. After programming the first data set into the block and without erasing the block, the memory device programs the block with a second data set that is at least partially different from the first data set. In this regard, some of the cells, which were in a non-erased state after programming with the first data set, are in an erased state after programming with the second data set.

Abstract: An erase operation includes one or more erase depth checks to detect the occurrence of shallow erased memory cells at the end of an erase process. Memory cells are subjected to erase and erase verification until erase verification success is achieved. At the end of successful erase verification, a subset of memory cells is read to detect an erase depth or level of the memory cells. If the erase depth check indicates that the subset memory cells are in a shallow erased condition, additional erasing and verification is performed.

Abstract: A split gate NAND flash memory structure is formed on a semiconductor substrate of a first conductivity type. The NAND structure comprises a first region of a second conductivity type in the substrate with a second region of the second conductivity type in the substrate, spaced apart from the first region. A continuous first channel region is defined between the first region and the second region. A plurality of floating gates are spaced apart from one another with each positioned over a separate portion of the channel region. A plurality of control gates are provided with each associated with and adjacent to a floating gate. Each control gate has two portions: a first portion over a portion of the channel region and a second portion over the associated floating gate and capacitively coupled thereto.

Abstract: Apparatuses, systems, methods, and computer program products are disclosed for erase depth control. One apparatus includes a block of non-volatile storage cells. A controller is configured to perform a first erase operation on a block of non-volatile storage cells. A controller for a block is configured to determine a first set of storage cells of the block having a faster erase speed than a second set of storage cells of the block based on a verify voltage threshold. A controller for a block is configured to perform a second erase operation on the block using different voltages for a first set of storage cells and a second set of storage cells of the block.

Abstract: Apparatuses, systems, methods, and computer program products are disclosed for read level determination. A block of non-volatile storage cells has a plurality of bit lines. A controller for a block is configured to perform a first read on a set of storage cells using a first read level for the bit lines. A controller is configured to determine a second read level for at least a portion of the bit lines based at least partially on a first read. A controller is configured to perform a second read on a set of storage cells using a second read level for at least a portion of bit lines.

Abstract: Techniques are provided for improving the accuracy of read operations of memory cells, where the threshold voltage of a memory cell can shift depending on when the read operation occurs. In one aspect, read voltages are set and optimized based on a time period since a last sensing operation. A timing device such as an n-bit digital counter may be provided for each block of memory cells to track the time. The counter is set to all 1's when the device is powered on. When a sensing operation occurs, the counter is periodically incremented based on a clock. When a next read operation occurs, the value of the counter is cross-referenced to an optimal set of read voltage shifts. Each block of cells may have its own counter, where the counters are incremented using a local or global clock.

Abstract: Reduced errors when sensing non-volatile memory are provided by applying a current spike or preconditioning current for a group of memory cells included a selected cell. During a sense operation, a preconditioning current can be passed through a group of non-volatile memory cells. The preconditioning current is provided prior to applying at least one reference voltage to a selected word line. The preconditioning current may simulate a cell current passing through the channel during a verification phase of programming. The preconditioning current can modify a channel resistance to approximate a state during verification to provide a more stable threshold voltage for the memory cells. Preconditioning currents may be applied selectively for select reference levels, select pages, and/or select operations. Selective application of preconditioning currents based on temperature is also provided.

Abstract: Techniques are provided for non-volatile storage self-detecting that a heating event has occurred to the non-volatile storage. One example of the heating event is an Infrared (IR) reflow process. In one aspect, a block of memory cells in a memory device are put through a number of program/erase cycles. A group of the memory cells in the cycled block are programmed to a reference threshold voltage distribution. Some time may pass after programming the cycled block. The memory device self-detects that there has been a heating event in response to a shift in the reference VT distribution being more than an allowed amount. The memory device may switch from a first programming mode to a second programming mode in response to detecting that the heating event has occurred.

Abstract: A method includes, responsive to a power-up event at a data storage device that includes a memory, reading a flag stored at the data storage device and determining that the flag has a first value indicating that a reflow operation has not previously been detected at the memory. The method also includes, in response to determining that the flag has the first value, performing reflow detection at the memory. The method further includes, in response to the reflow detection indicating that the reflow operation has occurred, setting the flag to a second value.

Abstract: A split gate NAND flash memory structure is formed on a semiconductor substrate of a first conductivity type. The NAND structure comprises a first region of a second conductivity type in the substrate with a second region of the second conductivity type in the substrate, spaced apart from the first region. A continuous first channel region is defined between the first region and the second region. A plurality of floating gates are spaced apart from one another with each positioned over a separate portion of the channel region. A plurality of control gates are provided with each associated with and adjacent to a floating gate. Each control gate has two portions: a first portion over a portion of the channel region and a second portion over the associated floating gate and capacitively coupled thereto.

Abstract: Methods for reducing cross-temperature dependent word line failures using a temperature dependent sensing scheme during a sensing operation are described. In some embodiments, during a read operation, the sensing conditions applied to memory cells within a memory array (e.g., the sensing time, source line voltage, or bit line voltage) may be set based on a temperature of the memory cells during sensing and a word line location of the memory cells to be sensed. In one example, the memory array may comprise a NAND memory array that includes a NAND string and the sensing time for sensing a memory cell of the NAND string and the source line voltage applied to a source line connected to a source end of the NAND string may be set based on the temperature of the memory cells during sensing and the word line location of the memory cells to be sensed.

Abstract: Methods for reducing cross-temperature threshold voltage distribution widening by applying a temperature dependent sensing scheme during read operations are described. In some embodiments, during a read operation, the sensing conditions applied to memory cells within a memory array (e.g., the sensing time and the read voltage applied to the memory cells during the sensing time) may be set and/or adjusted based on a temperature of the memory cells during the read operation, a previous temperature of the memory cells when the memory cells were programmed, and the programmed states of neighboring memory cells. In some cases, the sensing time for sensing a memory cell of a NAND string and the source voltage applied to a source line connected to the NAND string may be set based on the temperature of the memory cells during sensing and the previous temperature of the memory cells when the memory cells were programmed.

Abstract: A non-volatile storage system includes non-volatile storage elements and one or more managing circuits in communication with the non-volatile storage elements. The non-volatile storage elements are arranged in blocks including a first block reserved for system use and a second block. The first block stores a pre-determined data pattern that was written to the first block subsequent to system testing and prior to completion of manufacturing of the non-volatile storage system. Subsequent to completion of manufacturing of the non-volatile storage system, the one or more managing circuits sense information stored in the first block and determine an error metric for the sensed information with respect to the pre-determined data pattern. The one or more managing circuits determine that the system experienced an IR reflow process if the error metric was determined to satisfy the threshold.

Abstract: A split gate NAND flash memory structure is formed on a semiconductor substrate of a first conductivity type. The NAND structure comprises a first region of a second conductivity type in the substrate with a second region of the second conductivity type in the substrate, spaced apart from the first region. A continuous first channel region is defined between the first region and the second region. A plurality of floating gates are spaced apart from one another with each positioned over a separate portion of the channel region. A plurality of control gates are provided with each associated with and adjacent to a floating gate. Each control gate has two portions: a first portion over a portion of the channel region and a second portion over the associated floating gate and capacitively coupled thereto.

Abstract: A non-volatile storage system includes non-volatile storage elements and one or more managing circuits in communication with the non-volatile storage elements. The non-volatile storage elements are arranged in blocks including a first block reserved for system use and a second block. The first block stores a pre-determined data pattern that was written to the first block subsequent to system testing and prior to completion of manufacturing of the non-volatile storage system. Subsequent to completion of manufacturing of the non-volatile storage system, the one or more managing circuits sense information stored in the first block and determine an error metric for the sensed information with respect to the pre-determined data pattern. The one or more managing circuits determine that the system experienced an IR reflow process if the error metric was determined to satisfy the threshold.

Abstract: A method includes, responsive to a power-up event at a data storage device that includes a memory, reading a flag stored at the data storage device and determining that the flag has a first value indicating that a reflow operation has not previously been detected at the memory. The method also includes, in response to determining that the flag has the first value, performing reflow detection at the memory. The method further includes, in response to the reflow detection indicating that the reflow operation has occurred, setting the flag to a second value.

Abstract: Methods for reducing cross-temperature threshold voltage distribution widening by applying a temperature dependent sensing scheme during read operations are described. In some embodiments, during a read operation, the sensing conditions applied to memory cells within a memory array (e.g., the sensing time and the read voltage applied to the memory cells during the sensing time) may be set and/or adjusted based on a temperature of the memory cells during the read operation, a previous temperature of the memory cells when the memory cells were programmed, and the programmed states of neighboring memory cells. In some cases, the sensing time for sensing a memory cell of a NAND string and the source voltage applied to a source line connected to the NAND string may be set based on the temperature of the memory cells during sensing and the previous temperature of the memory cells when the memory cells were programmed.

Abstract: Methods for reducing cross-temperature dependent word line failures using a temperature dependent sensing scheme during a sensing operation are described. In some embodiments, during a read operation, the sensing conditions applied to memory cells within a memory array (e.g., the sensing time, source line voltage, or bit line voltage) may be set based on a temperature of the memory cells during sensing and a word line location of the memory cells to be sensed. In one example, the memory array may comprise a NAND memory array that includes a NAND string and the sensing time for sensing a memory cell of the NAND string and the source line voltage applied to a source line connected to a source end of the NAND string may be set based on the temperature of the memory cells during sensing and the word line location of the memory cells to be sensed.

Abstract: A set of non-volatile storage elements are subjected to a programming process in order to store data. During the programming process, one or more verification operations are performed to determine whether the non-volatile storage elements have reached their target. Non-volatile storage elements being programmed to a first set of one or more targets are verified to determine whether they have reached their target and are locked out of further programming if it is determined that they have reached their target. Non-volatile storage elements being programmed to the second set of one or more targets are tested to determine the number of fast programming bits. When the number of fast bits for a particular target is greater than a threshold, then programming stops for the non-volatile storage elements being programmed to the particular target.