Abstract: In order to inhibit memory cells from programming and mitigate program disturb, the memory pre-charges channels of NAND strings connected to a common set of control lines by applying positive voltages to the control lines and applying voltages to a source line and bit lines connected to the NAND strings. The control lines include word lines and select lines. The word lines include an edge word line. The memory ramps down the positive voltages applied to the control lines, including ramping down control lines on a first side of the edge word line, ramping down the edge word line, and performing a staggered ramp down of three or more control lines on a second side of the edge word line. After the pre-charging, unselected NAND strings have their channel boosted to prevent programming and selected NAND strings experience programming on selected memory cells.

Abstract: Read disturb audit techniques that include algorithmically applying audit verify voltages to erased wordlines in an open memory block are described. In an audit verify technique, a pass-through voltage ensured to be higher than any threshold voltage of any cell is applied to each wordline in an open memory block that includes one or more programmed memory cells, and an audit verify voltage lower than the pass-through voltage is applied to each erased wordline. A first bit count representing a number of non-conductive bitline(s) is determined and compared to a threshold value to determine whether to continue or discontinue block operation. In an audit verify and audit gap technique, the erased wordlines are divided into disjoint first and second groups, and an audit verify voltage and a non-verify voltage are alternatively applied to the groups in different audit verify stages.

Abstract: An apparatus is provided that includes a plurality of memory cells, logic circuits coupled to the memory cells and configured to store 4-bit data in each of the memory cells, and a control circuit coupled to the memory cells and the logic circuits. The control circuit configured to cause the logic circuits to store 3-bit data in each of the memory cells.

Abstract: A method of erasing memory cells in a memory device is provided. The method includes grouping a plurality of word lines into a first group, which does not include edge word lines, and a second group, which does include edge word lines. An erase operation is performed on the memory cells of the first and second groups until erase-verify of the memory cells of the first group passes. It is then determined if further erase of the memory cells of the second group is necessary. In response to it being determined that the additional erase operation is necessary, an additional erase operation is performed on at least some of the memory cells of the second group until erase-verify of the memory cells of the second group passes.

Abstract: The memory device includes a memory block with a plurality of memory cells, which are programmed to multiple bits per memory cell, arranged in a plurality of word lines. Control circuitry is provided and is configured to read the memory cells of a selected word line. The control circuitry separates the memory cells of the selected word line into a first group of memory cells, which are located on a side of the word line are near a voltage driver, and a second group of memory cells, which are located on an opposite side of the word line from the voltage driver. The control circuitry reads the memory cells of the first group using a first read mode and reads the memory cells of the second group using a second read mode that is different than the first read mode to reduce a fail bit count during read.

Abstract: A memory apparatus and method of operation are provided. The memory apparatus includes memory cells connected to word lines and disposed in memory holes. The memory cells are connected in series between a drain-side select gate transistor on a drain-side and connected to one of a plurality of bit lines and a source line on a source-side. A control means is configured to apply a first and a second select gate voltage to the drain-side select gate transistor while applying a predetermined source line voltage to the source line of selected ones of the memory holes in a predetermined grouping and a read level voltage to at least one of the word lines associated with the predetermined grouping. The control means counts the memory cells conducting during each of a first and a second read operation and adjusts the predetermined source line voltage accordingly.

Abstract: A method for programming a memory array of a non-volatile memory structure, the memory comprising a population of MLC NAND-type memory cells, wherein the method comprises applying: (1) an inhibit condition to one or more bit lines of the memory array, and (2) a zero voltage condition to one or more bit lines of the memory array such that less than half of the adjacent bit lines of the memory array experience a voltage swing between the inhibit condition and the zero voltage condition.

Abstract: To save power during a read process, NAND strings of each sub-block of a block have independently controlled source side select lines connected to source side select gates and drain side select lines connected to drain side select gates so that NAND strings of unselected sub-blocks can float and not draw current. To prevent read disturb in NAND strings of unselected sub-blocks, after all word lines are raised to a pass gate voltage, unselected word lines nearby the selected word line are lowered to respective intermediate voltages while lowering the voltage on the selected word line in order to achieve a channel potential gradient in the floated NAND strings of the unselected sub-blocks that does not result in read disturb. Subsequently, the selected word line is raised to the appropriate read compare voltage so the selected memory cells can be sensed.

Abstract: A method for programming a memory array of a non-volatile memory structure, wherein the memory array comprises a population of MLC NAND-type memory cells, and the method comprises: (1) in a first program pulse, programming selected memory cells according to a first programmable state and a second programmable state, and (2) in a second program pulse, programming the selected memory cells according to a third programmable state.

Abstract: Technology is disclosed herein for a memory system that compensates for different programming speeds in two sets of memory cells when reading those two sets of memory cells. The memory system programs a group of the memory cells to one or more data states. In one aspect, the memory cells are not verified during programming. The group has a first set of memory cells that program at a first speed and a second set of memory cells that program at a second speed. The memory system reads the first set of the memory cells with a first set of read parameters and reads the second set of the memory cells with a second set of read parameters. The first set of read parameters are different from the second set of read parameters to compensate for the different programming speeds.

Abstract: A method for performing an erase operation of a partially programmed memory block of a non-volatile memory structure. The method comprises: (1) applying an erase voltage bias level to a channel region of the memory block, (2) applying a word line voltage level to all programmed word line(s) of the memory block, (3) applying a “float” condition to all unprogrammed word line(s) of the memory block, and (4) applying an erase verify operation to all word line(s) of the memory block, wherein the “float” condition comprises omitting application of the word line voltage to the unprogrammed word line(s).

Abstract: A memory apparatus and method of operation are provided. The apparatus includes memory cells connected to word lines and disposed in strings. A control means is coupled to the word lines and the strings and is configured to ramp a voltage applied to a selected one of the word lines from a verify voltage to a reduced voltage during a program-verify portion of a program operation. The control means successively ramps voltages applied to each of a plurality of neighboring ones of the word lines from a read pass voltage to the reduced voltage beginning with ones of the plurality of neighboring ones of the word lines immediately adjacent the selected one of the word lines and progressing to ones of the plurality of neighboring others of the word lines disposed increasingly remotely from the selected one of the word lines during the program-verify portion of the program operation.

Abstract: A non-volatile memory system limits the amount of programming for a first type of group of non-volatile memory cells based on a first parameter such that a maximum number of programming pulses applied to the first type of group of non-volatile memory cells to program to the last data state after the first type of group of non-volatile memory cells completed programming to the other data states is X programming pulses. The non-volatile memory system limits the amount of programming for a second type of group of the non-volatile memory cells based on a second parameter such that a maximum number of programming pulses applied to the second type of group of non-volatile memory cells to program to the last data state after the second type of group of non-volatile memory cells completed programming to the other data states is Y programming pulses.

Abstract: An apparatus is provided that includes a word line coupled to a word line driver circuit, bit lines, a plurality of non-volatile memory cells each coupled to the word line and a corresponding one of the bit lines, and a control circuit coupled to the word line and the bit lines. The control circuit is configured to program the memory cells by causing the word line driver to apply a program pulse to the word line, and biasing each bit line to a corresponding bit line voltage that has a value that varies based on a distance between the word line driver and the corresponding bit line.

Abstract: The memory device includes a plurality of memory cells which are arranged in an array. The memory device further includes a plurality of bit lines that are coupled with the memory cells and a controller. The controller is configured to program the memory cells from an erased data state to three programmed data states in a programming operation that includes three programming pulses and zero verify operations using different patterns to dictate the application of inhibit voltages to the bit lines during each of the three programming pulses. The patterns include two pre-established patterns and additional patterns that are derived from the pre-established patterns using logic operations.

Abstract: The present disclosure provides for improving data retention reliability. During a programming operation associated with a memory cell, after the memory cell passes verification of a first verification voltage level, a second verification voltage level can be applied to the memory cell. Based on a comparison of the voltage in the memory cell with the second verification voltage level, a bit line voltage may be applied. Based on the applied bit line voltage, fast bits associated with the memory cell can be upshifted to an upper portion of a final voltage distribution associated with the programming operation. Upshifting the fast bits counteracts the downshifting effect in a final voltage distribution that may be caused by charge leakage or electron loss.

Abstract: Read disturb audit techniques that include algorithmically applying audit verify voltages to erased wordlines in an open memory block are described. In an audit verify technique, a pass-through voltage ensured to be higher than any threshold voltage of any cell is applied to each wordline in an open memory block that includes one or more programmed memory cells, and an audit verify voltage lower than the pass-through voltage is applied to each erased wordline. A first bit count representing a number of non-conductive bitline(s) is determined and compared to a threshold value to determine whether to continue or discontinue block operation. In an audit verify and audit gap technique, the erased wordlines are divided into disjoint first and second groups, and an audit verify voltage and a non-verify voltage are alternatively applied to the groups in different audit verify stages.

Abstract: A memory apparatus and method of operation are provided. The memory apparatus includes memory cells connected to word lines and disposed in memory holes. The memory cells are connected in series between a drain-side select gate transistor on a drain-side and connected to one of a plurality of bit lines and a source line on a source-side. A control means is configured to apply a first and a second select gate voltage to the drain-side select gate transistor while applying a predetermined source line voltage to the source line of selected ones of the memory holes in a predetermined grouping and a read level voltage to at least one of the word lines associated with the predetermined grouping. The control means counts the memory cells conducting during each of a first and a second read operation and adjusts the predetermined source line voltage accordingly.

Abstract: A memory device with adaptive sense time tables is disclosed. In order to maintain a desired (initial or preset) threshold voltage distribution, the sense time is adjusted as the program-erase cycle count increases. The program-erase cycle process tends to wear down memory cells, causing the QPW window to expand and the threshold voltage to widen. However, by adjusting (i.e., reducing) the sense time for increased program-erase cycles, the QPW window and the threshold voltage can be at least substantially maintained. Additionally, systems and methods for adjusting sense time based on die-to-die variations are also disclosed.

Abstract: In order to inhibit memory cells from programming and mitigate program disturb, the memory pre-charges channels of NAND strings connected to a common set of control lines by applying positive voltages to the control lines and applying voltages to a source line and bit lines connected to the NAND strings. The control lines include word lines and select lines. The word lines include an edge word line. The memory ramps down the positive voltages applied to the control lines, including ramping down control lines on a first side of the edge word line, ramping down the edge word line, and performing a staggered ramp down of three or more control lines on a second side of the edge word line. After the pre-charging, unselected NAND strings have their channel boosted to prevent programming and selected NAND strings experience programming on selected memory cells.