Sandisk Technologies Inc.

Micron Technology Incorporated

Zhengyi Zhang

Yingda Dong

Ching-Huang Lu

Tomoko Ogura Iwasaki

Vinh Diep

Liang Pang

Lawrence Celso Miranda

Sheyang Ning

Johann Alsmeier

James K Kai

Henry Chin

Xuehong Yu

Vinh Q Diep

Dan Xu

Jian Feng Chen

Wei Zhao

Hong-Yan Chen

Caifu Zeng

Control logic in a memory device causes a programming pulse of a set of programming pulses associated with a programming algorithm to be applied to a selected wordline associated with a set of memory cells to be programmed to a target voltage level representing a programming level. Voltage levels of the selected wordline and one or more unselected wordlines of the memory array are discharged to approximately a ground voltage level and a bitline voltage level is applied to a bitline corresponding to the programming level. The selected wordline and a set of unselected wordlines are charged to approximately a pass voltage level followed by the discharge of the selected wordline to a reverse bias level to establish an erase voltage level on the set of memory cells. The control logic further performs a program verify operation corresponding to the programming level associated with the set of memory cells.

Charge loss acceleration during programming of memory cells in a memory sub-system

Control logic in a memory device causes a programming pulse of a set of programming pulses to be applied to a wordline associated with a memory cell of a memory device, where the memory cell is to be programmed to a target voltage level representing a first programming level. At a first time, first data is caused to be stored in a cache, the first data indicating that a threshold voltage of a memory cell exceeds the target voltage level. At a second time, the cache is caused to be refreshed to store second data indicating that the threshold voltage of the memory cell is less than the target voltage level. In view of the second data, a level shifting operation associated with the memory cell is caused to be executed.

In-line programming adjustment of a memory cell in a memory sub-system

Control logic in a memory device causes a first programming pulse of a set of programming pulses associated with a programming algorithm to be applied to a wordline associated with a memory cell to be programmed to a first target voltage level representing a first programming level. The control logic further performs a program verify operation corresponding to the first programming level to determine that a threshold voltage of the memory cell exceeds the first target voltage level. The control logic further causes first data to be stored in a cache, the first data indicating that the threshold voltage of the memory cell exceeds the first target voltage level. The cache is caused to be refreshed to store second data indicating that the threshold voltage of the memory cell is less than the first target voltage level. In view of the second data, a further programming pulse is caused to be applied to the wordline associated with the memory cell at a reduced programming stress level.

Processing logic in a memory device initiates a program operation on a memory array, the program operation comprising a program phase and a program verify phase. The processing logic further causes a negative voltage signal to be applied to a first selected word line of a block of the memory array during the program verify phase of the program operation, wherein the first selected word line is coupled to a corresponding first memory cell of a first plurality of memory cells in a string of memory cells in the block, wherein the first selected word line is associated with the program operation.

Detrapping electrons to prevent quick charge loss during program verify operations in a memory device

Apparatus having a string of series-connected memory cells, a plurality of access lines with each access line of the plurality of access lines connected to a control gate of a respective memory cell of the plurality of memory cells, and a controller for access of the string of series-connected memory cells and configured to cause the memory to increase a threshold voltage of a particular memory cell of the string of series-connect memory cells to a voltage level higher than a predetermined pass voltage to be received by a control gate of the particular memory cell during a read operation on the string of series-connected memory cells, and concurrently change a respective data state of each memory cell of a plurality of memory cells of the string of series-connected memory cells.

Apparatus for rapid data destruction

Apparatus having a string of series-connected memory cells comprising a plurality of principal memory cells and a plurality of dummy memory cells might have a controller configured to cause the apparatus to apply a first programming pulse to a particular dummy memory cell of the plurality of dummy memory cells sufficient to increase a threshold voltage of the particular dummy memory cell to a voltage level sufficient to cause the particular dummy memory cell to remain deactivated during a read operation on the string of series-connected memory cells, and to concurrently apply a second programming pulse to each principal memory cell of the plurality of principal memory cell sufficient to increase threshold voltages of at least a portion of the plurality of principal memory cells.

Apparatus and methods for rapid data destruction

Techniques are described for programming memory cells with reduced widening of the threshold voltage distributions. Bit line voltages are adjusted during verify tests for memory cells assigned to the upper data state in a pair of adjacent data states which are concurrently verified. An elevated bit line voltage is applied and then stepped up in successive program loops. A lower, fixed bit line voltage is used for verifying the lower data state in the pair of adjacent data states. In one option, the step size increases progressively over the program loops. In another option, the minimum level of the elevated bit line voltage is lower for higher data states. In another option, the minimum level of the elevated bit line voltage is set as a function of data states, program-erase cycles and/or temperature.

Multi-state programming in memory device with loop-dependent bit line voltage during verify

Program disturb is suppressed during a program recovery phase of a program operation in a memory device. The duration of the recovery phase can be increased when the risk of program disturb is greater due to factors such as temperature, the position of the selected word line, the number of program-erase cycles and the program pulse magnitude. In other approaches, the risk of program disturb is reduced by providing an early ramp down of the voltages of the drain-side word line relative to a ramp down of the voltages of the source-side word lines, providing an early ramp down of the bit line voltage of the inhibited NAND strings relative to the ramp down of the select gate voltage or setting a lower recovery voltage for the source-side word lines relative to the recovery voltage of the drain-side word lines.

Suppressing program disturb during program recovery in memory device

Techniques for reducing neighbor word line interference (NWI) of memory cells which are formed in a two-tier stack having a lower tier and an upper tier separated by an interface. In one approach, an upward word line programming order is used for a top portion of the top tier, and a downward word line programming order is used for a bottom portion of the top tier and for the bottom tier. Additionally, for memory cells which receive NWI from both adjacent word lines, options include programming fewer bits per cell, performing multi-pass programming and/or use lower verify voltages. Options also include increasing a control gate length of the memory cells and increasing a height of a dielectric region adjacent to the memory cells.

Reducing neighbor word line interference in a two-tier memory device by modifying word line programming order

Apparatuses and techniques are described for programming memory cells with a narrow threshold voltage (Vth) distribution in a memory device. In one approach, the final pass of a multi-pass program operation on a word line WLn includes applying a variable voltage to WLn+1 during verify tests on WLn. The variable voltage (Vread) can be an increasing function of the verify voltage on WLn, and thus a function of the data state for which the verify test is performed. In one approach, Vread on WLn+1 is stepped up with each increase in the verify voltage on WLn. The step size in Vread can be the same as, or different than, the step size in the verify voltage. Vread can be different for each different verify voltage, or multiple verify voltages can be grouped for use with a common Vread.

Adjusting voltage on adjacent word line during verify of memory cells on selected word line in multi-pass programming

A three-dimensional stacked memory device is configured to provide uniform programming speeds of different sets of memory strings formed in memory holes. In a process for removing sacrificial material from word line layers, a block oxide layer in the memory holes is etched away relatively more when the memory hole is relatively closer to an edge of the word line layers where an etchant is introduced. A thinner block oxide layer is associated with a faster programming speed. To compensate, memory strings at the edges of the word line layers are programmed together, separate from the programming of interior memory strings. A program operation can use a higher initial program voltage for programming the interior memory strings compared to the edge memory strings.

Grouping memory cells into sub-blocks for program speed uniformity

Apparatuses and techniques are described for programming a memory device with reduced temperature-based changes in the threshold voltage distribution (Vth). Different memory cells can have different values of a temperature coefficient, Tco, and high-Tco memory cells may tend to be at the lower tail of a Vth distribution. The memory cells are programmed using a first set of verify voltages which are temperature-independent. If the temperature at the time of the programming is less than a specified temperature, the high-Tco memory cells are identified and programmed further in a second pass using a second set of verify voltages which are temperature-dependent. Further, the second pass is configured to provide a narrower Vth distribution width than the first program pass. The second pass may use a smaller program pulse step size and/or an elevated bit line voltage.

Reducing widening of threshold voltage distributions in a memory device due to temperature change

Disturbs are reduced during programming and read operations for drain-side memory cells in a string by controlling dummy word line portions separately in selected and unselected sub-blocks. One or more of the dummy word line layers are separated so that they can be driven with different voltages. This allows the channel gradient to be optimized to reduce the likelihood of disturbs. In another aspect, a stack of alternating conductive and dielectric layers is formed in two parts, with lower pillars which comprise select gate transistors, source-side dummy memory cells and data memory cells, below upper pillars which comprise drain-side dummy memory cells and select gate transistors. The upper pillars are relatively narrow to provide a more compact structure. Moreover, the centerline of some upper pillars can be offset from the centerline of corresponding lower pillars to provide room for an isolation region.

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Mountain View, CA, United States of America

Zhengyi Zhang