Sandisk Technologies Inc.

Western Digital Technologies, Inc.

Muhammad Masuduzzaman

Deepanshu Dutta

Xiang Yang

Huai-Yuan Tseng

Chin-Yi Chen

Dengtao Zhao

Ravi J Kumar

Tai-Yuan Tseng

Jiacen Guo

Jong Hak Yuh

Zhiping Zhang

Liang Li

Jiahui Yuan

Henry Chin

Mohan Dunga

Grishma Shah

Anubhav Khandelwal

Peng Zhang

Abhijith Prakash

Ke Zhang

Xue Bai Pitner

Kou Tei

Sujjatul Islam

Hiroyuki Mizukoshi

Piyush Dak

Erika Penzo

Xiaojia Jia

Xiaochang Miao

Minna Li

Gerrit Jan Hemink

Chao Qin

Linnan Chen

A memory apparatus and method of operation are provided. The apparatus includes memory cells connected to word lines and disposed in strings and configured to retain a threshold voltage corresponding to one of a plurality of data states. A control means is coupled to the word lines and the strings and is configured to successively apply one of a series of pulses of a program voltage to each selected one of the word lines to program the memory cells connected thereto during a program operation. The control means is also configured to utilize a time of a preliminary period of the program operation based on the one of the series of pulses of the program voltage being applied. The preliminary period of the program operation is before the series of pulses of the program voltage are applied to each selected one of the plurality of word lines.

Single-level cell pump skip program operation preliminary period timing optimization for non-volatile memory

A memory apparatus and method of operation are provided. The apparatus includes memory cells connected to word lines and disposed in memory holes coupled to bit lines. A control means successively applies each of a series of pulses of a program voltage to selected ones of the word lines while simultaneously applying one of a bit line program voltage and a bit line inhibit voltage to ones of the bit lines coupled to the memory holes containing groups of the memory cells connected to the selected ones of the plurality of word lines to program the groups of the memory cells with data. The control means maintains a voltage applied to ones of the plurality of bit lines as the bit line inhibit voltage in response to the ones of the plurality of bit lines remaining unselected when programming a next one of the groups of the memory cells.

Active current consumption save mode for non-volatile memory using fast programming

A storage device is provided that conditionally performs read refresh in blocks having higher P/E cycles or older programming times, while refraining from performing read refreshes in blocks having lower P/E cycles or recent programming times. The storage device includes a memory and a controller. The memory includes a block having cells. The controller performs a read refresh on the cells when a number of P/E cycles of the block exceeds an age threshold or after a threshold amount time has elapsed since data was programmed in the block. The controller may also refrain from performing read refreshes on the cells until the number of P/E cycles exceeds the age threshold or until a threshold amount of time has elapsed since the data is programmed. As a result, lower BER may occur due to wider Vt margins, while power and system overhead may be saved.

Data retention-specific refresh read

Technology is disclosed herein for smart verify in a memory system that has a four bit per cell program mode (or X4 mode) and also a three bit per cell program mode (or X3 mode). The X3 mode uses a three-bit gray code that is based on a four-bit gray code of the X4 mode. The memory system skips verify of states in the X3 mode, while using a considerable portion of the programming logic from the X4 mode. In one X3 mode the memory system skips B-state verify while the number of memory cells having a Vt above an A-state verify voltage is below a threshold. In one X3 mode the memory system determines whether to skip verify for a first set of data states based on a first test and determines whether to skip verify for a second set of data states based on a second test.

Hybrid smart verify for QLC/TLC die

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.

Low power multi-level cell (MLC) programming in non-volatile memory structures

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.

High speed multi-level cell (MLC) programming in non-volatile memory structures

Technology is disclosed herein for managing timing parameters when programming memory cells. Timing parameters used sub-clocks in an MLC program mode may also be used for those same sub-clocks in a first SLC program mode. However, in a second SLC program mode a different set of timing parameters may be used for that set of sub-clocks. Using the same set of timing parameters for the MLC program mode and the first SLC program mode saves storage space. However, the timing parameters for the MLC program mode may be slower than desired for SLC programming. A different set of timing parameters may be used for the second SLC program mode to provide for faster program operation. Moreover, the different set of timing parameters used for the faster SLC program mode do not require storage of a separate set of timing parameters.

Bundle multiple timing parameters for fast SLC programming

A memory apparatus and method of operation is provided. The apparatus includes memory cells connected to word lines. The memory cells are disposed in memory holes and grouped into a plurality of tiers. The memory cells are configured to retain a threshold voltage corresponding to one of a plurality of data states to store one bit as single-level cells and a plurality of bits as multi-level cells. The apparatus also includes a control means coupled to the word lines and the memory holes and configured to select a predetermined strobe quantity of the plurality of tiers of the memory cells separately for the memory cells operating as the single-level cells and the memory cells operating as the multi-level cells. The control means is also configured to trigger sensing of the predetermined strobe quantity of the plurality of tiers of the memory cells during a verify operation.

Memory apparatus and method of operation using state dependent strobe tier scan to reduce peak ICC

A storage device may be configured to determine data states for a first set of memory cells, of an array of memory cells, that are part of a logical N−1 neighboring word line that is adjacent to a selected word line. The storage device may be further configured to determine a program voltage configuration based on the data states. The storage device may be further configured to determine, using the program voltage configuration, a program operation on the selected word line to iteratively program respective memory cells, of a second set of memory cells that are part of the selected word line. Determining the data states, determining the program voltage configuration, and performing the program operation may be repeated until a program stop condition is satisfied.

Neighbor aware multi-bias programming in scaled BICS

The memory device includes a controller that is configured to program the memory cells of a selected word line in a plurality of program-verify iterations. During a verify portion at least one of the program-verify iterations, the controller determines a threshold voltage of at least one memory cell relative to a first verify low voltage VL1, a second verify low voltage VL2, and a verify high voltage VH associated with a data state being programmed. The controller also maintains a count of program-verify iterations since the at least one memory cell passed a verify high voltage of a previously programmed data state or discharges a sense node through a channel including the at least one memory cell and compares a discharge time to predetermined sense times associated with the first and second verify low voltages and with the verify high voltage.

Quick pass write programming techniques in a memory device

A storage device is provided that performs constant biasing in priority blocks, such as OTP memory blocks (fuse ROM) and flash memory blocks having a threshold number of P/E cycles. The storage device includes an OTP memory, a flash memory, and a controller. The OTP memory includes a block having a word line and a plurality of cells coupled to the word line. The flash memory includes another block having a word line and a plurality of cells coupled to this word line. The controller is configured to apply a constant bias to the word line of the OTP memory block and, in some cases to the word line of the flash memory block, between execution of host commands. As a result, lower bit error rates due to wider Vt margins may occur while system power may be saved through selective application of constant biasing.

Bias for data retention in fuse ROM and flash memory

A storage device is provided that applies pulsed biasing during power-up or read recovery. The storage device includes a memory and a controller. The memory includes a block having a word line and cells coupled to the word line. The controller applies a voltage pulse to the word line during power-up or in response to a read error. The voltage pulse may include an amplitude and a pulse width that are each a function of a number of P/E cycles of the block. The controller may also perform pulsed biasing during both power-up and read recovery by applying one or more first voltage pulses to the word line during power-up and one or more second voltage pulses to the word line in response to a read error. As a result, lower bit error rates due to wider Vt margins may occur and system power may be saved over constant biasing.

Pulsed bias for power-up or read recovery

A memory apparatus and method of operation are provided. The apparatus includes memory cells connected to one of a plurality of word lines and arranged in strings and configured to retain a threshold voltage corresponding to one of a plurality of memory states. A control circuit is coupled to the plurality of word lines and strings and is configured to erase the memory cells using a stripe erase operation in response to determining a cycle count is less than a predetermined cycle count maximum threshold. The control circuit is also configured to perform a dummy cycle operation in response to determining the cycle count is not less than the predetermined cycle count maximum threshold.

Memory apparatus and method of operation using periodic normal erase dummy cycle to improve stripe erase endurance and data retention

The non-volatile memory includes a control circuitry that is communicatively coupled to an array of memory cells that are arranged word lines. The control circuitry is configured to program the memory cells using a multi-pass programming operation which includes a first pass and a second pass. The first pass programs the memory cells to a first number of data states, and the second pass programs the memory cells to a greater second number of data states. For at least one word line, during the second pass, a voltage that is applied to at least one memory cell is reduced from a verify voltage by an offset which is determined as a function of a data state of an adjacent memory cell of an adjacent word line and wherein the first pass but not the second pass has been completed in the adjacent word line.

Modified verify in a memory device

A method reading memory using bi-directional sensing, including programming first memory cells coupled to a first word-line using a normal programming order; programming second memory cells coupled to a second word-line using a normal programming order; reading data from the first memory cells by applying a normal sensing operation to the first word-line; and reading data from the second memory cells by applying a reverse sensing operation to the second word-line. Methods also include receiving an error associated with reading data from the first memory cells; and then reading the data from the first memory cells by applying a reverse sensing operation to the first word-line. Method also include receiving an error associated with reading the data from the second memory cells; and then reading the data from the second memory cells by applying a normal sensing operation to the second word-line.

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Milpitas, CA, United States of America

Muhammad Masuduzzaman