Patents by Inventor Xiang Yang

Xiang Yang has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20240386930
    Abstract: A memory device is provided and includes a memory block that has a plurality of memory cells that are arranged in a plurality of word lines. The memory device also includes a plurality of word line switch transistors that are electrically coupled with the plurality of word lines. Some of the word line switch transistors have a first width and some of the word line switch transistors have a second width that is different than the first width. By providing the word line switch transistors with different widths, the size of a word line switch area in the memory device can be optimized.
    Type: Application
    Filed: August 1, 2023
    Publication date: November 21, 2024
    Applicant: Western Digital Technologies, Inc.
    Inventors: Mohan Vamsi Dunga, Xiang Yang, Keyur Payak
  • Patent number: 12148478
    Abstract: A non-volatile memory system comprises a plurality of non-volatile memory cells divided into three or more tiers. The memory cells can be programmed, erased and read. In order to achieve uniform erase speed for the three or more tiers, the erase process comprises applying a larger voltage bias to control gates of non-volatile memory cells in the outer tiers than the voltage bias applied to control gates of non-volatile memory cells in one or more inner tiers.
    Type: Grant
    Filed: September 26, 2022
    Date of Patent: November 19, 2024
    Assignee: SanDisk Technologies LLC
    Inventors: Xiang Yang, Masaaki Higashitani, Abhijith Prakash, Dengtao Zhao
  • Publication number: 20240379170
    Abstract: Technology is disclosed herein for a storage system and method for multi-stage discharge of a read pass voltage. In an aspect, the voltage on unselected word lines is reduced from the read pass voltage to an intermediate voltage during a first stage near the end of a read operation. A read reference voltage on the selected word line may be changed (e.g., increased) to the intermediate voltage during the first stage. During a second stage the voltage on the unselected word lines may be reduced from the intermediate voltage to a final voltage. The voltage on the selected word line may also be decreased during the second stage from the intermediate voltage to the final voltage. The multi-stage discharge of the read pass voltage may reduce peak current consumption (e.g., peak Icc) in a final portion of the read operation.
    Type: Application
    Filed: July 27, 2023
    Publication date: November 14, 2024
    Applicant: Western Digital Technologies, Inc.
    Inventors: Albert Bor Kai Chen, Xiang Yang, Jiahui Yuan
  • Publication number: 20240379175
    Abstract: Technology is disclosed herein for a storage system that mitigates erase saturation when erasing memory cells. If erase does not pass after a number of erase loops, the storage system applies a program pulse to memory cells on faster to erase NAND strings. However, memory cells on slower to erase NAND strings are inhibited from programming. The program pulse increases the Vt of memory cells on the faster to erase NAND strings. Then, another erase loop is performed. The process may continue with additional loops, with each loop programming the memory cells on the faster to erase NAND strings followed by an erase pulse to all NAND strings and erase verify. Over-erase of the memory cells on the faster to erase NAND strings is therefore prevented. Moreover, slower to erase NAND strings that may otherwise be a bottleneck do not prevent successful completion of the erase.
    Type: Application
    Filed: July 27, 2023
    Publication date: November 14, 2024
    Applicant: Western Digital Technologies, Inc.
    Inventors: Yi Song, Jiahui Yuan, Jiacen Guo, Xiang Yang
  • Patent number: 12142315
    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.
    Type: Grant
    Filed: May 26, 2022
    Date of Patent: November 12, 2024
    Inventors: Xiang Yang, Muhammad Masuduzzaman, Jiacen Guo
  • Publication number: 20240371444
    Abstract: The memory device includes a memory block with a plurality of memory cells that are arranged in a plurality of word lines. The plurality of word lines include a selected word line, a pair of neighboring word lines that are immediately adjacent the selected word line, and a plurality of non-neighboring word lines that are not immediately adjacent the selected word line. Circuitry can perform a sensing operation on at least one memory cell in the selected word line. During the sensing operation, the circuitry is configured to apply a reference voltage to the selected word line, apply different first and second pass voltages to the neighboring word lines, and apply a third pass voltage that is different than the first and second pass voltages to the plurality of non-neighboring word lines. The circuitry is further configured to sense a threshold voltage of the at least one memory cell.
    Type: Application
    Filed: August 1, 2023
    Publication date: November 7, 2024
    Applicant: Western Digital Technologies, Inc.
    Inventors: Dengtao Zhao, Xiang Yang, Peng Zhang
  • Publication number: 20240363168
    Abstract: The memory device includes a chip with at least one voltage pump and a plurality of planes. The planes have arrays of memory cells that can be programmed and erased. At least some of the planes are at different distances from the at least one voltage pump. The memory device further includes control circuitry that is configured to program and erase the memory cells. The control circuitry is further configured to supply at least one voltage to a selected plane of the plurality of planes during a programming operation or an erase pulse and adjust the at least one voltage that is supplied to the selected plane by a parameter that is determined based on a distance between the selected plane and the at least one voltage pump.
    Type: Application
    Filed: August 4, 2023
    Publication date: October 31, 2024
    Applicant: Western Digital Technologies, Inc.
    Inventors: Abhijith Prakash, Xiang Yang
  • Publication number: 20240363178
    Abstract: The memory device includes a memory block with a plurality of memory cells that are arranged in a plurality of word lines and in a plurality of channels. The memory device also includes circuitry that is configured to conduct a hole pre-charge operation to inject holes into the plurality of channels. The hole pre-charge operation includes applying a first voltage to the plurality of word lines to make the plurality of memory cells conductive to holes and applying a voltage to the channels from one side of the memory block to inject holes into the channels.
    Type: Application
    Filed: August 8, 2023
    Publication date: October 31, 2024
    Applicant: Western Digital Technologies, Inc.
    Inventors: Jiacen Guo, Xiang Yang
  • Publication number: 20240363177
    Abstract: A memory apparatus and method of operation are provided. The apparatus includes drain-side select gate transistors for coupling to a drain-side of memory holes of and configured to retain a transistor threshold voltage. The memory holes are arranged in rows comprising strings. The rows include semi-circle rows comprising the memory holes being partially cut by a slit half etch and full circle rows comprising the memory holes not cut. A control means is coupled to the drain-side select gate transistors of the memory holes and is configured to determine whether a downshift recovery trigger event has occurred in a plurality of memory operations. In response to determining the downshift recovery trigger event has occurred, the control means programs the transistor threshold voltage of the drain-side select gate transistors of the memory holes in at least one of the semi-circle rows to a target transistor threshold voltage.
    Type: Application
    Filed: July 26, 2023
    Publication date: October 31, 2024
    Applicant: Western Digital Technologies, Inc.
    Inventors: Abhijith Prakash, Xiang Yang
  • Publication number: 20240355401
    Abstract: To improve programming performance in NAND memory, while maintaining programming accuracy and reducing program disturb, the channel pre-charge phase before a programming pulse can be eliminated. Instead, a read recovery phase after the program verify directly discharges a selected word line from the verify voltage to a negative word line voltage, with non-selected word lines being directly discharged from the read bypass voltage to the negative word line voltage. From the negative word line voltage, the word lines are then ramped up to ground and then on the bias levels of the following programming pulse. These conditions can drive electrons from the charge storage region of the selected memory cell, resulting in a high degree of channel boosting and much less program disturb. Variations of the technique can be applied to NAND memory operable in a sub-block mode where it can be difficult to use the typical channel pre-charge.
    Type: Application
    Filed: July 3, 2023
    Publication date: October 24, 2024
    Applicant: SanDisk Technologies LLC
    Inventors: Wei Cao, Xiang Yang, Peng Zhang
  • Publication number: 20240347122
    Abstract: A memory package includes a plurality of memory dies, each of which has a plurality of memory blocks with arrays of memory cells. The memory dies include user data dies that contain user data and an XOR die that contains XOR data. The memory package also includes circuitry for reading the user data and the XOR data. The circuitry is configured to detect a read error during a read operation in a failed die of the plurality of user data dies and read some of the user data of the user data dies besides the failed die and reading some of the XOR data of the XOR die. The circuitry is also configured to perform a read recovery operation that includes an XOR operation using, as inputs, the user data of the user data dies besides the failed die and the XOR data of the XOR die.
    Type: Application
    Filed: June 26, 2024
    Publication date: October 17, 2024
    Inventors: Xiang Yang, Deepanshu Dutta, Luca Fasoli
  • Patent number: 12112812
    Abstract: Non-volatile memory cells are programmed by pre-charging channels of unselected non-volatile memory cells connected to a selected data word line, boosting the channels of unselected non-volatile memory cells connected to the selected data word line after the pre-charging and applying a program voltage pulse to selected non-volatile memory cells connected to the selected data word line while boosting. The pre-charging includes applying pre-charge voltages to one set of data word lines and dummy word line(s) as well as applying overdrive voltages to another set of data word lines connected to already programmed memory cells. At the end of the pre-charging, the dummy word lines are ramped down to a resting voltage prior to lowering the data word lines to one or more resting voltages.
    Type: Grant
    Filed: August 10, 2022
    Date of Patent: October 8, 2024
    Assignee: SanDisk Technologies LLC
    Inventors: Jiacen Guo, Dengtao Zhao, Xiang Yang
  • Patent number: 12112800
    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.
    Type: Grant
    Filed: May 26, 2022
    Date of Patent: October 8, 2024
    Assignee: SanDisk Technologies LLC
    Inventors: Xiang Yang, Deepanshu Dutta, Muhammad Masuduzzaman, Jiacen Guo
  • Publication number: 20240319888
    Abstract: In NAND memory, data sanitization allows a relatively small unit of data (e.g., less than a block) to be effectively destroyed by increasing threshold voltages of memory cells from their programmed threshold voltage to the highest threshold state. To reduce the amount of disturb on memory cells not selected for data sanitization, prior to applying a program voltage to a target word line, a hole based pre-charge operation is performed. More specifically, for NAND strings having a memory cell selected for data sanitation, prior to applying a programming pulse to the corresponding word line, a soft erase operation is performed. After biasing the memory cells and select gates of the NAND strings to a low voltage, a soft erase voltage pulse is applied to the source lines and bit line to pre-charge the NAND string channels with holes.
    Type: Application
    Filed: July 3, 2023
    Publication date: September 26, 2024
    Applicant: SanDisk Technologies LLC
    Inventors: Wei Cao, Jiacen Guo, Xiang Yang
  • Publication number: 20240304262
    Abstract: The memory device an array of memory cells arranged in a word lines and a one common source line (CELSRC) driver. Control circuitry is configured to program the memory cells of a selected word line in a plurality of program loops. During the program loops, the control circuitry sets a voltage of the CELSRC driver to approximately zero Volts, applies a verify voltage to the selected word line, applies a pass voltage to unselected word lines, and applies a bit line voltage to a bit line that is coupled to a memory cell to be sensed. During at least one early program loop for a given data state, the control circuitry increases the bit line voltage or increases the pass voltage. The control circuitry is further configured to reduce the bit line voltage or the pass voltage for the verify operations in at least one subsequent program loop.
    Type: Application
    Filed: July 25, 2023
    Publication date: September 12, 2024
    Applicant: Western Digital Technologies, Inc.
    Inventors: Abhijith Prakash, Xiang Yang
  • Publication number: 20240304251
    Abstract: The memory device includes a quick pass write (QPW) voltage source and a transistor that can control the supply of a first QPW bias voltage to a plurality of bit lines. Control circuitry programs the memory cells of a selected word line in a plurality of program loops. For each memory cell in the selected word line, the control circuitry determines if the memory cell is within either a first or a second QPW zone. If the memory cell is in the second QPW zone, the control circuitry connects the QPW voltage source to the bit line that is in communication with that memory cell to supply the first QPW bias voltage to the bit line. In response to a determination that the memory cell is in the first QPW zone, the control circuitry controls the transistor to supply an average second QPW bias voltage to the bit line.
    Type: Application
    Filed: July 18, 2023
    Publication date: September 12, 2024
    Applicant: Western Digital Technologies, Inc.
    Inventors: Abhijith Prakash, Xiang Yang
  • Publication number: 20240296877
    Abstract: 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.
    Type: Application
    Filed: July 24, 2023
    Publication date: September 5, 2024
    Applicant: Western Digital Technologies, Inc.
    Inventors: Ke Zhang, Linnan Chen, Liang Li, Minna Li, Chin-Yi Chen, Xiaojia Jia, Muhammad Masuduzzaman, Xiang Yang
  • Patent number: 12079496
    Abstract: 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.
    Type: Grant
    Filed: September 1, 2022
    Date of Patent: September 3, 2024
    Assignee: SanDisk Technologies LLC
    Inventors: Chin-Yi Chen, Muhammad Masuduzzaman, Xiang Yang
  • Publication number: 20240290402
    Abstract: The memory device includes a memory block with memory cells arranged in word lines and control circuitry that is configured to program the memory cells in a selected word line to respective programmed data states in program loops, which each include verify operations. The control circuitry is further configured to lock out any of the memory cells in the selected word line memory cell from subsequent program pulses and verify operations in response to that memory cell passing verify for its respective programmed data state. For a selected programmed data state, the control circuitry is further configured to re-verify all of the memory cells in the selected word line that are being programmed to the selected programmed data state and release all memory cells that were locked out but fail re-verify in order to allow any memory cells that mistakenly passed verify to be programmed further.
    Type: Application
    Filed: July 19, 2023
    Publication date: August 29, 2024
    Applicant: Western Digital Technologies, Inc.
    Inventors: Abhijith Prakash, Xiang Yang
  • Publication number: 20240274200
    Abstract: 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.
    Type: Application
    Filed: July 24, 2023
    Publication date: August 15, 2024
    Applicant: SanDisk Technologies LLC
    Inventors: Chin-Yi Chen, Muhammad Masuduzzaman, Xiang Yang