Patents by Inventor Jiacen Guo

Jiacen Guo 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: 20240145006
    Abstract: Memory cells of a second sub-block are programmed by pre-charging channels of unselected memory cells connected to the selected word line, boosting the pre-charged channels of unselected memory cells and applying a program voltage to selected non-volatile memory cells connected to the selected word line. The pre-charging includes applying one or more overdrive voltages to word lines connected to memory cells of a first sub-block to provide a conductive path from memory cells of the second sub-block through the first sub-block to a source line and maintaining the word lines connected to memory cells of the first sub-block at one or more overdrive voltages while ramping down signals at the end of the pre-charging. Dummy word lines, positioned between sub-blocks, are maintained at a resting voltage during the boosting in order to cut-off channels of memory cells in the second sub-block from channels of memory cells in the first sub-block.
    Type: Application
    Filed: July 24, 2023
    Publication date: May 2, 2024
    Applicant: SanDisk Technologies LLC
    Inventors: Peng Zhang, Yanli Zhang, Dengtao Zhao, Jiacen Guo
  • Patent number: 11972820
    Abstract: Memory cells are arranged as NAND strings to form a block divided into sub-blocks, and each NAND string includes a dummy memory cell connected to a dummy word line. Memory cells are programmed by applying programming pulses to a selected word line in a selected sub-block with program-verify performed between pulses. Unselected NAND strings are inhibited from programming by boosting channels of the unselected NAND strings in the selected sub-block from a positive pre-charge voltage to a boosted voltage. The pre-charging of the channels of unselected NAND strings is performed while lowering voltages at the end of program-verify by applying overdrive voltages to data word lines in a sub-block closer to the source line than the selected sub-block and lowering to a resting voltage a dummy word line between the sub-blocks prior to lowering to a resting voltage the data word lines in the sub-block closer to the source line.
    Type: Grant
    Filed: August 30, 2022
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies LLC
    Inventors: Jiacen Guo, Dengtao Zhao, Xiang Yang
  • Patent number: 11972813
    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.
    Type: Grant
    Filed: December 20, 2021
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies, LLC
    Inventors: Jiacen Guo, Xiang Yang, Swaroop Kaza, Laidong Wang
  • Patent number: 11972819
    Abstract: In a non-volatile memory system that performs programming of selected memory cells (in coordination with pre-charging and boosting of channels for unselected memory cells) and program-verify to determine whether the programming was successful, the system transitions from program-verify to the next dose of programming by concurrently lowering a voltage applied to a selected word line and voltages applied to word lines on a first side of the selected word line at the conclusion of program-verify. Subsequent to lowering the voltage applied to the selected word line, the system successively lowers voltages applied to groups of one or more word lines on a second side of the selected word line at the conclusion of program-verify beginning with a group of one or more word lines immediately adjacent the selected word line and progressing to other groups of one or more word lines disposed increasingly remote from the selected word line.
    Type: Grant
    Filed: July 25, 2022
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies LLC
    Inventors: Jiacen Guo, Peng Zhang, Xiang Yang, Yanli Zhang
  • Patent number: 11972806
    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.
    Type: Grant
    Filed: June 10, 2022
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies, LLC
    Inventors: Jiacen Guo, Xiang Yang
  • Patent number: 11955184
    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.
    Type: Grant
    Filed: May 10, 2022
    Date of Patent: April 9, 2024
    Assignee: SanDisk Technologies LLC
    Inventors: Jiacen Guo, Xiaochen Zhu, Xiang Yang, Lito De La Rama, Yi Song, Jiahui Yuan
  • Publication number: 20240112735
    Abstract: In a multi-tiered non-volatile memory structure that can perform operations on sub-blocks, performance of the different tiers/sub-blocks is made consistent by using different word line to word line pitches in the different tiers/sub-blocks.
    Type: Application
    Filed: September 29, 2022
    Publication date: April 4, 2024
    Applicant: SanDisk Technologies LLC
    Inventors: Xiang Yang, Wei Cao, Jiacen Guo
  • Patent number: 11942157
    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.
    Type: Grant
    Filed: March 17, 2022
    Date of Patent: March 26, 2024
    Assignee: SanDisk Technologies LLC
    Inventors: Jiacen Guo, Xiang Yang, Xiaochen Zhu
  • Publication number: 20240079062
    Abstract: The memory device includes at least one memory block with source and drain sides and a plurality of memory cells arranged in a plurality of word lines. The word lines are arranged in a plurality of independently programmable and erasable sub-blocks. Control circuitry is configured to program the memory cells of a selected sub-block and determine a location of the within the at least one memory block and determine a programming condition of at least one unselected sub-block. The control circuitry is also configured to program at least one word line in the selected sub-block in a plurality of program loops that include pre-charging processes. The control circuitry pre-charges a plurality of channels from either the source or drain side based on at least one of the location of the selected sub-block within the memory block and the programming condition of the at least one unselected sub-block.
    Type: Application
    Filed: September 6, 2022
    Publication date: March 7, 2024
    Applicant: SanDisk Technologies LLC
    Inventors: Jiacen Guo, Han-Ping Chen, Henry Chin, Guirong Liang, Xiang Yang
  • Patent number: 11923019
    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.
    Type: Grant
    Filed: February 14, 2022
    Date of Patent: March 5, 2024
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Xiaojia Jia, Swaroop Kaza, Laidong Wang, Jiacen Guo
  • Publication number: 20240071509
    Abstract: The techniques include a memory device receiving a data write instruction. The memory device programs the memory cells of the memory blocks to a one bit per memory cell (SLC) format with a first and second SLC data states. In response to the data programmed to the memory cells of the memory blocks reaching an SLC limit prior to completion of the data write instruction, without erasing the memory cells, the memory device programs at least some of the memory cells from the SLC format to a two bits per memory cell (MLC) format. When programming from the SLC format to the MLC format, the memory device inhibits programming of some of the memory cells in the first and second SLC data states to form a first MLC data state and programs other memory cells of the SLC data states to form second, third, and fourth MLC data states.
    Type: Application
    Filed: August 29, 2022
    Publication date: February 29, 2024
    Applicant: SanDisk Technologies LLC
    Inventors: Xiang Yang, Jiacen Guo, Shubhajit Mukherjee
  • Publication number: 20240071529
    Abstract: Memory cells are arranged as NAND strings to form a block divided into sub-blocks, and each NAND string includes a dummy memory cell connected to a dummy word line. Memory cells are programmed by applying programming pulses to a selected word line in a selected sub-block with program-verify performed between pulses. Unselected NAND strings are inhibited from programming by boosting channels of the unselected NAND strings in the selected sub-block from a positive pre-charge voltage to a boosted voltage. The pre-charging of the channels of unselected NAND strings is performed while lowering voltages at the end of program-verify by applying overdrive voltages to data word lines in a sub-block closer to the source line than the selected sub-block and lowering to a resting voltage a dummy word line between the sub-blocks prior to lowering to a resting voltage the data word lines in the sub-block closer to the source line.
    Type: Application
    Filed: August 30, 2022
    Publication date: February 29, 2024
    Applicant: SanDisk Technologies LLC
    Inventors: Jiacen Guo, Dengtao Zhao, Xiang Yang
  • Publication number: 20240071508
    Abstract: The memory device includes a plurality of memory blocks, each including a plurality of memory cells arranged in a plurality of word lines. Control circuitry is in communication with the plurality of memory blocks. In operation, the control circuitry receives a data write instruction and programs the memory cells of the memory blocks to a one bit per memory cell (SLC) format. In response to the data programmed to the memory cells of the memory blocks in the SLC format reaching an SLC limit prior to completion of the data write instruction, without erasing the memory cells programmed to the SLC format, the control circuitry programs the memory cells of at least some of the plurality of memory blocks from the SLC format to a two bits per memory cell (MLC) format.
    Type: Application
    Filed: August 26, 2022
    Publication date: February 29, 2024
    Applicant: SanDisk Technologies LLC
    Inventors: Xiang Yang, Jiacen Guo, Takayuki Inoue
  • Publication number: 20240055059
    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: Application
    Filed: August 10, 2022
    Publication date: February 15, 2024
    Applicant: SanDisk Technologies LLC
    Inventors: Jiacen Guo, Dengtao Zhao, Xiang Yang
  • Patent number: 11901016
    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).
    Type: Grant
    Filed: April 29, 2022
    Date of Patent: February 13, 2024
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Xiaojia Jia, Jiacen Guo
  • Patent number: 11894072
    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.
    Type: Grant
    Filed: April 20, 2022
    Date of Patent: February 6, 2024
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Jiacen Guo, Xiang Yang, Abhijith Prakash
  • Publication number: 20240029806
    Abstract: In a non-volatile memory system that performs programming of selected memory cells (in coordination with pre-charging and boosting of channels for unselected memory cells) and program-verify to determine whether the programming was successful, the system transitions from program-verify to the next dose of programming by concurrently lowering a voltage applied to a selected word line and voltages applied to word lines on a first side of the selected word line at the conclusion of program-verify. Subsequent to lowering the voltage applied to the selected word line, the system successively lowers voltages applied to groups of one or more word lines on a second side of the selected word line at the conclusion of program-verify beginning with a group of one or more word lines immediately adjacent the selected word line and progressing to other groups of one or more word lines disposed increasingly remote from the selected word line.
    Type: Application
    Filed: July 25, 2022
    Publication date: January 25, 2024
    Applicant: SanDisk Technologies LLC
    Inventors: Jiacen Guo, Peng Zhang, Xiang Yang, Yanli Zhang
  • Patent number: 11881271
    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.
    Type: Grant
    Filed: May 31, 2022
    Date of Patent: January 23, 2024
    Assignee: SanDisk Technologies LLC
    Inventors: Jiacen Guo, Xiang Yang, Xiaochen Zhu
  • Publication number: 20240006002
    Abstract: To remedy short term data retention issues, a system creates a gate to channel voltage differential for non-volatile memory cells between programming and verifying in order to accelerate the effects of the short term data retention issue. That is, the gate to channel voltage differential will accelerate the migrating of electrons out of shallow traps. In some embodiments, the gate to channel voltage differential comprises a higher voltage at the channel in comparison to the gate. In some embodiments, the programming comprises applying doses of a programming signal and the gate to channel voltage differential is only created for a subset of the time periods between doses of the programming signal.
    Type: Application
    Filed: June 29, 2022
    Publication date: January 4, 2024
    Applicant: SanDisk Technologies LLC
    Inventors: Yi Song, Jiacen Guo, Jiahui Yuan
  • Patent number: 11862249
    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.
    Type: Grant
    Filed: November 16, 2021
    Date of Patent: January 2, 2024
    Assignee: SanDisk Technologies LLC
    Inventors: Xiang Yang, Fanqi Wu, Jiacen Guo, Jiahui Yuan