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).

  • Patent number: 11625172
    Abstract: Apparatuses and techniques are described for programming data in memory cells while concurrently storing backup data. One or more initial pages of data are programmed into both a primary block and a first backup block in a first program pass. A power loss then occurs which can corrupt the data or otherwise prevent reading of the one or more initial pages of data from the primary block. The one or more initial pages of data are read from the first backup block and used to perform a second program pass in which one or more additional pages of data are programmed into the primary block. Single bit per cell data can be stored in a second backup block to decode the one or more initial pages of data as read from the first backup block.
    Type: Grant
    Filed: June 16, 2021
    Date of Patent: April 11, 2023
    Assignee: SanDisk Technologies LLC
    Inventors: Xiang Yang, Toru Miwa, Ken Oowada, Gerrit Jan Hemink
  • Patent number: 11621045
    Abstract: An apparatus is described. The apparatus includes a non volatile memory chip. The non volatile memory chip includes an interface to receive access commands, a three dimensional array of non volatile storage cells, and, a controller to orchestrate removal of charge in a column of stacked ones of the non volatile storage cells after a verification process that determined whether or not a particular cell along the column was programmed with a correct charge amount. The removal of the charge pushes the charge out of the column by changing respective word line potentials along a particular direction along the column. Cells that are coupled to the column are programmed in the particular direction. Disturbance of neighboring cells during programming is less along the particular direction than a direction opposite that of the particular direction.
    Type: Grant
    Filed: March 4, 2020
    Date of Patent: April 4, 2023
    Assignee: Intel Corporation
    Inventor: Xiang Yang
  • Publication number: 20230101019
    Abstract: Technology for mitigating interference to select transistors in 3D memory is disclosed. In one aspect, a control circuit pre-charges a first set of bit lines to a first voltage and pre-charges a second set of bit lines to a second voltage greater than the first voltage. The control circuit may increase the voltage on the first set of bit lines to the second voltage while the second set of bit lines are floating to couple up the voltages on the second set of bit lines to a voltage greater than the second voltage. The higher voltage on the second set of bit lines compensates for interference that some of the select transistors may experience from an adjacent select line. For example, the higher voltage can prevent a leakage current in the select transistors from occurring. Preventing the leakage current can improve boosting of NAND channel voltages, thereby preventing program disturb.
    Type: Application
    Filed: September 24, 2021
    Publication date: March 30, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Xiang Yang, Kou Tei, Ohwon Kwon
  • Publication number: 20230095757
    Abstract: A method of operating a memory device. The method includes the step of preparing a memory device that includes a first group of the memory holes with full SGD transistors and a second group of the memory holes with partial SGD transistors. The second group includes both a set of selected partial SGD transistors and a set of unselected partial SGD transistors. The method proceeds with electrically floating a first unselected partial SGD transistor of the set of unselected partial SGD transistors. With the at least one first unselected partial SGD transistor electrically floating, the method continues with reducing a voltage applied to at least one transistor or memory cell adjacent the first unselected partial SGD transistor such that a voltage of the first unselected partial SGD transistor is decreased through a capacitance coupling effect.
    Type: Application
    Filed: September 28, 2021
    Publication date: March 30, 2023
    Applicant: SanDisk Technologies LLC
    Inventor: Xiang Yang
  • Publication number: 20230097040
    Abstract: A memory apparatus and method of operation are provided. The apparatus includes memory cells connected to word lines and arranged in strings. The memory cells are configured to retain a threshold voltage corresponding to memory states. Each one of the strings has drain-side select gate transistors on a drain-side of the one of the strings including top drain-side select gate transistors connected to bit lines and coupled to the memory cells of the-one of the strings. A control means is coupled to the word lines and bit lines and is configured to apply an unselected top voltage to unselected ones of the top drain-side select gate transistors during a memory operation. The control means is also configured to simultaneously apply a selected top voltage to selected ones top drain-side select gate transistors during the memory operation. The unselected top voltage is intentionally different electrically than the selected top voltage.
    Type: Application
    Filed: September 28, 2021
    Publication date: March 30, 2023
    Applicant: SanDisk Technologies LLC
    Inventor: Xiang Yang
  • Publication number: 20230102668
    Abstract: A memory apparatus and method of operation are provided. The apparatus includes memory cells connected to one of a plurality of word lines including at least one edge word line and a plurality of other data word lines. The memory cells are arranged in strings and configured to retain a threshold voltage corresponding to one of a plurality of data states. The memory apparatus also includes a control means coupled to the plurality of word lines and the strings. The control means is configured to identify the at least one edge word line. The control means is also configured to periodically apply a program voltage to the at least one edge word line to reprogram the memory cells associated with the at least one edge word line without erasing the memory cells associated with the at least one edge word line.
    Type: Application
    Filed: September 28, 2021
    Publication date: March 30, 2023
    Applicant: SanDisk Technologies LLC.
    Inventor: Xiang Yang
  • Patent number: 11615839
    Abstract: In a three dimensional non-volatile memory structure that etches part of the top of the memory structure (including a portion of the select gates), data is stored on a majority (or all but one) of the word lines as x bits per memory cell while data is stored on a top edge word line that is closest to the etching with variable bits per memory cell. In one example embodiment that implements vertical NAND strings, memory cells connected to the top edge word line and that are on NAND strings adjacent the etching store data as n bits per memory cell and memory cells connected to the top edge word line and that are on NAND strings not adjacent the etching store data as m bits per memory cell, where m>x>n.
    Type: Grant
    Filed: July 6, 2021
    Date of Patent: March 28, 2023
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventor: Xiang Yang
  • Publication number: 20230076245
    Abstract: An apparatus includes a control circuit configured to connect to first word lines of a first vertical sub-block and second word lines of a second vertical sub-block. The first vertical sub-block and the second vertical sub-block include memory cells connected in series in NAND strings, each NAND string including memory cells coupled to the first word lines in series with memory cells connected to the second word lines. The control circuit is configured to program or sense memory cells along a selected first word line of the first vertical sub-block while applying a first voltage to second word lines that are connected to programmed memory cells and applying a second voltage to second word lines that are connected to unprogrammed memory cells.
    Type: Application
    Filed: September 8, 2021
    Publication date: March 9, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Xiang Yang, Deepanshu Dutta, Gerrit Jan Hemink
  • Publication number: 20230053269
    Abstract: A storage device that includes a non-volatile memory with a control circuitry is provided. The control circuitry is communicatively coupled to a memory block that includes an array of memory cells. The control circuitry is configured to program one or more bits of data into the memory cells. The control circuitry is further configured to operate the non-volatile memory in a multi-bit per memory cell mode, monitor a usage metric while the non-volatile memory is operating in the multi-bit per memory cell mode, and determine if the usage metric has crossed a predetermined threshold. In response to the usage metric not crossing the predetermined threshold, the control circuitry continues to operate the non-volatile memory in the multi-bit per memory cell mode. In response to the usage metric crossing the predetermined threshold, the control circuitry automatically operates the non-volatile memory in a single-bit per memory cell mode.
    Type: Application
    Filed: August 16, 2021
    Publication date: February 16, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Xiang Yang, Masaaki Higanshitani, Abhijith Prakash
  • Publication number: 20230046677
    Abstract: A memory apparatus and method of operation are provided. The apparatus includes apparatus including memory cells connected to word lines including at least one dummy word line and data word lines. The memory cells are arranged in strings and are configured to retain a threshold voltage. The apparatus also includes a control means coupled to the word lines and the strings and configured to identify ones of the memory cells connected to the at least one dummy word line with the threshold voltage being below a predetermined detection voltage threshold following an erase operation. The control means is also configured to selectively apply at least one programming pulse of a maintenance program voltage to the at least one dummy word line to program the ones of the memory cells connected to the at least one dummy word line having the threshold voltage being below the predetermined detection voltage threshold.
    Type: Application
    Filed: August 10, 2021
    Publication date: February 16, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Xiang Yang, Deepanshu Dutta, Gerrit Jan Hemink, Shubhajit Mukherjee
  • Publication number: 20230052121
    Abstract: A storage device that includes a non-volatile memory is provided. The non-volatile memory includes a control circuitry that is communicatively coupled to a memory block that includes memory cells arranged word lines. The control circuitry is configured to program the memory cells of a selected word line in a plurality of programming loops to store a single bit of data in each memory cell of the selected word line. The programming loops include programming operations and verify operations. The programming operations include applying a programming voltage to the selected word line, and the verify operations include applying a verify voltage to the selected word line. At least one programming loop of the plurality of programming loops further includes a pre-verify operation. The pre-verify operation includes applying a pre-read voltage to the selected word line. The pre-read voltage is less than the verify voltage.
    Type: Application
    Filed: August 16, 2021
    Publication date: February 16, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Xiang Yang, Masaaki Higanshitani
  • Publication number: 20230050955
    Abstract: To help reduce program disturbs in non-selected NAND strings of a non-volatile memory, a sub-block based boosting scheme in introduced. For a three dimensional NAND memory structure, in which the memory cells above a joint region form an upper sub-block and memory cells below the joint region form a lower sub-block, dummy word lines in the joint region act as select gates to allow boosting at the sub-block level when the lower block is being programmed in a reverse order.
    Type: Application
    Filed: August 11, 2021
    Publication date: February 16, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Dengtao Zhao, Gerrit Jan Hemink, Xiang Yang, Ken Oowada, Guirong Liang
  • Publication number: 20230041476
    Abstract: Technology is provided for extending the useful life of a block of memory cells by changing an operating parameter in a physical region of the block that is more susceptible to wear than other regions. Changing the operating parameter in the physical region extends the life of that region, which extends the life of the block. The operating parameter may be, for example, a program voltage step size or a storage capacity of the memory cells. For example, using a smaller program voltage step size in a sub-block that is more susceptible to wear extends the life of that sub-block, which extends the life of the block. For example, programming memory cells to fewer bits per cell in the region of the block (e.g., sub-block, word line) that is more susceptible to wear extends the useful life of that region, which extends the life of the block.
    Type: Application
    Filed: August 3, 2021
    Publication date: February 9, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Xiang Yang, Peter Rabkin, Henry Chin, Ken Oowada, Dengtao Zhao, Gerrit Jan Hemink
  • Patent number: 11562800
    Abstract: This disclosure proposes a method to save P/E cycling information inside NAND by using 2-byte column in programmable selective devices (e.g., SGD). The proposed method is a one-way programming method, and does not perform an erase operation within the 2-byte column. The proposed methods described herein can reduce the burden of relying upon controller SRAM/DRAM. Additionally, by storing the P/E cycling information in NAND, the P/E cycling is not lost due to a power loss event. At least one application advantageous for using NAND to store P/E cycling information includes wear leveling.
    Type: Grant
    Filed: June 9, 2021
    Date of Patent: January 24, 2023
    Assignee: SanDisk Technologies LLC
    Inventor: Xiang Yang
  • Publication number: 20230012977
    Abstract: In a three dimensional non-volatile memory structure that etches part of the top of the memory structure (including a portion of the select gates), data is stored on a majority (or all but one) of the word lines as x bits per memory cell while data is stored on a top edge word line that is closest to the etching with variable bits per memory cell. In one example embodiment that implements vertical NAND strings, memory cells connected to the top edge word line and that are on NAND strings adjacent the etching store data as n bits per memory cell and memory cells connected to the top edge word line and that are on NAND strings not adjacent the etching store data as m bits per memory cell, where m>x>n.
    Type: Application
    Filed: July 6, 2021
    Publication date: January 19, 2023
    Applicant: SANDISK TECHNOLOGIES LLC
    Inventor: Xiang Yang
  • Patent number: 11551761
    Abstract: In a non-volatile memory, a block of NAND strings is divided into sub-blocks by etching the select gate layers between sub-blocks. This results in a subset of NAND strings (e.g., at the border of the sub-blocks) having select gates that are partially etched such that the partially etched select gates are partially shaped as compared to the select gates of NAND strings that have not been etched. Host data is programmed to non-volatile memory cells that are connected to an edge word line and are on NAND strings having a complete shaped select gate. Host data is also programmed to non-volatile memory cells that are connected to non-edge word lines. However, host data is not programmed to non-volatile memory cells that are connected to the edge word line and are on NAND strings having a partial shaped select gate.
    Type: Grant
    Filed: August 30, 2021
    Date of Patent: January 10, 2023
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Xiang Yang, Deepanshu Dutta
  • Patent number: 11551765
    Abstract: A non-volatile memory system adjusts the speed of a memory operation for a subset of non-volatile memory cells. For example, during a GIDL based erase process, the GIDL generation can be dampened for a subset of memory cells (e.g., for a set of NAND strings, or one or more sub-blocks).
    Type: Grant
    Filed: May 25, 2021
    Date of Patent: January 10, 2023
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Xiang Yang, Dengtao Zhao
  • Patent number: 11551781
    Abstract: Apparatuses and techniques are described for programming data in memory cells while concurrently storing backup data. Initial pages of multiple bit per cell data are encoded to obtain at least first and second pages of single bit per cell data. The initial pages of multiple bit per cell data are programmed into a primary set of memory cells, while concurrently the first and second pages of single bit per cell data are programmed into first and second backup sets of memory cells, respectively. In the event of a power loss, the first and second pages of single bit per cell data are read from the first and second backup sets of memory cells, and decoded to recover the initial pages of multiple bit per cell data.
    Type: Grant
    Filed: June 16, 2021
    Date of Patent: January 10, 2023
    Assignee: SanDisk Technologies LLC
    Inventors: Xiang Yang, Toru Miwa, Ken Oowada, Gerrit Jan Hemink
  • Patent number: 11545226
    Abstract: Non-volatile memory systems are disclosed. The memory systems include rows of memory holes FC-SGD and SC-SGD, the latter of which may be created by a SHE cutting operation. The SC-SGD include erase speeds slower than those of FC-SGD. In order to overcome the erase speed disparities, SC-SGD are programmed to a higher Vt as compared to FC-SGD. By programming SC-SGD to a higher Vt, the erase speed increases and matches the erase speed of FC-SGD. Further, different SC-SGDs are cut to different amounts, creating different erase speeds among SC-SGD. SC-SGDs with a greater degree/amount of cut have slower erase speeds as compared to SC-SGDs with a lesser degree/amount of cut. However, verify levels among SC-SGDs can differ to produce SC-SGDs with Vt's such that their erase speeds match with each other as well as with FC-SGD.
    Type: Grant
    Filed: June 23, 2021
    Date of Patent: January 3, 2023
    Assignee: SanDisk Technologies LLC
    Inventors: Abhijith Prakash, Xiang Yang
  • Patent number: 11545221
    Abstract: Technology is disclosed herein for concurrently programming the same data pattern in multiple sets of non-volatile memory cells. Voltage are applied to bit lines in accordance with a data pattern. A select voltage is applied to drain select gates of multiple sets of NAND strings. The system concurrently applies a program pulse to control gates of a different set of selected memory cells in each respective set of the multiple sets of the NAND strings while the select voltage is applied to the drain select gates of the multiple sets of the NAND strings and the voltages are applied to the plurality of bit lines to concurrently program the data pattern into each set of the selected memory cells.
    Type: Grant
    Filed: June 28, 2021
    Date of Patent: January 3, 2023
    Assignee: SanDisk Technologies LLC
    Inventors: Xiang Yang, Gerrit Jan Hemink, Ken Oowada, Toru Miwa