Patents by Inventor Abu Naser Zainuddin

Abu Naser Zainuddin 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: 20240136001
    Abstract: A memory system programs memory cells connected to a selected word line by applying doses of programming and performing program-verify between doses. An efficient and low current program-verify operation includes: while scanning the results of a previous program-verify operation, ramp up voltages on the select lines for the next program-verify operation without waiting for the scan to complete and ramp up voltages on unselected word lines for the next program-verify operation following a step signal (so that voltage applied to the unselected word lines rise in steps) without waiting for the scan to complete.
    Type: Application
    Filed: July 23, 2023
    Publication date: April 25, 2024
    Applicant: SanDisk Technologies LLC
    Inventors: Abu Naser Zainuddin, Jiahui Yuan, Toru Miwa
  • Publication number: 20240127891
    Abstract: Technology is disclosed herein in which a duration of a program pulse used to program non-volatile memory cells such as NAND may be increased responsive to a programming failure using a shorter duration program pulse. The duration of at least one program pulse may be increased for at least one group of memory cells in response to a failure to program a group using a default program pulse duration. The group that experiences the increased duration program pulse may be the same group for which the program operation failed using the shorter program pulse or may be a different group than the group for which the program operation failed using the shorter program pulse.
    Type: Application
    Filed: July 21, 2023
    Publication date: April 18, 2024
    Applicant: SanDisk Technologies LLC
    Inventors: Abu Naser Zainuddin, Parth Amin, Xiaochen Zhu, Jiahui Yuan, Anubhav Khandelwal, Vishwanath Basavaegowda Shanthakumar
  • Publication number: 20240103742
    Abstract: In order to lower the peak and average current through the channel (thereby lowering peak and average power consumption) during program-verify, which exhibits a word line dependency, the inventors propose to program dummy memory cells connected to a dummy word line before programming data memory cells connected to a data word line. The additional resistance in the NAND string introduced by the preprogrammed dummy memory cells will cause the peak current, and power consumption, to be lower. To address the word line dependency, the dummy memory cells connected to the dummy word line can be programmed to different threshold voltages based on which data word line is to be programmed. Thus, prior to programming data non-volatile memory cells connected to a particular data word line, the dummy memory cells are programmed to a threshold voltage that is chosen based on the position of the particular data word line.
    Type: Application
    Filed: September 28, 2022
    Publication date: March 28, 2024
    Applicant: SanDisk Technologies LLC
    Inventors: Towhidur Razzak, Ravi Kumar, Abu Naser Zainuddin, Jiahui Yuan
  • Publication number: 20240071493
    Abstract: To reduce spikes in the current used by a NAND memory die, different ramp rates for different regions, or zones, of word lines are used for the pass voltage applied to unselected word lines during a program operation. The properties of the word lines, such as their resistance and capacitance (RC) values, vary across the NAND memory array. By determining the RC values of the word lines across the array, the word lines can be broken into multiple zones based on these properties. The zones can then be individually assigned different ramp rates for applying a pass voltage to the unselected word lines, where a parameter for the ramp rates can be stored as a register value on the memory die.
    Type: Application
    Filed: August 29, 2022
    Publication date: February 29, 2024
    Applicant: SanDisk Technologies LLC
    Inventors: Abu Naser Zainuddin, Jiahui Yuan, Towhidur Razzak
  • Publication number: 20240071544
    Abstract: To reduce spikes in the current used by a NAND memory die, different ramp rates are used for the pass voltage applied to unselected word lines during a program operation depending on whether data is stored in a multi-level cell (MLC) format or in a single level cell (SLC) format. These ramp rates can be determined through device characterization and stored as parameter values on the memory die. Different ramp rate interval values can also be used for the pass voltage applied to unselected word lines during a program operation depending on whether data is stored in an MLC format or in an SLC format.
    Type: Application
    Filed: August 29, 2022
    Publication date: February 29, 2024
    Applicant: SanDisk Technologies LLC
    Inventors: Abu Naser Zainuddin, Jiahui Yuan, Dong-il Moon
  • Patent number: 11875043
    Abstract: To reduce spikes in the current used by a NAND memory die during a write operation using smart verify, different amounts of delay are introduced into the loops of the programing algorithm. Depending on the number of verify levels following a programming pulse, differing amounts of wait time are used before biasing a selected word line to the verify levels or levels. For example, if only a single verify level is used, a shorter delay is used than if two verify levels are used.
    Type: Grant
    Filed: September 13, 2022
    Date of Patent: January 16, 2024
    Assignee: SanDisk Technologies LLC
    Inventors: Abu Naser Zainuddin, Jiahui Yuan, Toru Miwa
  • Patent number: 11705206
    Abstract: Apparatuses and techniques are described for modifying program and erase parameters in a memory device in which memory cells can be operated in a single bit per cell (SLC) mode or a multiple bits per cell mode. In one approach, the stress on a set of memory cells in an SLC mode is reduced during programming and erasing when the number of program-erase cycles for the block in the SLC mode is below a threshold. For example, during programming, the program-verify voltage and program voltages can be reduced to provide a shallower than normal programming. During erasing, the erase-verify voltage can be increased while the erase voltages can be reduced to provide a shallower than normal erase. When the number of program-erase cycles for the block in the SLC mode is above the threshold, the program and erase parameters revert to a default levels.
    Type: Grant
    Filed: August 17, 2021
    Date of Patent: July 18, 2023
    Assignee: SanDisk Technologies LLC
    Inventors: Abu Naser Zainuddin, Jia Li, Jiahui Yuan, Bo Lei
  • Publication number: 20230058038
    Abstract: Apparatuses and techniques are described for modifying program and erase parameters in a memory device in which memory cells can be operated in a single bit per cell (SLC) mode or a multiple bits per cell mode. In one approach, the stress on a set of memory cells in an SLC mode is reduced during programming and erasing when the number of program-erase cycles for the block in the SLC mode is below a threshold. For example, during programming, the program-verify voltage and program voltages can be reduced to provide a shallower than normal programming. During erasing, the erase-verify voltage can be increased while the erase voltages can be reduced to provide a shallower than normal erase. When the number of program-erase cycles for the block in the SLC mode is above the threshold, the program and erase parameters revert to a default levels.
    Type: Application
    Filed: August 17, 2021
    Publication date: February 23, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Abu Naser Zainuddin, Jia Li, Jiahui Yuan, Bo Lei
  • Patent number: 11475957
    Abstract: Apparatuses and techniques are described for optimizing programming in a memory device in which memory cells can be programmed using single bit per cell programming and multiple bits per cell programming. In one aspect, a single bit per cell program operation is performed which reduces damage to the memory cells as well as reducing program time. The program operation can omit a pre-charge phase and a verify phase of an initial program loop of a program operation. Instead, a program phase is performed followed by a recovery phase. In one or more subsequent program loops of the single bit per cell program operation, as well as in each program loop of a multiple bit per cell program operation, the program loop includes a pre-charge phase, a program phase, a recovery phase and a verify phase.
    Type: Grant
    Filed: January 14, 2021
    Date of Patent: October 18, 2022
    Assignee: SanDisk Technologies LLC
    Inventors: Abu Naser Zainuddin, Dongxiang Liao, Jiahui Yuan
  • Publication number: 20220223209
    Abstract: Apparatuses and techniques are described for optimizing programming in a memory device in which memory cells can be programmed using single bit per cell programming and multiple bits per cell programming. In one aspect, a single bit per cell program operation is performed which reduces damage to the memory cells as well as reducing program time. The program operation can omit a pre-charge phase and a verify phase of an initial program loop of a program operation. Instead, a program phase is performed followed by a recovery phase. In one or more subsequent program loops of the single bit per cell program operation, as well as in each program loop of a multiple bit per cell program operation, the program loop includes a pre-charge phase, a program phase, a recovery phase and a verify phase.
    Type: Application
    Filed: January 14, 2021
    Publication date: July 14, 2022
    Applicant: SanDisk Technologies LLC
    Inventors: Abu Naser Zainuddin, Dongxiang Liao, Jiahui Yuan
  • Patent number: 11205493
    Abstract: Apparatuses and techniques are described for reducing read disturb in a memory device by reducing the channel gradient and therefore reducing the charge injection to the memory cell. Channels of unselected NAND strings are boosted before reading memory cells in selected NAND strings. The boosting involves applying a positive voltage to source ends and drain ends of the unselected NAND strings, while drain-side select gate transistors are turned on and then off and a voltage signal of non-adjacent word lines of a selected word line, WLn, increases to a read pass voltage. A voltage signal of adjacent word lines of WLn is increased to a peak level to increase the channel conduction for faster read, where the peak level is less than the read pass voltage, decreased to a reduced level to reduce a channel gradient and therefore reduce a read disturb, then increased to the read pass voltage.
    Type: Grant
    Filed: October 26, 2020
    Date of Patent: December 21, 2021
    Assignee: SanDisk Technologies LLC
    Inventors: Abu Naser Zainuddin, Henry Chin, Jiahui Yuan
  • Patent number: 11139018
    Abstract: Apparatuses and techniques are described for reducing read time in a memory device. A source voltage signal, Vcelsrc, and a body voltage signal, Vp-well, of a source region and a p-well, respectively, of a substrate of a NAND string are controlled to reduce the channel resistance. Vcelsrc can be temporarily reduced, e.g., provided with a negative voltage kick, while Vp-well is non-decreasing during a read operation. The negative voltage kick decreases a body bias of the NAND string in its channel to reduce the channel resistance and increase the current. The negative voltage kick can be initiated when a bit line clamp transistor is made conductive to allow a current to flow in the NAND string. The magnitude and duration of the negative voltage kick can be adjusted based on various factors.
    Type: Grant
    Filed: August 31, 2020
    Date of Patent: October 5, 2021
    Assignee: SanDisk Technologies LLC
    Inventors: Abu Naser Zainuddin, Ohwon Kwon, Jiahui Yuan
  • Patent number: 10106892
    Abstract: Methods of forming conformal low temperature gate oxides on a HV I/O and a core logic and the resulting devices are provided. Embodiments include providing a HV I/O and core logic laterally separated on a Si substrate, each having a fin; forming a gate oxide layer over each fin and the Si substrate; forming a silicon oxy-nitride layer over the gate oxide layer; forming a sacrificial oxide layer over the silicon oxy-nitride layer; removing the sacrificial oxide and silicon oxy-nitride layers and thinning the gate oxide layer; forming a second gate oxide layer over the thinned gate oxide layer; forming a silicon oxy-nitride layer over the second gate oxide layer; removing the silicon oxy-nitride and second gate oxide layers over the core logic fin portion; forming an IL over the core logic fin portion; and forming a HfOx layer over the second silicon oxy-nitride layer and ILs.
    Type: Grant
    Filed: August 31, 2017
    Date of Patent: October 23, 2018
    Assignee: GLOBALFOUNDRIES INC.
    Inventors: Shahab Siddiqui, Abu Naser Zainuddin, Beth Baumert, Suresh Uppal