Patents by Inventor Mohan Dunga

Mohan Dunga 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: 20260024584
    Abstract: A memory apparatus is disclosed herein. The memory apparatus includes memory cells each connected to one of a plurality of word lines and configured to retain a threshold voltage corresponding to one of a plurality of data states. The memory cells are disposed in memory holes defining channels. A control means is configured to generate holes by applying a hole pre-charge voltage to the channels of the memory holes in a pre-charge phase of a program operation of the memory cells in the memory holes. Following the pre-charge phase, the control means applies one of a series of programming pulses of a program voltage to selected ones of the plurality of word lines to program the memory cells connected thereto.
    Type: Application
    Filed: July 18, 2024
    Publication date: January 22, 2026
    Applicant: Sandisk Technologies, Inc.
    Inventors: Jiacen Guo, Qinghua Zhao, Mohan Dunga, Xiang Yang
  • Patent number: 12469555
    Abstract: A memory apparatus and method of operation are provided. The apparatus includes word line switches coupled to word lines connected to memory cells. The word line switches are each configured to retain a switch threshold voltage and selectively connect the word lines to a common driver for supplying voltages thereto during a memory operation. A control means is configured to apply predetermined select block switch voltages to a first set of the word line switches connected to the word lines of a selected block. The predetermined select block switch voltages are based on the memory operation performed. The control means apply a predetermined unselect block switch voltage to a second set of the word line switches connected to the word lines of an unselected block. The predetermined unselect block switch voltage is selected to lower the switch threshold voltage of the word line switches of the second set.
    Type: Grant
    Filed: July 31, 2023
    Date of Patent: November 11, 2025
    Assignee: Sandisk Technologies, Inc.
    Inventors: Mohan Dunga, Sudarshan Narayanan, Satoru Mayuzumi
  • Publication number: 20250259683
    Abstract: Embodiments disclosed herein are directed to a memory device, comprising a substrate including a word line switch well region; a non-volatile memory array including a plurality of memory strings of non-volatile storage elements arranged into rows and columns over the word line switch well region; a plurality of word lines, each word line is coupled to one or more rows of non-volatile storage elements; and control circuitry in communication with the non-volatile memory array. The control circuitry is configured to apply a negative voltage to the word line switch well region.
    Type: Application
    Filed: February 8, 2024
    Publication date: August 14, 2025
    Inventors: Mohan Dunga, Qinghua Zhao, Sudarshan Narayanan
  • Publication number: 20250259969
    Abstract: A non-volatile memory apparatus includes a stack of memory dies with multiple layers. Each layer has multiple memory die, and the stack includes separate parallel through silicon vias (TSVs) for each memory die. The non-volatile memory apparatus also includes a memory controller in electrical communication with the separate parallel TSVs for each memory die and configured to perform a high bandwidth read process for data stored in the stack across all or multiple of the memory dies.
    Type: Application
    Filed: June 10, 2024
    Publication date: August 14, 2025
    Inventors: Yan Li, James Kai, Mohan Dunga, Nagesh Vodrahalli
  • Publication number: 20250248041
    Abstract: A memory device includes memory blocks and a word line driver circuit including word line driver transistor pairs. Each of the memory blocks includes word line subblocks. Each of the word line driver transistor pairs includes a respective first word line driver transistor and a respective second word line driver transistor that share a common input node and having different respective first and second output nodes. A first subset of neighboring pairs of output nodes that are laterally spaced by a first portion of the dielectric isolation structure having a first width are electrically connected to word line zones within a same word line subblock, and a second subset of the neighboring pairs of output nodes that are laterally spaced by a second portion of the dielectric isolation structure having a second width greater than the first width are electrically connected to word lines within different word line subblocks.
    Type: Application
    Filed: July 26, 2024
    Publication date: July 31, 2025
    Inventors: Qinghua ZHAO, Mohan DUNGA
  • Publication number: 20250248040
    Abstract: A memory device includes a plurality of memory blocks including respective word lines; and a word line driver circuit including word line driver transistors. In one embodiment, the word line driver transistors are located in laterally offset rows. In another embodiment, at least one of a spacing between laterally adjacent word line driver transistors or a length of their source or drain region differs dependent on whether the transistors are connected to words lines in the same memory block or in different memory blocks.
    Type: Application
    Filed: January 26, 2024
    Publication date: July 31, 2025
    Inventors: Qinghua ZHAO, Sudarshan NARAYANAN, Mohan DUNGA, Hiroki YABE, Masahito TAKEHARA
  • Publication number: 20240386960
    Abstract: A memory apparatus and method of operation are provided. The apparatus includes word line switches coupled to word lines connected to memory cells. The word line switches are each configured to retain a switch threshold voltage and selectively connect the word lines to a common driver for supplying voltages thereto during a memory operation. A control means is configured to apply predetermined select block switch voltages to a first set of the word line switches connected to the word lines of a selected block. The predetermined select block switch voltages are based on the memory operation performed. The control means apply a predetermined unselect block switch voltage to a second set of the word line switches connected to the word lines of an unselected block. The predetermined unselect block switch voltage is selected to lower the switch threshold voltage of the word line switches of the second set.
    Type: Application
    Filed: July 31, 2023
    Publication date: November 21, 2024
    Applicant: Western Digital Technologies, Inc.
    Inventors: Mohan Dunga, Sudarshan Narayanan, Satoru Mayuzumi
  • Publication number: 20240387370
    Abstract: A semiconductor structure includes a memory die and a logic die. The memory die includes a three-dimensional memory device that contains an alternating stack of insulating layers and electrically conductive layers, memory openings vertically extending through the alternating stack, and memory opening fill structures located in the two-dimensional array of memory openings, where each of the memory opening fill structures includes a respective vertical semiconductor channel, a respective drain region, and a vertical stack of memory elements located at levels of the electrically conductive layers, memory-side bonding pads, and a first peripheral circuit including first thin film transistors located between the three-dimensional memory device and the memory-side bonding pads. The logic die includes a logic-side substrate, logic-side bonding pads bonded to the memory-side bonding pads, and a second peripheral circuit located between the logic-side substrate and the logic-side bonding pads.
    Type: Application
    Filed: July 28, 2023
    Publication date: November 21, 2024
    Inventors: Satoru MAYUZUMI, Sudarshan NARAYANAN, Mohan DUNGA
  • Publication number: 20240373633
    Abstract: A memory device includes an alternating stack of insulating layers and electrically conductive layers containing stepped surfaces in a contact region, a first stepped dielectric material portion overlying the stepped surfaces of the alternating stack, a memory opening vertically extending at least through each layer within the alternating stack, a memory opening fill structure located in the memory opening and containing a vertical stack of memory elements and a vertical semiconductor channel, and a bundled contact via structure vertically extending through the first stepped dielectric material portion and through a plurality of bottommost electrically conductive layers of the electrically conductive layers, and laterally contacting each of the plurality of the bottommost electrically conductive layers.
    Type: Application
    Filed: August 25, 2023
    Publication date: November 7, 2024
    Inventors: Mohan DUNGA, Koichi MATSUNO
  • Publication number: 20240371760
    Abstract: A semiconductor structure includes a logic die containing a word line switching circuit containing a fin field effect transistor having at least one semiconductor fin, and a planar field effect transistor, and a memory die containing a three-dimensional memory device bonded to the logic die.
    Type: Application
    Filed: July 28, 2023
    Publication date: November 7, 2024
    Inventors: Satoru MAYUZUMI, Sudarshan NARAYANAN, Mohan DUNGA
  • Patent number: 11508654
    Abstract: A non-volatile storage apparatus comprises a non-volatile memory structure and a plurality of I/O pads in communication with the non-volatile memory structure. The I/O pads include a power I/O pad, a ground I/O pad and data/control I/O pads. The non-volatile storage apparatus further comprises one or more capacitors connected to the power I/O pad and the ground I/O pad. The one or more capacitors are positioned in one or more metal interconnect layers below the signal lines and/or above device capacitors on the top surface of the substrate.
    Type: Grant
    Filed: May 28, 2020
    Date of Patent: November 22, 2022
    Assignee: SanDisk Technologies LLC
    Inventors: Luisa Lin, Mohan Dunga, Venkatesh P. Ramachandra, Peter Rabkin, Masaaki Higashitani
  • Patent number: 11444016
    Abstract: A non-volatile storage apparatus comprises a non-volatile memory structure and a plurality of I/O pads in communication with the non-volatile memory structure. The I/O pads include a power I/O pad, a ground I/O pad and data/control I/O pads. The non-volatile storage apparatus further comprises one or more capacitors connected to the power I/O pad and the ground I/O pad. The one or more capacitors are positioned in one or more metal interconnect layers below the signal lines and/or above device capacitors on the top surface of the substrate.
    Type: Grant
    Filed: May 28, 2020
    Date of Patent: September 13, 2022
    Assignee: SanDisk Technologes LLC
    Inventors: Luisa Lin, Mohan Dunga, Venkatesh P. Ramachandra, Peter Rabkin, Masaaki Higashitani
  • Patent number: 11404123
    Abstract: A non-volatile memory includes a non-volatile memory array comprising blocks of non-volatile memory cells, bit lines connected to the memory cells and word lines connected to the memory cells. Word line switch transistors connect the word lines to voltage sources. The word line switch transistors are positioned in triple wells. Multiple triple wells are utilized and the word line switch transistors are grouped into triple wells based on word line voltage ranges used during the programming process. In one embodiment, for a given block, the word line switch transistors connected to data word lines are positioned in a first triple well and the word line switch transistors connected to selection and dummy word lines are positioned in a second triple well. This structure allows the triple wells to be biased differently.
    Type: Grant
    Filed: April 15, 2021
    Date of Patent: August 2, 2022
    Assignee: SanDisk Technologies LLC
    Inventors: Shiqian Shao, Fumiaki Toyama, Yuki Mizutani, Mohan Dunga, Peter Rabkin
  • Patent number: 11251191
    Abstract: A three-dimensional memory device includes an alternating stack of insulating layers and electrically conductive layers located over a substrate, memory stack structures extending through the alternating stack, where each of the memory stack structures contains a respective memory film and a respective vertical semiconductor channel, drain regions contacting an upper end of a respective one of the vertical semiconductor channels, first contact via structures directly contacting a first subset of the drain regions and each having a first horizontal cross-sectional area, and second contact via structures directly contacting a second subset of the drain regions and each having a second horizontal cross-sectional area that is greater than the first horizontal cross-sectional area.
    Type: Grant
    Filed: December 24, 2018
    Date of Patent: February 15, 2022
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Lishan Weng, Fumiaki Toyama, Mohan Dunga
  • Patent number: 10984876
    Abstract: Various methods include receiving, by a controller, a temperature reading of a memory array, the temperature reading includes a temperature value; determining the temperature value is below a first threshold; in response, modifying a duration of a verify cycle of a write operation to create a modified verify cycle; then programming a first data into the memory array using the write operation that uses the modified verify cycle. Methods additionally include receiving a second temperature reading of the memory array, the second temperature reading includes a second temperature value; determining the second temperature value is below a second threshold, in response, decreasing the duration of a verify cycle of a verify cycle to create a second verify cycle, where the second verify cycle is shorter than the modified verify cycle; and then programming a second data into the memory array using the write operation that uses the second verify cycle.
    Type: Grant
    Filed: June 19, 2019
    Date of Patent: April 20, 2021
    Assignee: SanDiskTechnologies LLC
    Inventors: Piyush Dak, Mohan Dunga, Chao Qin, Muhammad Masuduzzaman, Xiang Yang
  • Patent number: 10978145
    Abstract: Apparatuses and techniques are provided for programming memory cells while reducing widening of a threshold voltage distribution due to changes in the temperature between the time of programming and the time of a subsequent read operation. One technique is based on a correlation between program speed and temperature coefficient (Tco). A different verify test is used for different memory cells which have a common assigned data state according to the program loop number and the temperature. Another technique is based on sensing the memory cells to measure their subthreshold slope and classifying the memory cells into groups. The sensing can occur as a separate operation before programming or as part of the programming of user data. The subsequent programming of the memory cells involves adjusting the verify test of each memory cell based on its group and the temperature.
    Type: Grant
    Filed: August 14, 2019
    Date of Patent: April 13, 2021
    Assignee: SanDisk Technologies LLC
    Inventors: Biswajit Ray, Peter Rabkin, Mohan Dunga, Gerrit Jan Hemink, Changyuan Chen
  • Patent number: 10971240
    Abstract: The storage device comprises a non-volatile memory coupled to a controller. The controller is configured to determine a first programming voltage by performing at least one program-verify iteration on a first word line using a voltage value which starts as a predetermined first initial voltage and is sequentially increased by a first voltage step amount following each failure to successfully program until the programming is completed. The controller is also configured to determine a second initial programming voltage by decreasing the first programming voltage by a second voltage step amount. The controller is further configured to perform at least one program-verify iteration on a second word line of the plurality of word lines using a voltage value which starts as the second initial programming voltage and is increased by the first voltage step amount following each sequential failure to successfully program until the programming is completed.
    Type: Grant
    Filed: December 24, 2019
    Date of Patent: April 6, 2021
    Inventors: Mohan Dunga, Pitamber Shukla
  • Publication number: 20210050054
    Abstract: Apparatuses and techniques are provided for programming memory cells while reducing widening of a threshold voltage distribution due to changes in the temperature between the time of programming and the time of a subsequent read operation. One technique is based on a correlation between program speed and temperature coefficient (Tco). A different verify test is used for different memory cells which have a common assigned data state according to the program loop number and the temperature. Another technique is based on sensing the memory cells to measure their subthreshold slope and classifying the memory cells into groups. The sensing can occur as a separate operation before programming or as part of the programming of user data. The subsequent programming of the memory cells involves adjusting the verify test of each memory cell based on its group and the temperature.
    Type: Application
    Filed: August 14, 2019
    Publication date: February 18, 2021
    Applicant: SanDisk Technologies LLC
    Inventors: Biswajit Ray, Peter Rabkin, Mohan Dunga, Gerrit Jan Hemink, Changyuan Chen
  • Patent number: 10878926
    Abstract: A high-performance write operation to program data to a group of non-volatile memory cells may be completed in response to applying a single programming pulse to the group. Programming of the cells may be verified (and/or corrected) after completion of the command. Verifying programming of the cells may comprise identifying under-programmed cells, and applying an additional programming pulse to the identified cells. The under-programmed cells may comprise cells within an under-program range below a target level. The under-program range may be determined based on a threshold voltage distribution of the cells in response to applying the single programming pulse.
    Type: Grant
    Filed: October 2, 2019
    Date of Patent: December 29, 2020
    Assignee: SanDisk Technologies LLC
    Inventors: Pitamber Shukla, Mohan Dunga, Anubhav Khandelwal
  • Publication number: 20200402594
    Abstract: Various methods include receiving, by a controller, a temperature reading of a memory array, the temperature reading includes a temperature value; determining the temperature value is below a first threshold; in response, modifying a duration of a verify cycle of a write operation to create a modified verify cycle; then programming a first data into the memory array using the write operation that uses the modified verify cycle. Methods additionally include receiving a second temperature reading of the memory array, the second temperature reading includes a second temperature value; determining the second temperature value is below a second threshold, in response, decreasing the duration of a verify cycle of a verify cycle to create a second verify cycle, where the second verify cycle is shorter than the modified verify cycle; and then programming a second data into the memory array using the write operation that uses the second verify cycle.
    Type: Application
    Filed: June 19, 2019
    Publication date: December 24, 2020
    Applicant: SanDisk Technologies LLC
    Inventors: Piyush Dak, Mohan Dunga, Chao Qin, Muhammad Masuduzzaman, Xiang Yang