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: 20200194094
    Abstract: Recovering data from a faulty memory block in a memory system. Various methods include: reading a target word line in a memory block to obtain a first data; determining the first data has an uncorrectable error; and then adjust bias parameters of a first group of neighboring word lines within the memory block, where adjusting bias parameters creates a first adjusted bias parameters; and reading the target word line using the adjusted bias parameters to obtain second data from the target word line. The method also includes determining the second data has a second uncorrectable error; and then adjusting bias parameters of a second group of lines within the memory block, where adjusting the bias parameters of the second group creates second adjusted bias parameters; and reading the target word line using the first and second adjusted bias parameters to obtain a third data from the target word line.
    Type: Application
    Filed: December 17, 2018
    Publication date: June 18, 2020
    Inventors: Niles Yang, Pitamber Shukla, Mohan Dunga
  • Patent number: 10643695
    Abstract: A sense amplifier for a memory circuit that can sense into the deep negative voltage threshold region is described. A selected memory cell is sensed by discharging a source line through the memory cell into the bit line and sense amplifier. While discharging the source line through the memory cell into the sense amplifier, a voltage level on the discharge path is used to set the conductivity of a discharge transistor to a level corresponding to the conductivity of the selected memory cell. A sense node is then discharged through the discharge transistor. By allowing the sense amplifier to bias a memory cell being sensed to a selected one of multiple bias levels during a sensing operation, multiple target data states can be concurrently program verified, leading to higher performance when writing data.
    Type: Grant
    Filed: January 10, 2019
    Date of Patent: May 5, 2020
    Assignee: SanDisk Technologies LLC
    Inventors: Hao Nguyen, Chia-kai Chou, Mohan Dunga
  • Patent number: 10559370
    Abstract: A circuit includes a detection circuit configured to determine a capacitance delay (RC-delay) in an initial stage of a read or program operation and to adjust timing for detecting data in a subsequent stage, or portion of a stage, of the same read or programming operation. In particular, during a program operation a detection circuit may be configured to detect a pre-charge time for a bit line and adjust a timing of subsequent verify stages of the bit line during the same program operation based on the detected pre-charge time. Additionally, a word line circuit may be configured to detect a pre-charge time for a word line during an initial stage of a read operation and adjust read timing for a subsequent portion of the same read stage, or subsequent read stage of the read operation based on the detected word line pre-charge time.
    Type: Grant
    Filed: March 22, 2018
    Date of Patent: February 11, 2020
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Xiang Yang, Piyush Dak, Wei Zhao, Huai-Yuan Tseng, Deepanshu Dutta, Mohan Dunga
  • Publication number: 20200035313
    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: Application
    Filed: October 2, 2019
    Publication date: January 30, 2020
    Inventors: Pitamber Shukla, Mohan Dunga, Anubhav Khandelwal
  • Patent number: 10535411
    Abstract: Systems and methods for string-based erase verify to create partial good blocks are disclosed. A block in non-volatile flash memory may include multiple strings. In practice, one string may be slower to erase than other strings. In analyzing the strings, the memory device may iteratively analyze the strings to verify as erased. As one example, the iterations are modified by changing which strings are erased in the subsequent iterations (e.g., only the strings that fail the erase verify). As another example, a predetermined number of iterations are performed after a majority of the strings are verified as erased. In this way, the strings verified as erased need not undergo more deep erasing, which may damage the strings. Further, if fewer than all of the strings are verified as erased, the memory device may designate the block as a partially good block.
    Type: Grant
    Filed: May 26, 2017
    Date of Patent: January 14, 2020
    Assignee: Western Digital Technologies, Inc.
    Inventors: Mohan Dunga, Anubhav Khandelwal, Changyuan Chen, Biswajit Ray
  • Publication number: 20200013434
    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. The one or more capacitors are positioned in one or more metal interconnect layers below the I/O pads.
    Type: Application
    Filed: October 23, 2018
    Publication date: January 9, 2020
    Applicant: SANDISK TECHNOLOGIES LLC
    Inventors: Luisa Lin, Mohan Dunga, Venkatesh P. Ramachandra, Peter Rabkin, Masaaki Higashitani
  • Publication number: 20200013794
    Abstract: A non-volatile storage apparatus comprises a non-volatile memory structure and an I/O interface. A portion of the memory die is used as a pool capacitor for the I/O interface.
    Type: Application
    Filed: September 25, 2018
    Publication date: January 9, 2020
    Applicant: SANDISK TECHNOLOGIES LLC
    Inventors: Mohan Dunga, James Kai, Venkatesh P. Ramachandra, Piyush Dak, Luisa Lin, Masaaki Higashitani
  • Publication number: 20200013795
    Abstract: A non-volatile storage apparatus comprises a non-volatile memory structure and an I/O interface. A portion of the memory die is used as a pool capacitor for the I/O interface.
    Type: Application
    Filed: September 25, 2018
    Publication date: January 9, 2020
    Applicant: SANDISK TECHNOLOGIES LLC
    Inventors: Mohan Dunga, James Kai, Venkatesh P. Ramachandra, Piyush Dak, Luisa Lin, Masaaki Higashitani
  • Publication number: 20200013714
    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: Application
    Filed: October 23, 2018
    Publication date: January 9, 2020
    Applicant: SANDISK TECHNOLOGIES LLC
    Inventors: Luisa Lin, Mohan Dunga, Venkatesh P. Ramachandra, Peter Rabkin, Masaaki Higashitani
  • Patent number: 10460816
    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: April 30, 2018
    Date of Patent: October 29, 2019
    Assignee: Sandisk Technologies LLC
    Inventors: Pitamber Shukla, Mohan Dunga, Anubhav Khandelwal
  • Publication number: 20190295669
    Abstract: A circuit includes a detection circuit configured to determine a capacitance delay (RC-delay) in an initial stage of a read or program operation and to adjust timing for detecting data in a subsequent stage, or portion of a stage, of the same read or programing operation. In particular, during a program operation a detection circuit may be configured to detect a pre-charge time for a bit line and adjust a timing of subsequent verify stages of the bit line during the same program operation based on the detected pre-charge time. Additionally, a word line circuit may be configured to detect a pre-charge time for a word line during an initial stage of a read operation and adjust read timing for a subsequent portion of the same read stage, or subsequent read stage of the read operation based on the detected word line pre-charge time.
    Type: Application
    Filed: March 22, 2018
    Publication date: September 26, 2019
    Applicant: SanDisk Technologies LLC
    Inventors: Xiang Yang, Piyush Dak, Wei Zhao, Huai-Yuan Tseng, Deepanshu Dutta, Mohan Dunga
  • Publication number: 20190180831
    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: Application
    Filed: April 30, 2018
    Publication date: June 13, 2019
    Inventors: Pitamber Shukla, Mohan Dunga, Anubhav Khandelwal
  • Patent number: 10319680
    Abstract: A structure includes a metal interconnect structure embedded in a lower interconnect level dielectric layer overlying a substrate, at least one material layer overlying the metal interconnect structure, a first contact level dielectric layer overlying the at least one material layer; a metal contact via structure vertically extending through the first contact level dielectric layer and the at least one material layer and contacting a top surface of the metal interconnect structure, and an encapsulated tubular cavity laterally surrounding at least a lower portion of the metal contact via structure, and vertically extending through the at least one material layer.
    Type: Grant
    Filed: March 1, 2018
    Date of Patent: June 11, 2019
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Jongsun Sel, Masaaki Higashitani, Mohan Dunga, Fumiaki Toyama, Peter Rabkin
  • Patent number: 10304551
    Abstract: Apparatuses, systems, methods, and computer program products are disclosed for erase depth control. One apparatus includes a block of non-volatile storage cells. A controller is configured to perform a first erase operation on a block of non-volatile storage cells. A controller for a block is configured to determine a first set of storage cells of the block having a faster erase speed than a second set of storage cells of the block based on a verify voltage threshold. A controller for a block is configured to perform a second erase operation on the block using different voltages for a first set of storage cells and a second set of storage cells of the block.
    Type: Grant
    Filed: June 27, 2016
    Date of Patent: May 28, 2019
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Biswajit Ray, Mohan Dunga, Gerrit Jan Hemink, Changyuan Chen
  • Publication number: 20180342304
    Abstract: Systems and methods for string-based erase verify to create partial good blocks are disclosed. A block in non-volatile flash memory may include multiple strings. In practice, one string may be slower to erase than other strings. In analyzing the strings, the memory device may iteratively analyze the strings to verify as erased. As one example, the iterations are modified by changing which strings are erased in the subsequent iterations (e.g., only the strings that fail the erase verify). As another example, a predetermined number of iterations are performed after a majority of the strings are verified as erased. In this way, the strings verified as erased need not undergo more deep erasing, which may damage the strings. Further, if fewer than all of the strings are verified as erased, the memory device may designate the block as a partially good block.
    Type: Application
    Filed: May 26, 2017
    Publication date: November 29, 2018
    Applicant: Western Digital Technologies, Inc.
    Inventors: Mohan Dunga, Anubhav Khandelwal, Changyuan Chen, Biswajit Ray
  • Patent number: 10115459
    Abstract: An opening is formed through at least one dielectric material layer. A first metallic liner is formed on a bottom surface and sidewalls of the opening by depositing a first metallic material. A metal portion including an elemental metal or an intermetallic alloy of at least two elemental metals is formed on the first metallic liner. A second metallic liner including a second metallic material is formed directly on a top surface of the metal portion. The first metallic material and the second metallic material differ in composition. The first metallic liner and the second metallic liner contact an entirety of all surfaces of the metal portion. The first and second metallic liners can protect the metal portion from a subsequently deposited dielectric material layer, which may be formed as an air-gap dielectric layer after recessing the at least one dielectric material layer.
    Type: Grant
    Filed: September 29, 2017
    Date of Patent: October 30, 2018
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Katsuo Yamada, Tomoyasu Kakegawa, Peter Rabkin, Jayavel Pachamuthu, Mohan Dunga, Masaaki Higashitani
  • Patent number: 10074440
    Abstract: An erase operation includes one or more erase depth checks to detect the occurrence of shallow erased memory cells at the end of an erase process. Memory cells are subjected to erase and erase verification until erase verification success is achieved. At the end of successful erase verification, a subset of memory cells is read to detect an erase depth or level of the memory cells. If the erase depth check indicates that the subset memory cells are in a shallow erased condition, additional erasing and verification is performed.
    Type: Grant
    Filed: October 28, 2016
    Date of Patent: September 11, 2018
    Assignee: SanDisk Technologies LLC
    Inventors: Biswajit Ray, Mohan Dunga, Changyuan Chen
  • Patent number: 10008273
    Abstract: Apparatuses, systems, methods, and computer program products are disclosed for read level determination. A block of non-volatile storage cells has a plurality of bit lines. A controller for a block is configured to perform a first read on a set of storage cells using a first read level for the bit lines. A controller is configured to determine a second read level for at least a portion of the bit lines based at least partially on a first read. A controller is configured to perform a second read on a set of storage cells using a second read level for at least a portion of bit lines.
    Type: Grant
    Filed: June 13, 2016
    Date of Patent: June 26, 2018
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Biswajit Ray, Gerrit Jan Hemink, Mohan Dunga, Bijesh Rajamohanan, Changyuan Chen
  • Patent number: 9972396
    Abstract: In solid-state memory, such as flash memory, a section of memory is typically erased prior to each time data is programmed therein. In contrast, systems and methods for programming a solid-state memory device with writes from different data sets without an intervening erase are disclosed. For example, the memory device may first erase a block and thereafter program the block with a first data set, with some cells in an erased state and other cells in a non-erased state. After programming the first data set into the block and without erasing the block, the memory device programs the block with a second data set that is at least partially different from the first data set. In this regard, some of the cells, which were in a non-erased state after programming with the first data set, are in an erased state after programming with the second data set.
    Type: Grant
    Filed: June 1, 2017
    Date of Patent: May 15, 2018
    Assignee: Western Digital Technologies, Inc.
    Inventors: Himanshu Naik, Mohan Dunga, Changyuan Chen, Biswajit Ray
  • Publication number: 20180122489
    Abstract: An erase operation includes one or more erase depth checks to detect the occurrence of shallow erased memory cells at the end of an erase process. Memory cells are subjected to erase and erase verification until erase verification success is achieved. At the end of successful erase verification, a subset of memory cells is read to detect an erase depth or level of the memory cells. If the erase depth check indicates that the subset memory cells are in a shallow erased condition, additional erasing and verification is performed.
    Type: Application
    Filed: October 28, 2016
    Publication date: May 3, 2018
    Applicant: SanDisk Technologies LLC
    Inventors: Biswajit Ray, Mohan Dunga, Changyuan Chen