Patents by Inventor Gautam A. Dusija

Gautam A. Dusija 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: 20150162087
    Abstract: In a charge trapping memory, data that would otherwise be likely to remain adjacent to unwritten word lines is written three times, along three immediately adjacent word lines. The middle copy is protected from charge migration on either side and is considered a safe copy for later reading. Dummy data may be programmed along a number of word lines to format a block for good data retention.
    Type: Application
    Filed: December 6, 2013
    Publication date: June 11, 2015
    Applicant: SanDisk Technologies Inc.
    Inventors: Deepak Raghu, Chris Avila, Gautam A. Dusija, Yingda Dong
  • Patent number: 9037902
    Abstract: Techniques, related to a flash memory device having a non-volatile memory array (NVM), for recovering from a write interrupt resulting from host-supplied memory voltage fault are disclosed. A memory controller is configured to control a response to an occurrence of the write-interrupt, the response including writing to the NVM, after the memory voltage is verified as being within an acceptable range, one or more of a safe copy of a portion of a first sector of upper-page data and a safe copy of a portion of a second sector of lower-page data, and terminating the write interrupt. Terminating the write-interrupt may include receiving new data from the host while avoiding sending an error message to the host.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: May 19, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Gautam Dusija, Jianmin Huang, Chris N. Avila, Grishma S. Shah, Yi-Chieh Chen, Alexander K. Mak, Farookh Moogat
  • Publication number: 20150117099
    Abstract: Layers in a multi-layer memory array are categorized according to likely error rates as predicted from their memory hole diameters. Data to be stored along a word line in a high risk layer is subject to a redundancy operation (e.g. XOR) with data to be stored along a word line in a low risk layer so that the risk of both being bad is low.
    Type: Application
    Filed: May 22, 2014
    Publication date: April 30, 2015
    Applicant: SanDisk Technologies Inc.
    Inventors: Deepak Raghu, Gautam A. Dusija, Chris Avila, Yingda Dong, Man Mui, Xiying Costa, Pao-Ling Koh
  • Publication number: 20150121157
    Abstract: Layers in a multi-layer memory array are categorized according to likely error rates as predicted from their memory hole diameters. Data to be stored along a word line in a high risk layer is subject to a redundancy operation (e.g. XOR) with data to be stored along a word line in a low risk layer so that the risk of both being bad is low.
    Type: Application
    Filed: October 28, 2013
    Publication date: April 30, 2015
    Applicant: SanDisk Technologies Inc.
    Inventors: Deepak Raghu, Gautam A. Dusija, Chris Avila, Yingda Dong, Man Mui, Xiying Costa, Pao-Ling Koh
  • Publication number: 20150121156
    Abstract: Memory hole diameter in a three dimensional memory array may be calculated from characteristics that are observed during programming. Suitable operating parameters may be selected for operating a block based on memory hole diameters. Hot counts of blocks may be adjusted according to memory hole size so that blocks that are expected to fail earlier because of small memory holes are more lightly used than blocks with larger memory holes.
    Type: Application
    Filed: October 28, 2013
    Publication date: April 30, 2015
    Applicant: SanDisk Technologies Inc.
    Inventors: Deepak Raghu, Gautam A. Dusija, Chris Avila, Yingda Dong, Man Mui, Alexander Kwok-Tung Mak, Pao-Ling Koh
  • Patent number: 9015407
    Abstract: In a three-dimensional NAND memory in which a block contains multiple separately-selectable sets of strings connected to the same set of bit lines, sets of strings are zoned, and different operating parameters applied to different zones. Operating parameters for a zone are obtained from characterizing a reference set of strings in the zone.
    Type: Grant
    Filed: May 28, 2014
    Date of Patent: April 21, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Gautam A. Dusija, Yingda Dong, Chris Avila, Deepak Raghu, Pao-Ling Koh
  • Patent number: 9009398
    Abstract: Data that is stored in a higher error rate format in a nonvolatile memory is backed up in a lower error rate format. Data to be stored may be transferred once to on-chip data latches where it is maintained while it is programmed in both the high error rate format and the low error rate format without being resent to the nonvolatile memory.
    Type: Grant
    Filed: May 19, 2014
    Date of Patent: April 14, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Chris Avila, Gautam Dusija, Jian Chen, Mrinal Kochar, Abhijeet Manohar
  • Publication number: 20150092493
    Abstract: A 3D NAND stacked non-volatile memory device, comprising: a string comprising a plurality of non-volatile storage elements, the string comprises a channel and extends vertically through layers of the 3D stacked non-volatile memory device, and the plurality of storage elements are subdivided into different groups based on group assignments, each group of the different groups comprises multiple adjacent storage elements of the plurality of storage elements; and a control circuit in communication with the string, the control circuit, to perform a Pseudo Block Operation Mode.
    Type: Application
    Filed: December 8, 2014
    Publication date: April 2, 2015
    Applicant: SanDisk Technologies Inc.
    Inventors: Xiying Costa, Alexander Kwok-Tung Mak, Chris Avila, Gautam Dusija, Man Mui
  • Publication number: 20150085574
    Abstract: In a three dimensional NAND memory, increased threshold voltages in back gate transistors may cause program failures, particularly along word lines near back gates. When back gate transistor threshold voltages cannot be returned to a desired threshold voltage range then modified program conditions, including increased back gate voltage, may be used to allow programming.
    Type: Application
    Filed: September 20, 2013
    Publication date: March 26, 2015
    Applicant: SanDisk Technology Inc.
    Inventors: Deepak Raghu, Gautam Dusija, Chris Avila, Yingda Dong, Man Mui
  • Publication number: 20150063028
    Abstract: When a bad block is found in a nonvolatile memory array, the block is marked as a bad block so that it is not subsequently used. The block is also reconfigured as a bad block by increasing resistance of vertical NAND strings in the block by increasing threshold voltage of at least some transistors along vertical NAND strings, for example, select transistors or memory cell transistors.
    Type: Application
    Filed: May 29, 2014
    Publication date: March 5, 2015
    Applicant: SanDisk Technologies Inc.
    Inventors: Deepak Raghu, Gautam Dusija, Chris Avila, Yingda Dong, Man Mui
  • Patent number: 8972675
    Abstract: Data that is stored in a higher error rate format in a 3-D nonvolatile memory is backed up in a lower error rate format. Later, the higher error rate copy is sampled to determine if it is acceptable. A sampling pattern samples all word lines of a string and at least one word line of each string of the block.
    Type: Grant
    Filed: May 16, 2014
    Date of Patent: March 3, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Chris Avila, Gautam A. Dusija, Jian Chen
  • Patent number: 8966330
    Abstract: When a bad block is found in a nonvolatile memory array, the block is marked as a bad block so that it is not subsequently used. The block is also reconfigured as a bad block by increasing resistance of vertical NAND strings in the block by increasing threshold voltage of at least some transistors along vertical NAND strings, for example, select transistors or memory cell transistors.
    Type: Grant
    Filed: May 29, 2014
    Date of Patent: February 24, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Deepak Raghu, Gautam Dusija, Chris Avila, Yingda Dong, Man Mui
  • Patent number: 8964467
    Abstract: Multiple bits of data are programmed together to each cell of a segment of a word line while other segments of the same word line are unprogrammed. Subsequently, additional segments are similarly programmed. Data is read from a partially programmed word line (with a mix of programmed and unprogrammed segments) using a single reading scheme.
    Type: Grant
    Filed: May 22, 2014
    Date of Patent: February 24, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Gautam A. Dusija, Chris Avila, Deepak Raghu, Yingda Dong, Man Mui, Alexander Kwok-Tung Mak, Pao-Ling Koh
  • Publication number: 20150012802
    Abstract: Data that is stored in a higher error rate format in a nonvolatile memory is backed up in a lower error rate format. Data to be stored may be transferred once to on-chip data latches where it is maintained while it is programmed in both the high error rate format and the low error rate format without being resent to the nonvolatile memory.
    Type: Application
    Filed: May 19, 2014
    Publication date: January 8, 2015
    Applicant: SanDisk Technologies Inc.
    Inventors: Chris Avila, Gautam Dusija, Jian Chen, Mrinal Kochar, Abhijeet Manohar
  • Patent number: 8929141
    Abstract: Erasing memory cells in certain 3-D NAND charge-storage memory arrays is achieved by rapidly charging vertical conductors using Gate Induced Drain Leakage (GIDL) current generated in select transistors. When bit line voltage drops below its nominal value, select line voltage is controlled to maintain a constant voltage difference between bit line voltage and select line voltage thus maintaining a gate-drain voltage difference in select transistors that provides sufficient GIDL current for erase.
    Type: Grant
    Filed: October 2, 2013
    Date of Patent: January 6, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Deepak Raghu, Gautam Dusija, Chris Avila, Yingda Dong, Man Mui, Pao-Ling Koh
  • Publication number: 20150006790
    Abstract: Data that is stored in a higher error rate format in a 3-D nonvolatile memory is backed up in a lower error rate format. Later, the higher error rate copy is sampled to determine if it is acceptable. A sampling pattern samples all word lines of a string and at least one word line of each string of the block.
    Type: Application
    Filed: May 16, 2014
    Publication date: January 1, 2015
    Applicant: SanDisk Technologies Inc.
    Inventors: Chris Avila, Gautam A. Dusija, Jian Chen
  • Patent number: 8923054
    Abstract: A 3D NAND stacked non-volatile memory device, comprising: a string comprising a plurality of non-volatile storage elements, the string comprises a channel and extends vertically through layers of the 3D stacked non-volatile memory device, and the plurality of storage elements are subdivided into different groups based on group assignments, each group of the different groups comprises multiple adjacent storage elements of the plurality of storage elements; and a control circuit in communication with the string, the control circuit, to perform a Pseudo Block Operation Mode.
    Type: Grant
    Filed: January 10, 2014
    Date of Patent: December 30, 2014
    Assignee: SanDisk Technologies Inc.
    Inventors: Xiying Costa, Alexander Kwog-Tung Mak, Chris Avila, Gautam Dusija, Man Mui
  • Publication number: 20140369122
    Abstract: A 3D NAND stacked non-volatile memory device, comprising: a string comprising a plurality of non-volatile storage elements, the string comprises a channel and extends vertically through layers of the 3D stacked non-volatile memory device, and the plurality of storage elements are subdivided into different groups based on group assignments, each group of the different groups comprises multiple adjacent storage elements of the plurality of storage elements; and a control circuit in communication with the string, the control circuit, to perform a Pseudo Block Operation Mode.
    Type: Application
    Filed: January 10, 2014
    Publication date: December 18, 2014
    Applicant: SanDisk Technologies Inc.
    Inventors: Xiying Costa, Alexander Kwok-Tung Mak, Chris Avila, Gautam Dusija, Man Mui
  • Publication number: 20140369123
    Abstract: A 3D NAND stacked non-volatile memory device, comprising: a string comprising a plurality of non-volatile storage elements, the string comprises a channel and extends vertically through layers of the 3D stacked non-volatile memory device, and the plurality of storage elements are subdivided into different groups based on group assignments, each group of the different groups comprises multiple adjacent storage elements of the plurality of storage elements; and a control circuit in communication with the string, the control circuit, to perform a Pseudo Block Operation Mode.
    Type: Application
    Filed: May 9, 2014
    Publication date: December 18, 2014
    Applicant: SanDisk Technologies Inc.
    Inventors: Xiying Costa, Alexander Kwok-Tung Mak, Chris Avila, Gautam Dusija, Man Mui
  • Patent number: 8913431
    Abstract: A 3D NAND stacked non-volatile memory device, comprising: a string comprising a plurality of non-volatile storage elements, the string comprises a channel and extends vertically through layers of the 3D stacked non-volatile memory device, and the plurality of storage elements are subdivided into different groups based on group assignments, each group of the different groups comprises multiple adjacent storage elements of the plurality of storage elements; and a control circuit in communication with the string, the control circuit, to perform a Pseudo Block Operation Mode.
    Type: Grant
    Filed: May 9, 2014
    Date of Patent: December 16, 2014
    Assignee: SanDisk Technologies Inc.
    Inventors: Xiying Costa, Alexander Kwok-Tung Mak, Chris Avila, Gautam Dusija, Man Mui