Patents by Inventor Dengtao Zhao

Dengtao Zhao 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: 20110235428
    Abstract: To program a set of non-volatile storage elements, a set of programming pulses are applied to the control gates (or other terminals) of the non-volatile storage elements. The programming pulses have pulse widths that vary as a function of simulated pulse magnitude data. The programming pulses can also have pulse magnitudes that vary based on measurements taken while testing the set of non-volatile storage elements. In one embodiment, the pulse widths are determined after simulation performed prior to fabrication of the non-volatile storage elements. In another embodiment, the pulse magnitudes are calculated after fabrication of the non-volatile storage elements.
    Type: Application
    Filed: June 2, 2011
    Publication date: September 29, 2011
    Inventors: Nima Mokhlesi, Dengtao Zhao, Henry Chin, Tapan Samaddar
  • Patent number: 7978520
    Abstract: To program a set of non-volatile storage elements, a set of programming pulses are applied to the control gates (or other terminals) of the non-volatile storage elements. The programming pulses have pulse widths that vary as a function of simulated pulse magnitude data. The programming pulses can also have pulse magnitudes that vary based on measurements taken while testing the set of non-volatile storage elements. In one embodiment, the pulse widths are determined after simulation performed prior to fabrication of the non-volatile storage elements. In another embodiment, the pulse magnitudes are calculated after fabrication of the non-volatile storage elements.
    Type: Grant
    Filed: September 27, 2007
    Date of Patent: July 12, 2011
    Assignee: SanDisk Corporation
    Inventors: Nima Mokhlesi, Dengtao Zhao, Henry Chin, Tapan Samaddar
  • Patent number: 7966550
    Abstract: Data stored in non-volatile storage is decoded using iterative probabilistic decoding. An error correcting code such as a low density parity check code may be used. In one approach, initial reliability metrics, such as logarithmic likelihood ratios, are used in decoding sensed states of a set of non-volatile storage element. The decoding attempts to converge by adjusting the reliability metrics for bits in code words which represent the sensed state. Soft data bits are read from the memory if the decoding fails to converge. Initial reliability metric values are provided after receiving the hard read results and at each phase of the soft bit operation(s). In one embodiment, a second soft bit is read from the memory using multiple subsets of soft bit compare levels. While reading at the second subset of compare levels, decoding can be performed based on the first subset data.
    Type: Grant
    Filed: March 31, 2007
    Date of Patent: June 21, 2011
    Assignee: SanDisk Technologies Inc.
    Inventors: Nima Mokhlesi, Henry Chin, Dengtao Zhao
  • Patent number: 7966546
    Abstract: Data stored in non-volatile storage is decoded using iterative probabilistic decoding. An error correcting code such as a low density parity check code may be used. In one approach, initial reliability metrics, such as logarithmic likelihood ratios, are used in decoding sensed states of a set of non-volatile storage element. The decoding attempts to converge by adjusting the reliability metrics for bits in code words which represent the sensed state. Soft data bits are read from the memory if the decoding fails to converge. Initial reliability metric values are provided after receiving the hard read results and at each phase of the soft bit operation(s). In one embodiment, a second soft bit is read from the memory using multiple subsets of soft bit compare levels. While reading at the second subset of compare levels, decoding can be performed based on the first subset data.
    Type: Grant
    Filed: March 31, 2007
    Date of Patent: June 21, 2011
    Assignee: SanDisk Technologies Inc.
    Inventors: Nima Mokhlesi, Henry Chin, Dengtao Zhao
  • Publication number: 20110131473
    Abstract: Data stored in non-volatile storage is decoded using iterative probabilistic decoding and multiple read operations to achieve greater reliability. An error correcting code such as a low density parity check code may be used. In one approach, initial reliability metrics, such as logarithmic likelihood ratios, are used in decoding read data of a set of non-volatile storage element. The decoding attempts to converge by adjusting the reliability metrics for bits in code words which represent the sensed state. If convergence does not occur, e.g., within a set time period, the state of the non-volatile storage element is sensed again, current values of the reliability metrics in the decoder are adjusted, and the decoding again attempts to converge.
    Type: Application
    Filed: February 10, 2011
    Publication date: June 2, 2011
    Applicant: SANDISK CORPORATION
    Inventors: Nima Mokhlesi, Henry Chin, Dengtao Zhao
  • Patent number: 7904793
    Abstract: Data stored in non-volatile storage is decoded using iterative probabilistic decoding and multiple read operations to achieve greater reliability. An error correcting code such as a low density parity check code may be used. In one approach, initial reliability metrics, such as logarithmic likelihood ratios, are used in decoding read data of a set of non-volatile storage element. The decoding attempts to converge by adjusting the reliability metrics for bits in code words which represent the sensed state. If convergence does not occur, e.g., within a set time period, the state of the non-volatile storage element is sensed again, current values of the reliability metrics in the decoder are adjusted, and the decoding again attempts to converge. In another approach, the initial reliability metrics are based on multiple reads. Tables which store the reliability metrics and adjustments based on the sensed states can be prepared before decoding occurs.
    Type: Grant
    Filed: March 29, 2007
    Date of Patent: March 8, 2011
    Assignee: SanDisk Corporation
    Inventors: Nima Mokhlesi, Henry Chin, Dengtao Zhao
  • Publication number: 20100258851
    Abstract: Nanocrystal memories and methods of making the same are disclosed. In one embodiment, a memory device comprises a substrate, a tunneling oxide, a silicide nanocrystal floating gate, and a control oxide. The tunneling oxide is positioned upon a first surface of the substrate, the silicide nanocrystal floating gate is positioned upon the tunneling oxide, and the control oxide positioned upon the nanocrystal floating gate.
    Type: Application
    Filed: April 9, 2010
    Publication date: October 14, 2010
    Applicant: The Regents of the University of California
    Inventors: Jianlin Liu, Dengtao Zhao, Yan Zhu, Ruigang Li, Bei Li
  • Patent number: 7797480
    Abstract: Data stored in non-volatile storage is read using sense operations and associated pre-conditioning waveforms. The pre-conditioning waveform provides a short term history for a non-volatile element which is analogous to the conditions experienced during programming when a programming pulse is applied prior to a verify operation. The pre-conditioning waveform can cause electrons to enter and exit trap sites, for instance, so that the accuracy of a probabilistic decoding process is improved. In one approach, multiple read operations are performed, some with pre-conditioning waveforms and some without. Pre-conditioning waveforms with different characteristics, such as amplitude, shape, duration and time before the associated read pulse, can also be used. For probabilistic decoding, initial reliability metrics can be developed based on multiple reads. Tables which store the reliability metrics can then be prepared for use in subsequent decoding.
    Type: Grant
    Filed: March 29, 2007
    Date of Patent: September 14, 2010
    Assignee: Sandisk Corporation
    Inventors: Nima Mokhlesi, Dengtao Zhao, Henry Chin
  • Patent number: 7551477
    Abstract: An array of non-volatile storage elements includes a first group of non-volatile storage elements connected to a selected word line, a second group of non-volatile storage elements connected to the selected word line, a first group of bit lines in communication with the first group of non-volatile storage elements, a second group of bit lines in communication with the second group of non-volatile storage elements, a first set of sense modules located at a first location and connected to the first group of bit lines, and a second set of sense modules located at a second location and connected to the second group of bit lines. The first set of sense modules applies a first bit line voltage based on the bit line distance between the first set of sense modules and the first group of non-volatile storage elements. The second set of sense modules applies a second bit line voltage based on the bit line distance between the second set of sense modules and the second group of non-volatile storage elements.
    Type: Grant
    Filed: September 26, 2007
    Date of Patent: June 23, 2009
    Assignee: SanDisk Corporation
    Inventors: Nima Mokhlesi, Dengtao Zhao, Man Mui, Hao Nguyen, Seungpil Lee, Deepak Chandra Sekar, Tapan Samaddar
  • Patent number: 7535764
    Abstract: In some non-volatile storage systems, a block of data memory cells is manufactured with a dummy word line at the bottom of the block, at the top of the block, and/or at other locations. By selectively programming memory cells on the dummy word line(s), the resistances associated with the data memory cells can be changed to account for different programmed data patterns.
    Type: Grant
    Filed: March 21, 2007
    Date of Patent: May 19, 2009
    Assignee: SanDisk Corporation
    Inventors: Henry Chin, Nima Mokhlesi, Dengtao Zhao
  • Publication number: 20090086544
    Abstract: To program a set of non-volatile storage elements, a set of programming pulses are applied to the control gates (or other terminals) of the non-volatile storage elements. The programming pulses have pulse widths that vary as a function of simulated pulse magnitude data. The programming pulses can also have pulse magnitudes that vary based on measurements taken while testing the set of non-volatile storage elements. In one embodiment, the pulse widths are determined after simulation performed prior to fabrication of the non-volatile storage elements. In another embodiment, the pulse magnitudes are calculated after fabrication of the non-volatile storage elements.
    Type: Application
    Filed: September 27, 2007
    Publication date: April 2, 2009
    Inventors: Nima Mokhlesi, Dengtao Zhao, Henry Chin, Tapan Samaddar
  • Publication number: 20090080265
    Abstract: An array of non-volatile storage elements includes a first group of non-volatile storage elements connected to a selected word line, a second group of non-volatile storage elements connected to the selected word line, a first group of bit lines in communication with the first group of non-volatile storage elements, a second group of bit lines in communication with the second group of non-volatile storage elements, a first set of sense modules located at a first location and connected to the first group of bit lines, and a second set of sense modules located at a second location and connected to the second group of bit lines. The first set of sense modules applies a first bit line voltage based on the bit line distance between the first set of sense modules and the first group of non-volatile storage elements. The second set of sense modules applies a second bit line voltage based on the bit line distance between the second set of sense modules and the second group of non-volatile storage elements.
    Type: Application
    Filed: September 26, 2007
    Publication date: March 26, 2009
    Inventors: Nima Mokhlesi, Dengtao Zhao, Man Mui, Hao Nguyen, Seungpil Lee, Deepak Chandra Sekar, Tapan Samaddar
  • Patent number: 7463528
    Abstract: Reading and verify operations are performed on non-volatile storage elements using temperature-compensated read voltages for unselected word lines, and/or for select gates such as drain or source side select gates of a NAND string. In one approach, while a read or verify voltage is applied to a selected word line, temperature-compensated read voltages are applied to unselected word lines and select gates. Word lines which directly neighbor the selected word line can receive a voltage which is not temperature compensated, or which is temperature-compensated to a reduced degree. The read or verify voltage applied to the selected word line can also be temperature-compensated. The temperature compensation may also account for word line position.
    Type: Grant
    Filed: December 18, 2007
    Date of Patent: December 9, 2008
    Assignee: SanDisk Corporation
    Inventors: Nima Mokhlesi, Dengtao Zhao
  • Patent number: 7460407
    Abstract: Reading and verify operations are performed on non-volatile storage elements using temperature-compensated read voltages for unselected word lines, and/or for select gates such as drain or source side select gates of a NAND string. In one approach, while a read or verify voltage is applied to a selected word line, temperature-compensated read voltages are applied to unselected word lines and select gates. Word lines which directly neighbor the selected word line can receive a voltage which is not temperature compensated, or which is temperature-compensated to a reduced degree. The read or verify voltage applied to the selected word line can also be temperature-compensated. The temperature compensation may also account for word line position.
    Type: Grant
    Filed: December 18, 2007
    Date of Patent: December 2, 2008
    Assignee: SanDisk Corporation
    Inventors: Nima Mokhlesi, Dengtao Zhao
  • Publication number: 20080273388
    Abstract: In some non-volatile storage systems, a block of data memory cells is manufactured with a dummy word line at the bottom of the block, at the top of the block, and/or at other locations. By selectively programming memory cells on the dummy word line(s), the resistances associated with the data memory cells can be changed to account for different programmed data patterns.
    Type: Application
    Filed: March 21, 2007
    Publication date: November 6, 2008
    Inventors: Henry Chin, Nima Mokhlesi, Dengtao Zhao
  • Publication number: 20080250300
    Abstract: Data stored in non-volatile storage is decoded using iterative probabilistic decoding and multiple read operations to achieve greater reliability. An error correcting code such as a low density parity check code may be used. In one approach, initial reliability metrics, such as logarithmic likelihood ratios, are used in decoding read data of a set of non-volatile storage element. The decoding attempts to converge by adjusting the reliability metrics for bits in code words which represent the sensed state. If convergence does not occur, e.g., within a set time period, the state of the non-volatile storage element is sensed again, current values of the reliability metrics in the decoder are adjusted, and the decoding again attempts to converge. In another approach, the initial reliability metrics are based on multiple reads. Tables which store the reliability metrics and adjustments based on the sensed states can be prepared before decoding occurs.
    Type: Application
    Filed: March 29, 2007
    Publication date: October 9, 2008
    Inventors: Nima Mokhlesi, Henry Chin, Dengtao Zhao
  • Publication number: 20080244162
    Abstract: Data stored in non-volatile storage is read using sense operations and associated pre-conditioning waveforms. The pre-conditioning waveform provides a short term history for a non-volatile element which is analogous to the conditions experienced during programming when a programming pulse is applied prior to a verify operation. The pre-conditioning waveform can cause electrons to enter and exit trap sites, for instance, so that the accuracy of a probabilistic decoding process is improved. In one approach, multiple read operations are performed, some with pre-conditioning waveforms and some without. Pre-conditioning waveforms with different characteristics, such as amplitude, shape, duration and time before the associated read pulse, can also be used. For probabilistic decoding, initial reliability metrics can be developed based on multiple reads. Tables which store the reliability metrics can then be prepared for use in subsequent decoding.
    Type: Application
    Filed: March 29, 2007
    Publication date: October 2, 2008
    Inventors: Nima Mokhlesi, Dengtao Zhao, Henry Chin
  • Publication number: 20080244360
    Abstract: Data stored in non-volatile storage is decoded using iterative probabilistic decoding. An error correcting code such as a low density parity check code may be used. In one approach, initial reliability metrics, such as logarithmic likelihood ratios, are used in decoding sensed states of a set of non-volatile storage element. The decoding attempts to converge by adjusting the reliability metrics for bits in code words which represent the sensed state. Soft data bits are read from the memory if the decoding fails to converge. Initial reliability metric values are provided after receiving the hard read results and at each phase of the soft bit operation(s). In one embodiment, a second soft bit is read from the memory using multiple subsets of soft bit compare levels. While reading at the second subset of compare levels, decoding can be performed based on the first subset data.
    Type: Application
    Filed: March 31, 2007
    Publication date: October 2, 2008
    Inventors: Nima Mokhlesi, Henry Chin, Dengtao Zhao
  • Publication number: 20080244338
    Abstract: Data stored in non-volatile storage is decoded using iterative probabilistic decoding. An error correcting code such as a low density parity check code may be used. In one approach, initial reliability metrics, such as logarithmic likelihood ratios, are used in decoding sensed states of a set of non-volatile storage element. The decoding attempts to converge by adjusting the reliability metrics for bits in code words which represent the sensed state. Soft data bits are read from the memory if the decoding fails to converge. Initial reliability metric values are provided after receiving the hard read results and at each phase of the soft bit operation(s). In one embodiment, a second soft bit is read from the memory using multiple subsets of soft bit compare levels. While reading at the second subset of compare levels, decoding can be performed based on the first subset data.
    Type: Application
    Filed: March 31, 2007
    Publication date: October 2, 2008
    Inventors: Nima Mokhlesi, Henry Chin, Dengtao Zhao
  • Patent number: 7391650
    Abstract: Reading and verify operations are performed on non-volatile storage elements using temperature-compensated read voltages for unselected word lines, and/or for select gates such as drain or source side select gates of a NAND string. In one approach, while a read or verify voltage is applied to a selected word line, temperature-compensated read voltages are applied to unselected word lines and select gates. Word lines which directly neighbor the selected word line can receive a voltage which is not temperature compensated, or which is temperature-compensated to a reduced degree. The read or verify voltage applied to the selected word line can also be temperature-compensated. The temperature compensation may also account for word line position.
    Type: Grant
    Filed: June 16, 2006
    Date of Patent: June 24, 2008
    Assignee: Sandisk Corporation
    Inventors: Nima Mokhlesi, Dengtao Zhao