Patents by Inventor Dana Lee

Dana Lee 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).

  • Patent number: 8546214
    Abstract: Non-voltage storage and techniques for fabricating non-volatile storage are disclosed. In some embodiments, at least a portion of the control gates of non-volatile storage elements are formed from p-type polysilicon. In one embodiment, a lower portion of the control gate is p-type polysilicon. The upper portion of the control gate could be p-type polysilicon, n-type polysilicon, metal, metal nitride, etc. P-type polysilicon in the control gate may not deplete even at high Vpgm. Therefore, a number of problems that could occur if the control gate depleted are mitigated. For example, a memory cell having a control gate that is at least partially p-type polysilicon might be programmed with a lower Vpgm than a memory cell formed from n-type polysilicon.
    Type: Grant
    Filed: September 21, 2010
    Date of Patent: October 1, 2013
    Assignee: SanDisk Technologies Inc.
    Inventors: Takashi Whitney Orimoto, Atsushi Suyama, Ming Tian, Henry Chin, Henry Chien, Vinod Robert Purayath, Dana Lee
  • Patent number: 8542849
    Abstract: A device for audio mixing includes a cascade input port and a first cascade input component that includes a first cascade input level detector component that detects an audio level of an upstream sum audio signal. The first cascade input port also includes an attenuator component that attenuates the first upstream mix audio signal by a gain corresponding to difference between the upstream sum audio signal value and a detected audio level of an input sum audio signal. The device also includes a summer component where the signals summed include at least the first upstream sum audio signal. The device also includes an input sum level detector component that detects the audio level of the input sum audio signal. The device also includes a mixer component that is configured to provide a mix output signal by summing, where the signals summed include at least the first attenuated upstream mix signal.
    Type: Grant
    Filed: August 2, 2010
    Date of Patent: September 24, 2013
    Assignee: Rane Corporation
    Inventors: Douglas Christopher Bruey, Dana Lee Troxel
  • Patent number: 8526233
    Abstract: In a non-volatile storage system, one or more substrate channel regions for an unselected NAND string are boosted during programming to inhibit program disturb. A voltage applied to one or more unselected word lines associated with at least a first channel region is increased during a program pulse time period in which a program pulse is applied to a selected word line. The increase can be gradual, in the form of a ramp, or step-wise. The boosting level of the first channel region can be maintained. The increase in the voltage applied to the one or more unselected word lines can vary with temperature as well. Before the program pulse time period, the voltage applied to the one or more unselected word lines can be ramped up at a faster rate for a second, adjacent channel region than for the first channel region, to help isolate the channel regions.
    Type: Grant
    Filed: May 23, 2011
    Date of Patent: September 3, 2013
    Assignee: SanDisk Technologies Inc.
    Inventors: Gerrit Jan Hemink, Shih-Chung Lee, Anubhav Khandelwal, Henry Chin, Guirong Liang, Dana Lee
  • Publication number: 20130219107
    Abstract: A memory system or flash card may include a multi-level cell block with multiple states. Before the upper page is written, an intermediate state may be shifted to prevent or minimize overlapping of the states from the corresponding lower page. A write abort during the writing of the upper page will not result in a loss of data from the corresponding lower page.
    Type: Application
    Filed: February 21, 2012
    Publication date: August 22, 2013
    Applicant: SANDISK TECHNOLOGIES INC.
    Inventors: Dana Lee, Pao-Ling Koh, Jianmin Huang, Gautam A. Dusija
  • Patent number: 8472266
    Abstract: Methods and devices for sensing non-volatile storage devices in a way that reduces read disturb are disclosed. Techniques are used to reduce read disturb on memory cells that are neighbors to selected memory cells. For example, on a NAND string, the memory cells that are next to the selected memory cell presently being read may benefit. In one embodiment, when reading memory cells on a selected word line WLn, Vread+Delta is applied to WLn+2 and WLn?2. Applying Vread+Delta to the second neighbor word line may reduce read disturb to memory cells on the neighbor word line WLn+1.
    Type: Grant
    Filed: March 31, 2011
    Date of Patent: June 25, 2013
    Assignee: SanDisk Technologies Inc.
    Inventors: Anubhav Khandelwal, Jun Wan, Shih-Chung Lee, Dana Lee
  • Patent number: 8462547
    Abstract: A plurality of non-volatile storage elements on a common active layer are offset from neighbor non-volatile storage elements. This offsetting of non-volatile storage elements helps reduce interference from neighbor non-volatile storage elements. A method of manufacture is also described for fabricating the offset non-volatile storage elements.
    Type: Grant
    Filed: June 24, 2010
    Date of Patent: June 11, 2013
    Assignee: SanDisk Technologies Inc.
    Inventors: Jeffrey W. Lutze, Dana Lee
  • Publication number: 20130128666
    Abstract: The decision on whether to refresh or retire a memory block is based on the set of dynamic read values being used. In a memory system using a table of dynamic read values, the table is configured to include how to handle read error (retire, refresh) in addition to the read parameters for the different dynamic read cases. In a refinement, the read case number can used to prioritize blocks selected for refresh or retire. In cases where the read scrub is to be made more precise, multiple dynamic read cases can be applied. Further, which cases are applied can be intelligently selected.
    Type: Application
    Filed: March 30, 2012
    Publication date: May 23, 2013
    Inventors: Chris Avila, Jianmin Huang, Dana Lee
  • Patent number: 8432732
    Abstract: Techniques and corresponding circuitry are presented for the detection of wordline leakage in a memory array. In an exemplary embodiment, a capacitive voltage divider is used to translate the high voltage drop to low voltage drop that can be compared with a reference voltage to determine the voltage drop due to leakage. An on-chip self calibration method can help assure the accuracy of this technique for detecting leakage limit.
    Type: Grant
    Filed: July 9, 2010
    Date of Patent: April 30, 2013
    Assignee: SanDisk Technologies Inc.
    Inventors: Yan Li, Dana Lee, Jonathan Huynh
  • Patent number: 8406053
    Abstract: Dynamically determining read levels on chip (e.g., memory die) is disclosed herein. One method comprises reading a group of non-volatile storage elements on a memory die at a first set of read levels. Results of the two most recent of the read levels are stored on the memory die. A count of how many of the non-volatile storage elements in the group showed a different result between the reads for the two most recent read levels is determined. The determining is performed on the memory die using the results stored on the memory die. A dynamic read level is determined for distinguishing between a first pair of adjacent data states of the plurality of data states based on the read level when the count reaches a pre-determined criterion. Note that the read level may be dynamically determined on the memory die.
    Type: Grant
    Filed: September 21, 2011
    Date of Patent: March 26, 2013
    Assignee: SanDisk Technologies Inc.
    Inventors: Deepanshu Dutta, Dana Lee, Jeffrey Lutze
  • Patent number: 8406052
    Abstract: Non-volatile memory is programmed using source side hot electron injection. To generate a high voltage bit line for programming, the bit line corresponding to a selected memory cell is charged to a first level using a first low voltage. A second low voltage is applied to unselected bit lines adjacent to the selected bit line after charging. Because of capacitive coupling between the adjacent bit lines and the selected bit line, the selected bit line is boosted above the first voltage level by application of the second low voltage to the unselected bit lines. The column control circuitry for such a memory array does not directly apply the high voltage and thus, can be designed to withstand lower operating voltages, permitting low operating voltage circuitry to be used.
    Type: Grant
    Filed: February 16, 2011
    Date of Patent: March 26, 2013
    Assignee: SanDisk Technologies Inc.
    Inventors: Dana Lee, Hock So
  • Publication number: 20130070524
    Abstract: Dynamically determining read levels on chip (e.g., memory die) is disclosed herein. One method comprises reading a group of non-volatile storage elements on a memory die at a first set of read levels. Results of the two most recent of the read levels are stored on the memory die. A count of how many of the non-volatile storage elements in the group showed a different result between the reads for the two most recent read levels is determined. The determining is performed on the memory die using the results stored on the memory die. A dynamic read level is determined for distinguishing between a first pair of adjacent data states of the plurality of data states based on the read level when the count reaches a pre-determined criterion. Note that the read level may be dynamically determined on the memory die.
    Type: Application
    Filed: September 21, 2011
    Publication date: March 21, 2013
    Inventors: Deepanshu Dutta, Dana Lee, Jeffrey Lutze
  • Publication number: 20130051148
    Abstract: Read compensation for partially programmed blocks of non-volatile storage is provided. In partially programmed blocks, the threshold voltage distributions may be shifted down relative to their final positions. Upon receiving a request to read a page that is stored in a block, a determination may be made whether the block is partially programmed. If so, then a suitable compensation may be made when reading the requested page. This compensation may compensate for the non-volatile storage elements (or pages) in the block that have not yet been programmed. The amount of compensation may be based on the amount of interference that would be caused to the requested page by later programming of the other pages. The compensation may compensate for shifts in threshold voltage distributions of the requested page that would occur from later programming of other pages.
    Type: Application
    Filed: August 22, 2011
    Publication date: February 28, 2013
    Inventors: Dana Lee, Ken Oowada
  • Publication number: 20130028021
    Abstract: Techniques for a post-write read are presented. In an exemplary embodiment, a combined simultaneous sensing of multiple word lines is used in order to identify a problem in one or more of these word lines. That is, sensing voltages are concurrently applied to the control gates of more than one memory cell whose resultant conductance is measured on the same bit line. The combined sensing result is use for measuring certain statistics of the cell voltage distribution (CVD) of multiple word lines and comparing it to the expected value. In case the measured statistics are different than expected, this may indicate that one or more of the sensed word lines may exhibit a failure and more thorough examination of the group of word lines can be performed.
    Type: Application
    Filed: December 21, 2011
    Publication date: January 31, 2013
    Inventors: Eran Sharon, Yan Li, Dana Lee, Idan Alrod
  • Publication number: 20120300550
    Abstract: In a non-volatile storage system, one or more substrate channel regions for an unselected NAND string are boosted during programming to inhibit program disturb. A voltage applied to one or more unselected word lines associated with at least a first channel region is increased during a program pulse time period in which a program pulse is applied to a selected word line. The increase can be gradual, in the form of a ramp, or step-wise. The boosting level of the first channel region can be maintained. The increase in the voltage applied to the one or more unselected word lines can vary with temperature as well. Before the program pulse time period, the voltage applied to the one or more unselected word lines can be ramped up at a faster rate for a second, adjacent channel region than for the first channel region, to help isolate the channel regions.
    Type: Application
    Filed: May 23, 2011
    Publication date: November 29, 2012
    Inventors: Gerrit Jan Hemink, Shih-Chung Lee, Anubhav Khandelwal, Henry Chin, Guirong Liang, Dana Lee
  • Patent number: 8321727
    Abstract: Systems and methods are disclosed that are responsive to a rate of change of a performance parameter of a memory. In a particular embodiment, a rate of change of a performance parameter of a non-volatile memory is determined. The rate of change is compared to a threshold, and an action is performed in response to determining that the rate of change satisfies the threshold.
    Type: Grant
    Filed: June 29, 2009
    Date of Patent: November 27, 2012
    Assignee: Sandisk Technologies Inc.
    Inventors: Manuel Antonio D'Abreu, Stephen Skala, Dana Lee
  • Publication number: 20120250414
    Abstract: Methods and devices for sensing non-volatile storage devices in a way that reduces read disturb are disclosed. Techniques are used to reduce read disturb on memory cells that are neighbors to selected memory cells. For example, on a NAND string, the memory cells that are next to the selected memory cell presently being read may benefit. In one embodiment, when reading memory cells on a selected word line WLn, Vread+Delta is applied to WLn+2 and WLn?2. Applying Vread+Delta to the second neighbor word line may reduce read disturb to memory cells on the neighbor word line WLn+1.
    Type: Application
    Filed: March 31, 2011
    Publication date: October 4, 2012
    Inventors: Anubhav Khandelwal, Jun Wan, Shih-Chung Lee, Dana Lee
  • Patent number: 8264890
    Abstract: Techniques are disclosed herein for erasing non-volatile memory cells. A subset of the memory cells are pre-conditioned prior to erase. The pre-conditioning alters the threshold voltage of the memory cells in a way that may help make later calculations more accurate. As an example, memory cells along a single word line might be pre-conditioned. After the pre-conditioning, the memory cells are erased using a trial erase pulse. A suitable magnitude for a second pulse is determined based on the magnitude of the trial erase pulse and data collected about the threshold voltage distribution after the trial erase. The second erase pulse is used to erase the memory cells. Determining an appropriate magnitude for the second erase pulse minimizes or eliminates over-erasing.
    Type: Grant
    Filed: July 13, 2010
    Date of Patent: September 11, 2012
    Assignee: SanDisk Technologies Inc.
    Inventors: Nima Mokhlesi, Dana Lee, Anubhav Khandelwal
  • Patent number: 8184479
    Abstract: A system for programming non-volatile storage is proposed that reduces the impact of interference from the boosting of neighbors. Memory cells are divided into two or more groups. In one example, the memory cells are divided into odd and even memory cells; however, other groupings can also be used. Prior to a first trigger, a first group of memory cells are programmed together with a second group of memory cells. Subsequent to the first trigger and prior to a second trigger, the first group of memory cells are programmed separately from the second group of memory cells. Subsequent to the second trigger, the first group of memory cells are programmed together with the second group of memory cells. Before and after both triggers, the first group of memory cells are verified together with the second group of memory cells.
    Type: Grant
    Filed: August 30, 2011
    Date of Patent: May 22, 2012
    Assignee: SanDisk Technologies Inc.
    Inventors: Dana Lee, Emilio Yero
  • Patent number: 8164135
    Abstract: Nonvolatile flash memory systems and methods are disclosed having a semiconductor substrate of a first conductivity type, including non-diffused channel regions through which electron flow is induced by application of voltage to associated gate elements. A plurality of floating gates are spaced apart from one another and each insulated from the channel region. A plurality of control gates are spaced apart from one another and insulated from the channel region, with each control gate being located between a first floating gate and a second floating gate and capacitively coupled thereto to form a subcell. A plurality of spaced-apart assist gates are insulated from the channel region, with each assist gate being located between and insulated from adjacent subcells. The channel is formed of three regions, two beneath adjacent control gate elements as well as a third region between the first two and beneath an associated assist gate.
    Type: Grant
    Filed: May 4, 2010
    Date of Patent: April 24, 2012
    Assignee: Silicon Storage Technology, Inc.
    Inventors: Changyuan Chen, Ya-Fen Lin, Dana Lee
  • Patent number: RE43870
    Abstract: A system for programming non-volatile storage is proposed that reduces the impact of interference from the boosting of neighbors. Memory cells are divided into two or more groups. In one example, the memory cells are divided into odd and even memory cells; however, other groupings can also be used. Prior to a first trigger, a first group of memory cells are programmed together with a second group of memory cells. Subsequent to the first trigger and prior to a second trigger, the first group of memory cells are programmed separately from the second group of memory cells. Subsequent to the second trigger, the first group of memory cells are programmed together with the second group of memory cells. Before and after both triggers, the first group of memory cells are verified together with the second group of memory cells.
    Type: Grant
    Filed: November 4, 2011
    Date of Patent: December 25, 2012
    Assignee: SanDisk Technologies Inc.
    Inventors: Dana Lee, Emilio Yero