Patents by Inventor Kiran Ponnuru

Kiran Ponnuru 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: 7512014
    Abstract: Systems and methods in accordance with various embodiments can provide for comprehensive erase verification and defect detection in non-volatile semiconductor memory. In one embodiment, the results of erasing a group of storage elements is verified using a plurality of test conditions to better detect defective and/or insufficiently erased storage elements of the group. For example, the results of erasing a NAND string can be verified by testing charging of the string in a plurality of directions with the storage elements biased to turn on if in an erased state. If a string of storage elements passes a first test process or operation but fails a second test process or operation, the string can be determined to have failed the erase process and possibly be defective. By testing charging or conduction of the string in a plurality of directions, defects in any transistors of the string that are masked under one set of conditions may be exposed under a second set of bias conditions.
    Type: Grant
    Filed: December 21, 2005
    Date of Patent: March 31, 2009
    Assignee: SanDisk Corporation
    Inventors: Dat Tran, Kiran Ponnuru, Jian Chen, Jeffrey W. Lutze, Jun Wan
  • Patent number: 7508720
    Abstract: Systems and methods in accordance with various embodiments can provide for comprehensive erase verification and defect detection in non-volatile semiconductor memory. In one embodiment, the results of erasing a group of storage elements is verified using a plurality of test conditions to better detect defective and/or insufficiently erased storage elements of the group. For example, the results of erasing a NAND string can be verified by testing charging of the string in a plurality of directions with the storage elements biased to turn on if in an erased state. If a string of storage elements passes a first test process or operation but fails a second test process or operation, the string can be determined to have failed the erase process and possibly be defective. By testing charging or conduction of the string in a plurality of directions, defects in any transistors of the string that are masked under one set of conditions may be exposed under a second set of bias conditions.
    Type: Grant
    Filed: December 21, 2005
    Date of Patent: March 24, 2009
    Assignee: SanDisk Corporation
    Inventors: Dat Tran, Kiran Ponnuru, Jian Chen, Jeffrey W. Lutze, Jun Wan
  • Patent number: 7463532
    Abstract: Systems and methods in accordance with various embodiments can provide for comprehensive erase verification and defect detection in non-volatile semiconductor memory. In one embodiment, the results of erasing a group of storage elements is verified using a plurality of test conditions to better detect defective and/or insufficiently erased storage elements of the group. For example, the results of erasing a NAND string can be verified by testing charging of the string in a plurality of directions with the storage elements biased to turn on if in an erased state. If a string of storage elements passes a first test process or operation but fails a second test process or operation, the string can be determined to have failed the erase process and possibly be defective. By testing charging or conduction of the string in a plurality of directions, defects in any transistors of the string that are masked under one set of conditions may be exposed under a second set of bias conditions.
    Type: Grant
    Filed: December 21, 2005
    Date of Patent: December 9, 2008
    Assignee: SanDisk Corporation
    Inventors: Dat Tran, Kiran Ponnuru, Jian Chen, Jeffrey W. Lutze, Jun Wan
  • Patent number: 7450435
    Abstract: Systems and methods in accordance with various embodiments can provide for comprehensive erase verification and defect detection in non-volatile semiconductor memory. In one embodiment, the results of erasing a group of storage elements is verified using a plurality of test conditions to better detect defective and/or insufficiently erased storage elements of the group. For example, the results of erasing a NAND string can be verified by testing charging of the string in a plurality of directions with the storage elements biased to turn on if in an erased state. If a string of storage elements passes a first test process or operation but fails a second test process or operation, the string can be determined to have failed the erase process and possibly be defective. By testing charging or conduction of the string in a plurality of directions, defects in any transistors of the string that are masked under one set of conditions may be exposed under a second set of bias conditions.
    Type: Grant
    Filed: December 21, 2005
    Date of Patent: November 11, 2008
    Assignee: SanDisk Corporation
    Inventors: Dat Tran, Kiran Ponnuru, Jian Chen, Jeffrey W. Lutze, Jun Wan
  • Publication number: 20070141731
    Abstract: Future operability predictor testing is incorporated into the fabrication of integrated circuits that utilize redundancy. Select reliability testing can be used to identify circuit elements such as memory cells that fail or become defective over time. Future operability tests and associated stress conditions are then developed for application during the fabrication process to identify memory cells that may pose a future operability concern before they actually fail. Memory cells that are determined to pose a future operability concern are replaced by redundant memory cells.
    Type: Application
    Filed: December 20, 2005
    Publication date: June 21, 2007
    Inventors: Gerrit Hemink, Loc Tu, Jian Chen, Kiran Ponnuru
  • Publication number: 20060133156
    Abstract: Systems and methods in accordance with various embodiments can provide for comprehensive erase verification and defect detection in non-volatile semiconductor memory. In one embodiment, the results of erasing a group of storage elements is verified using a plurality of test conditions to better detect defective and/or insufficiently erased storage elements of the group. For example, the results of erasing a NAND string can be verified by testing charging of the string in a plurality of directions with the storage elements biased to turn on if in an erased state. If a string of storage elements passes a first test process or operation but fails a second test process or operation, the string can be determined to have failed the erase process and possibly be defective. By testing charging or conduction of the string in a plurality of directions, defects in any transistors of the string that are masked under one set of conditions may be exposed under a second set of bias conditions.
    Type: Application
    Filed: December 21, 2005
    Publication date: June 22, 2006
    Inventors: Dat Tran, Kiran Ponnuru, Jian Chen, Jeffrey Lutze, Jun Wan
  • Publication number: 20060098494
    Abstract: Systems and methods in accordance with various embodiments can provide for comprehensive erase verification and defect detection in non-volatile semiconductor memory. In one embodiment, the results of erasing a group of storage elements is verified using a plurality of test conditions to better detect defective and/or insufficiently erased storage elements of the group. For example, the results of erasing a NAND string can be verified by testing charging of the string in a plurality of directions with the storage elements biased to turn on if in an erased state. If a string of storage elements passes a first test process or operation but fails a second test process or operation, the string can be determined to have failed the erase process and possibly be defective. By testing charging or conduction of the string in a plurality of directions, defects in any transistors of the string that are masked under one set of conditions may be exposed under a second set of bias conditions.
    Type: Application
    Filed: December 21, 2005
    Publication date: May 11, 2006
    Inventors: Dat Tran, Kiran Ponnuru, Jian Chen, Jeffrey Lutze, Jun Wan
  • Publication number: 20060098495
    Abstract: Systems and methods in accordance with various embodiments can provide for comprehensive erase verification and defect detection in non-volatile semiconductor memory. In one embodiment, the results of erasing a group of storage elements is verified using a plurality of test conditions to better detect defective and/or insufficiently erased storage elements of the group. For example, the results of erasing a NAND string can be verified by testing charging of the string in a plurality of directions with the storage elements biased to turn on if in an erased state. If a string of storage elements passes a first test process or operation but fails a second test process or operation, the string can be determined to have failed the erase process and possibly be defective. By testing charging or conduction of the string in a plurality of directions, defects in any transistors of the string that are masked under one set of conditions may be exposed under a second set of bias conditions.
    Type: Application
    Filed: December 21, 2005
    Publication date: May 11, 2006
    Inventors: Dat Tran, Kiran Ponnuru, Jian Chen, Jeffrey Lutze, Jun Wan
  • Publication number: 20060098493
    Abstract: Systems and methods in accordance with various embodiments can provide for comprehensive erase verification and defect detection in non-volatile semiconductor memory. In one embodiment, the results of erasing a group of storage elements is verified using a plurality of test conditions to better detect defective and/or insufficiently erased storage elements of the group. For example, the results of erasing a NAND string can be verified by testing charging of the string in a plurality of directions with the storage elements biased to turn on if in an erased state. If a string of storage elements passes a first test process or operation but fails a second test process or operation, the string can be determined to have failed the erase process and possibly be defective. By testing charging or conduction of the string in a plurality of directions, defects in any transistors of the string that are masked under one set of conditions may be exposed under a second set of bias conditions.
    Type: Application
    Filed: December 21, 2005
    Publication date: May 11, 2006
    Inventors: Dat Tran, Kiran Ponnuru, Jian Chen, Jeffrey Lutze, Jun Wan
  • Patent number: 7009889
    Abstract: Systems and methods in accordance with various embodiments can provide for comprehensive erase verification and defect detection in non-volatile semiconductor memory. In one embodiment, the results of erasing a group of storage elements is verified using a plurality of test conditions to better detect defective and/or insufficiently erased storage elements of the group. For example, the results of erasing a NAND string can be verified by testing charging of the string in a plurality of directions with the storage elements biased to turn on if in an erased state. If a string of storage elements passes a first test process or operation but fails a second test process or operation, the string can be determined to have failed the erase process and possibly be defective. By testing charging or conduction of the string in a plurality of directions, defects in any transistors of the string that are masked under one set of conditions may be exposed under a second set of bias conditions.
    Type: Grant
    Filed: May 28, 2004
    Date of Patent: March 7, 2006
    Assignee: Sandisk Corporation
    Inventors: Dat Tran, Kiran Ponnuru, Jian Chen, Jeffrey W. Lutze, Jun Wan
  • Publication number: 20050265081
    Abstract: Systems and methods in accordance with various embodiments can provide for comprehensive erase verification and defect detection in non-volatile semiconductor memory. In one embodiment, the results of erasing a group of storage elements is verified using a plurality of test conditions to better detect defective and/or insufficiently erased storage elements of the group. For example, the results of erasing a NAND string can be verified by testing charging of the string in a plurality of directions with the storage elements biased to turn on if in an erased state. If a string of storage elements passes a first test process or operation but fails a second test process or operation, the string can be determined to have failed the erase process and possibly be defective. By testing charging or conduction of the string in a plurality of directions, defects in any transistors of the string that are masked under one set of conditions may be exposed under a second set of bias conditions.
    Type: Application
    Filed: May 28, 2004
    Publication date: December 1, 2005
    Inventors: Dat Tran, Kiran Ponnuru, Jian Chen, Jeffrey Lutze, Jun Wan