Patents by Inventor Sucheta Nallamothu

Sucheta Nallamothu 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: 20050122780
    Abstract: An exemplary NAND string memory array provides for capacitive boosting of a half-selected memory cell channel to reduce program disturb effects of the half selected cell. To reduce the effect of leakage current degradation of the boosted level, multiple programming pulses of a shorter duration are employed to limit the time period during which such leakage currents may degrade the voltage within the unselected NAND strings. In addition, multiple series select devices at one or both ends of each NAND string further ensure reduced leakage through such select devices, for both unselected and selected NAND strings. In certain exemplary embodiments, a memory array includes series-connected NAND strings of memory cell transistors having a charge storage dielectric, and includes more than one plane of memory cells formed above a substrate.
    Type: Application
    Filed: December 5, 2003
    Publication date: June 9, 2005
    Inventors: En-Hsing Chen, Andrew Walker, Roy Scheuerlein, Sucheta Nallamothu, Alper Ilkbahar, Luca Fasoli
  • Publication number: 20040145024
    Abstract: An exemplary NAND string memory array provides for capacitive boosting of a half-selected memory cell channel to reduce program disturb effects of the half selected cell. To reduce the effect of leakage current degradation of the boosted level, multiple programming pulses of a shorter duration are employed to limit the time period during which such leakage currents may degrade the voltage within the unselected NAND strings. In addition, multiple series select devices at one or both ends of each NAND string further ensure reduced leakage through such select devices, for both unselected and selected NAND strings. In certain exemplary embodiments, a memory array includes series-connected NAND strings of memory cell transistors having a charge storage dielectric, and includes more than one plane of memory cells formed above a substrate.
    Type: Application
    Filed: December 5, 2003
    Publication date: July 29, 2004
    Inventors: En-Hsing Chen, Andrew J. Walker, Roy E. Scheuerlein, Sucheta Nallamothu, Alper Ilkbahar, Luca G. Fasoli
  • Publication number: 20040124466
    Abstract: A three-dimensional flash memory array incorporates thin film transistors having a charge storage dielectric arranged in series-connected NAND strings to achieve a 4F2 memory cell layout. The memory array may be programmed and erased using only tunneling currents, and no leakage paths are formed through non-selected memory cells. Each NAND string includes two block select devices for respectively coupling one end of the NAND string to a global bit line, and the other end to a shared bias node. Pairs of NAND strings within a block share the same global bit line. The memory cells are preferably depletion mode SONOS devices, as are the block select devices. The memory cells may be programmed to a near depletion threshold voltage, and the block select devices are maintained in a programmed state having a near depletion mode threshold voltage. NAND strings on more than one layer may be connected to global bit lines on a single layer.
    Type: Application
    Filed: December 31, 2002
    Publication date: July 1, 2004
    Inventors: Andrew J. Walker, En-Hsing Chen, Sucheta Nallamothu, Roy E. Scheuerlein, Alper Ilkbahar, Luca Fasoli, Igor Kouznetsov, Christopher Petti
  • Publication number: 20040124415
    Abstract: A thin film transistor with a channel less than 100 angstroms thick, preferably less than 80 angstroms thick, preferably less than 60 angstroms thick. The very thin channel reduces variability of threshold voltage from one TFT to the next. This is particularly advantageous for TFT memory arrays. It is possible that an extremely thin channel restricts the size of grains, forcing many small grains to be formed.
    Type: Application
    Filed: December 31, 2002
    Publication date: July 1, 2004
    Inventors: Andrew J. Walker, S. Brad Herner, Maitreyee Mahajani, En-Hsing Chen, Roy E. Scheuerlein, Sucheta Nallamothu, Mark Clark
  • Publication number: 20040125629
    Abstract: A three-dimensional flash memory array incorporates thin film transistors having a charge storage dielectric arranged in series-connected NAND strings to achieve a 4F2 memory cell layout. The memory array may be programmed and erased using only tunneling currents, and no leakage paths are formed through non-selected memory cells. Each NAND string includes two block select devices for respectively coupling one end of the NAND string to a global bit line, and the other end to a shared bias node. Pairs of NAND strings within a block share the same global bit line. The memory cells are preferably depletion mode SONOS devices, as are the block select devices. The memory cells may be programmed to a near depletion threshold voltage, and the block select devices are maintained in a programmed state having a near depletion mode threshold voltage. NAND strings on more than one layer may be connected to global bit lines on a single layer.
    Type: Application
    Filed: December 31, 2002
    Publication date: July 1, 2004
    Inventors: Roy E. Scheuerlein, Christopher Petti, Andrew J. Walker, En-Hsing Chen, Sucheta Nallamothu, Alper Ilkbahar, Luca Fasoli, Igor Kouznetsov