Patents by Inventor Maitreyee Mahajani

Maitreyee Mahajani 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: 20070217263
    Abstract: An exemplary NAND string memory array includes at least one plane of memory cells, said memory cells comprising thin film modifiable conductance switch devices and which cells are arranged in a plurality of series-connected NAND strings, said NAND strings including a series select device at each end thereof. Another exemplary NAND string memory array includes a group of more than four adjacent NAND strings within the same memory block each associated with a respective global bit line not shared by the other NAND string of the group. Another exemplary NAND string memory array includes NAND strings on identical pitch as their respective global bit lines.
    Type: Application
    Filed: May 21, 2007
    Publication date: September 20, 2007
    Inventors: Luca Fasoli, Roy Scheuerlein, En-Hsing Chen, Sucheta Nallamothu, Maitreyee Mahajani, Andrew Walker
  • Publication number: 20070126033
    Abstract: A dual-gate device is formed over and insulated from a semiconductor substrate which may include additional functional circuits that can be interconnected to the dual-gate device. The dual-gate device includes two semiconductor devices formed on opposite surfaces of a common active semiconductor region which is provided a thickness and material sufficient to isolate the semiconductor devices from electrostatically interacting. In one embodiment, one of the semiconductor devices includes a charge storing layer, such as an ONO layer. Such a dual-gate device is suitable for use in a non-volatile memory array.
    Type: Application
    Filed: February 6, 2007
    Publication date: June 7, 2007
    Inventors: Andrew Walker, Maitreyee Mahajani
  • Patent number: 7221588
    Abstract: An exemplary NAND string memory array includes at least one plane of memory cells, said memory cells comprising thin film modifiable conductance switch devices and which cells are arranged in a plurality of series-connected NAND strings, and NAND strings including a series select device at each end thereof. Another exemplary NAND string memory array includes a group of more than four adjacent NAND strings within the same memory block each associated with a respective global bit line not shared by the other NAND string of the group. Another exemplary NAND string memory array includes NAND strings on identical pitch as their respective global bit lines.
    Type: Grant
    Filed: December 5, 2003
    Date of Patent: May 22, 2007
    Assignee: Sandisk 3D LLC
    Inventors: Luca G. Fasoli, Roy E. Scheuerlein, En-Hsing Chen, Sucheta Nallamothu, Maitreyee Mahajani, Andrew J. Walker
  • Publication number: 20070084406
    Abstract: The present invention generally provides a batch processing chamber having a quartz chamber, at least one heater block, an inject assembly coupled to one side of the quartz chamber, and an exhaust assembly coupled to an opposite side of the quartz chamber. In one embodiment, the inject assembly is independently temperature controlled. In another embodiment, at least one temperature sensor is disposed outside the quartz chamber.
    Type: Application
    Filed: October 13, 2005
    Publication date: April 19, 2007
    Inventors: Joseph Yudovsky, Robert Cook, Yeong Kim, Alexander Tam, Maitreyee Mahajani, Adam Brailove, Steve Ghanayem
  • Publication number: 20070084408
    Abstract: An apparatus for batch processing of a wafer is disclosed. In one embodiment the batch processing apparatus includes a bell jar furnace having a diffuser disposed between gas inlets and the substrate positioned within the furnace to direct flows within the chamber around the perimeter of the substrate.
    Type: Application
    Filed: May 5, 2006
    Publication date: April 19, 2007
    Inventors: Joseph Yudovsky, Tai Ngo, Cesar Tejamo, Maitreyee Mahajani, Brendan McDougall, Yi-Chiau Huang, Robert Cook, Yeong Kim, Alexander Tam, Adam Brailove, Steve Ghanayem
  • Publication number: 20070049053
    Abstract: Embodiments of the invention provide methods for forming a material on a substrate which includes exposing a plurality of substrates within a batch process chamber to a first oxidizing gas during a pretreatment process, exposing the substrates sequentially to a precursor and a second oxidizing gas during an ALD cycle and repeating the ALD cycle to form a material on the substrates. In a preferred example, a hafnium precursor is used during the ALD process to form a hafnium-containing material, such as hafnium oxide. In one example, the first and second oxidizing gases are the same oxidizing gases. In a preferred example, the first and second oxidizing gases are different oxidizing gases, such that the pretreatment process contains ozone and the ALD process contains water vapor.
    Type: Application
    Filed: August 26, 2005
    Publication date: March 1, 2007
    Inventor: Maitreyee Mahajani
  • Publication number: 20060189077
    Abstract: An improved method for fabricating a three dimensional monolithic memory with increased density. The method includes forming conductors preferably comprising tungsten, then filling and planarizing; above the conductors forming semiconductor elements preferably comprising two diode portions and an antifuse, then filling and planarizing; and continuing to form conductors and semiconductor elements in multiple stories of memories. The arrangement of processing steps and the choice of materials decreases aspect ratio of each memory cell, improving the reliability of gap fill and preventing etch undercut.
    Type: Application
    Filed: April 10, 2006
    Publication date: August 24, 2006
    Applicant: SanDisk 3D LLC
    Inventors: S. Herner, Maitreyee Mahajani
  • Publication number: 20060115939
    Abstract: A dual-gate device is formed over and insulated from a semiconductor substrate which may include additional functional circuits that can be interconnected to the dual-gate device. The dual-gate device includes two semiconductor devices formed on opposite surfaces of a common active semiconductor region which is provided a thickness and material sufficient to isolate the semiconductor devices from electrostatically interacting. In one embodiment, one of the semiconductor devices includes a charge storing layer, such as an ONO layer. Such a dual-gate device is suitable for use in a non-volatile memory array.
    Type: Application
    Filed: November 29, 2004
    Publication date: June 1, 2006
    Inventors: Andrew Walker, Maitreyee Mahajani
  • Patent number: 7026212
    Abstract: An improved method for fabricating a three dimensional monolithic memory with increased density. The method includes forming conductors preferably comprising tungsten, then filling and planarizing; above the conductors forming semiconductor elements preferably comprising two diode portions and an antifuse, then filling and planarizing; and continuing to form conductors and semiconductor elements in multiple stories of memories. The arrangement of processing steps and the choice of materials decreases aspect ratio of each memory cell, improving the reliability of gap fill and preventing etch undercut.
    Type: Grant
    Filed: May 26, 2004
    Date of Patent: April 11, 2006
    Assignee: Matrix Semiconductors, Inc.
    Inventors: S. Brad Herner, Maitreyee Mahajani
  • Publication number: 20060071074
    Abstract: The invention provides for polysilicon vias connecting conductive polysilicon layers formed at different heights. Polysilicon vias are advantageously used in a monolithic three dimensional memory array of charge storage transistors. Polysilicon vias according to the present invention can be used, for example, to connect the channel layer of a first device level of charge storage transistor memory cells to the channel layer of a second device layer of such cells formed above the first device level. Similarly, vias according to the present invention can be used to connect the wordline of a first device level of charge storage transistor memory cells to the channel layer of a second device layer of such cells.
    Type: Application
    Filed: September 29, 2004
    Publication date: April 6, 2006
    Applicant: Matrix Semiconductor, Inc.
    Inventors: Michael Konevecki, Usha Raghuram, Maitreyee Mahajani, Sucheta Nallamothu, Andrew Walker, Tanmay Kumar
  • Patent number: 7012299
    Abstract: The traditional nitride-only charge storage layer of a SONOS device is replaced by a multifilm charge storage layer comprising more than one dielectric material. Examples of such a multifilm charge storage layer are alternating layers of silicon nitride and silicon dioxide, or alternating layers of silicon nitride and aluminum oxide. The use of more than one material introduces additional barriers to migration of charge carriers within the charge storage layer, and improves both endurance and retention of a SONOS-type memory cell comprising such a charge storage layer.
    Type: Grant
    Filed: September 23, 2003
    Date of Patent: March 14, 2006
    Assignee: Matrix Semiconductors, Inc.
    Inventors: Maitreyee Mahajani, Andrew J. Walker, En-Hsing Chen
  • Patent number: 7009275
    Abstract: An improved method for fabricating a three dimensional monolithic memory with increased density. The method includes forming conductors preferably comprising tungsten, then filling and planarizing; above the conductors forming semiconductor elements preferably comprising two diode portions and an antifuse, then filling and planarizing; and continuing to form conductors and semiconductor elements in multiple stories of memories. The arrangement of processing steps and the choice of materials decreases aspect ratio of each memory cell, improving the reliability of gap fill and preventing etch undercut.
    Type: Grant
    Filed: May 26, 2004
    Date of Patent: March 7, 2006
    Assignee: Matrix Semiconductor, Inc.
    Inventors: S. Brad Herner, Maitreyee Mahajani
  • Patent number: 6995422
    Abstract: An improved method for fabricating a three dimensional monolithic memory with increased density. The method includes forming conductors preferably comprising tungsten, then filling and planarizing; above the conductors forming semiconductor elements preferably comprising two diode portions and an antifuse, then filling and planarizing; and continuing to form conductors and semiconductor elements in multiple stories of memories. The arrangement of processing steps and the choice of materials decreases aspect ratio of each memory cell, improving the reliability of gap fill and preventing etch undercut.
    Type: Grant
    Filed: May 26, 2004
    Date of Patent: February 7, 2006
    Assignee: Matrix Semiconductor, Inc.
    Inventors: S. Brad Herner, Maitreyee Mahajani
  • Patent number: 6984561
    Abstract: An improved method for fabricating a three dimensional monolithic memory with increased density. The method includes forming conductors preferably comprising tungsten, then filling and planarizing; above the conductors forming semiconductor elements preferably comprising two diode portions and an antifuse, then filling and planarizing; and continuing to form conductors and semiconductor elements in multiple stories of memories. The arrangement of processing steps and the choice of materials decreases aspect ratio of each memory cell, improving the reliability of gap fill and preventing etch undercut.
    Type: Grant
    Filed: May 26, 2004
    Date of Patent: January 10, 2006
    Assignee: Matrix Semiconductor, Inc.
    Inventors: S. Brad Herner, Maitreyee Mahajani
  • Patent number: 6960794
    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: Grant
    Filed: December 31, 2002
    Date of Patent: November 1, 2005
    Assignee: Matrix Semiconductor, Inc.
    Inventors: Andrew J. Walker, S. Brad Herner, Maitreyee Mahajani, En-Hsing Chen, Roy E. Scheuerlein, Sucheta Nallamothu, Mark Clark
  • Patent number: 6952030
    Abstract: A three dimensional monolithic memory comprising a memory cell allowing for increased density is disclosed. In the memory cell of the present invention, a bottom conductor preferably comprising tungsten is formed. Above the bottom conductor a semiconductor element preferably comprises two diode portions and an antifuse. Above the semiconductor element are additional conductors and semiconductor elements in multiple stones of memories. The arrangement of processing steps and the choice of materials decreases aspect ratio of each memory cell, improving the reliability of gap fill and preventing etch undercut.
    Type: Grant
    Filed: May 26, 2004
    Date of Patent: October 4, 2005
    Assignee: Matrix Semiconductor, Inc.
    Inventors: S. Brad Herner, Maitreyee Mahajani
  • Publication number: 20050122779
    Abstract: An exemplary NAND string memory array includes at least one plane of memory cells, said memory cells comprising thin film modifiable conductance switch devices and which cells are arranged in a plurality of series-connected NAND strings, and NAND strings including a series select device at each end thereof. Another exemplary NAND string memory array includes a group of more than four adjacent NAND strings within the same memory block each associated with a respective global bit line not shared by the other NAND string of the group. Another exemplary NAND string memory array includes NAND strings on identical pitch as their respective global bit lines.
    Type: Application
    Filed: December 5, 2003
    Publication date: June 9, 2005
    Inventors: Luca Fasoli, Roy Scheuerlein, En-Hsing Chen, Sucheta Nallamothu, Maitreyee Mahajani, Andrew Walker
  • Publication number: 20050062098
    Abstract: The traditional nitride-only charge storage layer of a SONOS device is replaced by a multifilm charge storage layer comprising more than one dielectric material. Examples of such a multifilm charge storage layer are alternating layers of silicon nitride and silicon dioxide, or alternating layers of silicon nitride and aluminum oxide. The use of more than one material introduces additional barriers to migration of charge carriers within the charge storage layer, and improves both endurance and retention of a SONOS-type memory cell comprising such a charge storage layer.
    Type: Application
    Filed: September 23, 2003
    Publication date: March 24, 2005
    Inventors: Maitreyee Mahajani, Andrew Walker, En-Hsing Chen
  • Patent number: 6858899
    Abstract: A thin film transistor includes an insulating substrate, an active layer located over the substrate, a gate electrode located over the substrate; and a charge storage region located between the active layer and the gate electrode. The charge storage region includes a tunneling dielectric located adjacent to the active layer, a blocking dielectric located adjacent to the gate electrode and a charge storage dielectric located between the tunneling dielectric and the blocking dielectric. At least one of the tunneling dielectric, the charge storage dielectric and the blocking dielectric comprises a layer having a dielectric constant greater than 3.9, such as a metal oxide layer.
    Type: Grant
    Filed: October 15, 2002
    Date of Patent: February 22, 2005
    Assignee: Matrix Semiconductor, Inc.
    Inventors: Maitreyee Mahajani, Andrew J. Walker
  • Publication number: 20050012119
    Abstract: An improved method for fabricating a three dimensional monolithic memory with increased density. The method includes forming conductors preferably comprising tungsten, then filling and planarizing; above the conductors forming semiconductor elements preferably comprising two diode portions and an antifuse, then filling and planarizing; and continuing to form conductors and semiconductor elements in multiple stories of memories. The arrangement of processing steps and the choice of materials decreases aspect ratio of each memory cell, improving the reliability of gap fill and preventing etch undercut.
    Type: Application
    Filed: May 26, 2004
    Publication date: January 20, 2005
    Applicant: MATRIX SEMICONDUCTOR
    Inventors: S. Herner, Maitreyee Mahajani