Patents by Inventor Vinod R. Purayath

Vinod R. Purayath 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: 20110256707
    Abstract: Fabricating non-volatile storage includes creating gate stacks with hard masks on top of the gate stacks. The gate stacks include two polysilicon layers and a dielectric layer between the two polysilicon layers. A portion of the hard mask over each gate stack is removed, leaving two separate tapered sections of each of the hard masks positioned above an upper polysilicon layer of the gate stacks. After the removing the portion of the hard masks, fluorine is implanted into the upper polysilicon layer of the gate stacks. Metal is added on the top surface of the upper polysilicon layer of the floating gate stacks. A silicidation process for the metal and the upper polysilicon layer of the gate stacks is preformed and the remaining tapered sections of the hard mask are removed. Other control lines can then be added.
    Type: Application
    Filed: April 18, 2010
    Publication date: October 20, 2011
    Inventors: Jayavel Pachamuthu, Vinod R. Purayath
  • Patent number: 7919809
    Abstract: A memory system is disclosed that includes a set of non-volatile storage elements. A given memory cell has a dielectric cap above the floating gate. In one embodiment, the dielectric cap resides between the floating gate and a conformal IPD layer. The dielectric cap reduces the leakage current between the floating gate and a control gate. The dielectric cap achieves this reduction by reducing the strength of the electric field at the top of the floating gate, which is where the electric field would be strongest without the dielectric cap for a floating gate having a narrow stem.
    Type: Grant
    Filed: July 9, 2008
    Date of Patent: April 5, 2011
    Assignee: SanDisk Corporation
    Inventors: Dana Lee, Henry Chin, James K. Kai, Takashi Whitney Orimoto, Vinod R. Purayath, George Matamis
  • Patent number: 7915664
    Abstract: A non-volatile storage system in which a sidewall insulating layer of a floating gate is significantly thinner than a thickness of a bottom insulating layer, and in which raised source/drain regions are provided. During programming or erasing, tunneling occurs predominantly via the sidewall insulating layer and the raised source/drain regions instead of via the bottom insulating layer. The floating gate may have a uniform width or an inverted T shape. The raised source/drain regions may be epitaxially grown from the substrate, and may include a doped region above an undoped region so that the channel length is effectively extended from beneath the floating gate and up into the undoped regions, so that short channel effects are reduced. The ratio of the thicknesses of the sidewall insulating layer to the bottom insulating layer may be about 0.3 to 0.67.
    Type: Grant
    Filed: April 17, 2008
    Date of Patent: March 29, 2011
    Assignee: SanDisk Corporation
    Inventors: Henry Chien, Takashi Orimoto, George Matamis, James Kai, Vinod R. Purayath
  • Patent number: 7915124
    Abstract: A method of fabricating a memory system is disclosed that includes a set of non-volatile storage elements. The method includes forming a floating gate having a top and at least two sides. A dielectric cap is formed at the top of the floating gate. An inter-gate dielectric layer is formed around the at least two sides of the floating gate and over the top of the dielectric cap. A control gate is formed over the top of the floating gate, the inter-gate dielectric layer separates the control gate from the floating gate. In one aspect, forming the dielectric cap includes implanting oxygen in the top of the floating gate and heating the floating gate to form the dielectric cap from the implanted oxygen and silicon from which the floating gate was formed.
    Type: Grant
    Filed: July 9, 2008
    Date of Patent: March 29, 2011
    Assignee: Sandisk Corporation
    Inventors: James K. Kai, Dana Lee, Takashi Whitney Orimoto, Vinod R. Purayath, George Matamis, Henry Chin
  • Publication number: 20100124813
    Abstract: A self-aligned fabrication process for three-dimensional non-volatile memory is disclosed. A double etch process forms conductors at a given level in self-alignment with memory pillars both underlying and overlying the conductors. Forming the conductors in this manner can include etching a first conductor layer using a first repeating pattern in a given direction to form a first portion of the conductors. Etching with the first pattern also defines two opposing sidewalls of an underlying pillar structure, thereby self-aligning the conductors with the pillars. After etching, a second conductor layer is deposited followed by a semiconductor layer stack. Etching with a second pattern that repeats in the same direction as the first pattern is performed, thereby forming a second portion of the conductors that is self-aligned with overlying layer stack lines. These layer stack lines are then etched orthogonally to define a second set of pillars overlying the conductors.
    Type: Application
    Filed: May 19, 2009
    Publication date: May 20, 2010
    Inventors: George Matamis, Henry Chien, James K. Kai, Takashi Orimoto, Vinod R Purayath, Er-Xuan Ping, Roy E. Scheuerlein
  • Publication number: 20100009503
    Abstract: A method of fabricating a memory system is disclosed that includes a set of non-volatile storage elements. The method includes forming a floating gate having a top and at least two sides. A dielectric cap is formed at the top of the floating gate. An inter-gate dielectric layer is formed around the at least two sides of the floating gate and over the top of the dielectric cap. A control gate is formed over the top of the floating gate, the inter-gate dielectric layer separates the control gate from the floating gate. In one aspect, forming the dielectric cap includes implanting oxygen in the top of the floating gate and heating the floating gate to form the dielectric cap from the implanted oxygen and silicon from which the floating gate was formed.
    Type: Application
    Filed: July 9, 2008
    Publication date: January 14, 2010
    Inventors: James K. Kai, Dana Lee, Takashi Whitney Orimoto, Vinod R. Purayath, George Matamis, Henry Chin
  • Publication number: 20100006915
    Abstract: A memory system is disclosed that includes a set of non-volatile storage elements. A given memory cell has a dielectric cap above the floating gate. In one embodiment, the dielectric cap resides between the floating gate and a conformal IPD layer. The dielectric cap reduces the leakage current between the floating gate and a control gate. The dielectric cap achieves this reduction by reducing the strength of the electric field at the top of the floating gate, which is where the electric field would be strongest without the dielectric cap for a floating gate having a narrow stem.
    Type: Application
    Filed: July 9, 2008
    Publication date: January 14, 2010
    Inventors: Dana Lee, Henry Chin, James K. Kai, Takashi Whitney Orimoto, Vinod R. Purayath, George Matamis
  • Publication number: 20090261398
    Abstract: A non-volatile storage system in which a sidewall insulating layer of a floating gate is significantly thinner than a thickness of a bottom insulating layer, and in which raised source/drain regions are provided. During programming or erasing, tunneling occurs predominantly via the sidewall insulating layer and the raised source/drain regions instead of via the bottom insulating layer. The floating gate may have a uniform width or an inverted T shape. The raised source/drain regions may be epitaxially grown from the substrate, and may include a doped region above an undoped region so that the channel length is effectively extended from beneath the floating gate and up into the undoped regions, so that short channel effects are reduced. The ratio of the thicknesses of the sidewall insulating layer to the bottom insulating layer may be about 0.3 to 0.67.
    Type: Application
    Filed: April 17, 2008
    Publication date: October 22, 2009
    Inventors: Henry Chien, Takashi Orimoto, George Matamis, James Kai, Vinod R. Purayath