Patents by Inventor Vinod Robert Purayath

Vinod Robert 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: 20110260235
    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: Application
    Filed: September 21, 2010
    Publication date: October 27, 2011
    Inventors: Takashi Whitney Orimoto, Atsushi Suyama, Ming Tian, Henry Chin, Henry Chien, Vinod Robert Purayath, Dana Lee
  • Publication number: 20110183475
    Abstract: A method of making a device includes providing a first device level containing first semiconductor rails separated by first insulating features, forming a sacrificial layer over the first device level, patterning the sacrificial layer and the first semiconductor rails in the first device level to form a plurality of second rails extending in a second direction, wherein the plurality of second rails extend at least partially into the first device level and are separated from each other by rail shaped openings which extend at least partially into the first device level, forming second insulating features between the plurality of second rails, removing the sacrificial layer, and forming second semiconductor rails between the second insulating features in a second device level over the first device level. The first semiconductor rails extend in a first direction. The second semiconductor rails extend in the second direction different from the first direction.
    Type: Application
    Filed: January 25, 2010
    Publication date: July 28, 2011
    Inventors: Vinod Robert PURAYATH, George MATAMIS, James KAI, Takashi ORIMOTO
  • Patent number: 7939407
    Abstract: Semiconductor-based non-volatile memory that includes memory cells with composite charge storage elements is fabricated using an etch stop layer during formation of at least a portion of the storage element. One composite charge storage element suitable for memory applications includes a first charge storage region having a larger gate length or dimension in a column direction than a second charge storage region. While not required, the different regions can be formed of the same or similar materials, such as polysilicon. Etching a second charge storage layer selectively with respect to a first charge storage layer can be performed using an interleaving etch-stop layer. The first charge storage layer is protected from overetching or damage during etching of the second charge storage layer. Consistency in the dimensions of the individual memory cells can be increased.
    Type: Grant
    Filed: November 9, 2009
    Date of Patent: May 10, 2011
    Assignee: SanDisk Corporation
    Inventors: Vinod Robert Purayath, George Matamis, Takashi Orimoto, James Kai
  • Patent number: 7888210
    Abstract: Fabricating semiconductor-based non-volatile memory that includes composite storage elements, such as those with first and second charge storage regions, can include etching more than one charge storage layer. To avoid inadvertent shorts between adjacent storage elements, a first charge storage layer for a plurality of non-volatile storage elements is formed into rows prior to depositing the second charge storage layer. Sacrificial features can be formed between the rows of the first charge storage layer that are adjacent in a column direction, before or after forming the rows of the first charge layer. After forming interleaving rows of the sacrificial features and the first charge storage layer, the second charge storage layer can be formed. The layers can then be etched into columns and the substrate etched to form isolation trenches between adjacent columns. The second charge storage layer can then be etched to form the second charge storage regions for the storage elements.
    Type: Grant
    Filed: December 19, 2007
    Date of Patent: February 15, 2011
    Assignee: SanDisk Corporation
    Inventors: Vinod Robert Purayath, George Matamis, Takashi Orimoto, James Kai
  • Publication number: 20110020992
    Abstract: Nanostructure-based charge storage regions are included in non-volatile memory devices and integrated with the fabrication of select gates and peripheral circuitry. One or more nanostructure coatings are applied over a substrate at a memory array area and a peripheral circuitry area. Various processes for removing the nanostructure coating from undesired areas of the substrate, such as target areas for select gates and peripheral transistors, are provided. One or more nanostructure coatings are formed using self-assembly based processes to selectively form nanostructures over active areas of the substrate in one example. Self-assembly permits the formation of discrete lines of nanostructures that are electrically isolated from one another without requiring patterning or etching of the nanostructure coating.
    Type: Application
    Filed: July 20, 2010
    Publication date: January 27, 2011
    Inventors: Vinod Robert Purayath, James K. Kai, Masaaki Higashitani, Takashi Orimoto, George Matamis, Henry Chien
  • Patent number: 7807529
    Abstract: Lithographically-defined spacing is used to define feature sizes during fabrication of semiconductor-based memory devices. Sacrificial features are formed over a substrate at a specified pitch having a line size and a space size defined by a photolithography pattern. Charge storage regions for storage elements are formed in the spaces between adjacent sacrificial features using the lithographically-defined spacing to fix a gate length or dimension of the charge storage regions in a column direction. Unequal line and space sizes at the specified pitch can be used to form feature sizes at less than the minimally resolvable feature size associated with the photolithography process. Larger line sizes can improve line-edge roughness while decreasing the dimension of the charge storage regions in the column direction.
    Type: Grant
    Filed: December 19, 2007
    Date of Patent: October 5, 2010
    Assignee: SanDisk Corporation
    Inventors: Vinod Robert Purayath, George Matamis, Takashi Orimoto, James Kai
  • Publication number: 20100190319
    Abstract: Techniques are provided for fabricating memory with metal nanodots as charge-storing elements. In an example approach, a coupling layer such as an amino functional silane group is provided on a gate oxide layer on a substrate. The substrate is dip coated in a colloidal solution having metal nanodots, causing the nanodots to attach to sites in the coupling layer. The coupling layer is then dissolved such as by rinsing or nitrogen blow drying, leaving the nanodots on the gate oxide layer. The nanodots react with the coupling layer and become negatively charged and arranged in a uniform monolayer, repelling a deposition of an additional monolayer of nanodots. In a configuration using a control gate over a high-k dielectric floating gate which includes the nanodots, the control gates may be separated by etching while the floating gate dielectric extends uninterrupted since the nanodots are electrically isolated from one another.
    Type: Application
    Filed: April 5, 2010
    Publication date: July 29, 2010
    Inventors: Vinod Robert Purayath, George Matamis, Takashi Orimoto, James Kai, Tuan D. Pham
  • Patent number: 7723186
    Abstract: Techniques are provided for fabricating memory with metal nanodots as charge-storing elements. In an example approach, a coupling layer such as an amino functional silane group is provided on a gate oxide layer on a substrate. The substrate is dip coated in a colloidal solution having metal nanodots, causing the nanodots to attach to sites in the coupling layer. The coupling layer is then dissolved such as by rinsing or nitrogen blow drying, leaving the nanodots on the gate oxide layer. The nanodots react with the coupling layer and become negatively charged and arranged in a uniform monolayer, repelling a deposition of an additional monolayer of nanodots. In a configuration using a control gate over a high-k dielectric floating gate which includes the nanodots, the control gates may be separated by etching while the floating gate dielectric extends uninterrupted since the nanodots are electrically isolated from one another.
    Type: Grant
    Filed: December 18, 2007
    Date of Patent: May 25, 2010
    Assignee: Sandisk Corporation
    Inventors: Vinod Robert Purayath, George Matamis, Takashi Orimoto, James Kai, Tuan D. Pham
  • Publication number: 20100081267
    Abstract: A method for fabricating a non-volatile storage element. The method comprises forming a layer of polysilicon floating gate material over a substrate and forming a layer of nitride at the surface of the polysilicon floating gate material. Floating gates are formed from the polysilicon floating gate material. Individual dielectric caps are formed from the nitride such that each individual nitride dielectric cap is self-aligned with one of the plurality of floating gates. An inter-gate dielectric layer is formed over the surface of the dielectric caps and the sides of the floating gates. Control gates are then formed with the inter-gate dielectric layer separating the control gates from the floating gates. The layer of nitride may be formed using SPA (slot plane antenna) nitridation. The layer of nitride may be formed prior to or after etching of the polysilicon floating gate material to form floating gates.
    Type: Application
    Filed: September 30, 2008
    Publication date: April 1, 2010
    Inventors: Vinod Robert Purayath, George Matamis, Takashi Orimoto, Henry Chien, James K. Kai
  • Publication number: 20100055889
    Abstract: Semiconductor-based non-volatile memory that includes memory cells with composite charge storage elements is fabricated using an etch stop layer during formation of at least a portion of the storage element. One composite charge storage element suitable for memory applications includes a first charge storage region having a larger gate length or dimension in a column direction than a second charge storage region. While not required, the different regions can be formed of the same or similar materials, such as polysilicon. Etching a second charge storage layer selectively with respect to a first charge storage layer can be performed using an interleaving etch-stop layer. The first charge storage layer is protected from overetching or damage during etching of the second charge storage layer. Consistency in the dimensions of the individual memory cells can be increased.
    Type: Application
    Filed: November 9, 2009
    Publication date: March 4, 2010
    Applicant: SANDISK CORPORATION
    Inventors: Vinod Robert Purayath, George Matamis, Takashi Orimoto, James Kai
  • Patent number: 7615447
    Abstract: Semiconductor-based non-volatile memory that includes memory cells with composite charge storage elements is fabricated using an etch stop layer during formation of at least a portion of the storage element. One composite charge storage element suitable for memory applications includes a first charge storage region having a larger gate length or dimension in a column direction than a second charge storage region. While not required, the different regions can be formed of the same or similar materials, such as polysilicon. Etching a second charge storage layer selectively with respect to a first charge storage layer can be performed using an interleaving etch-stop layer. The first charge storage layer is protected from overetching or damage during etching of the second charge storage layer. Consistency in the dimensions of the individual memory cells can be increased.
    Type: Grant
    Filed: December 19, 2007
    Date of Patent: November 10, 2009
    Assignee: SanDisk Corporation
    Inventors: Vinod Robert Purayath, George Matamis, Takashi Orimoto, James Kai
  • Publication number: 20090162951
    Abstract: A method of fabricating non-volatile memory is provided for memory cells employing a charge storage element with multiple charge storage regions. A first charge storage layer is formed over a tunnel dielectric layer at both a memory array region and an endpoint region of a semiconductor substrate. The first charge storage layer is removed from the endpoint region to expose the tunnel dielectric region. A second charge storage layer is formed over the first charge storage layer at the memory array region and over the tunnel dielectric layer at the endpoint region. When etching the second charge storage layer to form the stem regions of the memory cells, the tunnel dielectric layer provides a detectable endpoint signal to indicate that etching for the second charge storage layer is complete.
    Type: Application
    Filed: December 19, 2007
    Publication date: June 25, 2009
    Inventors: Takashi Orimoto, George Matamis, James Kai, Vinod Robert Purayath
  • Publication number: 20090163008
    Abstract: Lithographically-defined spacing is used to define feature sizes during fabrication of semiconductor-based memory devices. Sacrificial features are formed over a substrate at a specified pitch having a line size and a space size defined by a photolithography pattern. Charge storage regions for storage elements are formed in the spaces between adjacent sacrificial features using the lithographically-defined spacing to fix a gate length or dimension of the charge storage regions in a column direction. Unequal line and space sizes at the specified pitch can be used to form feature sizes at less than the minimally resolvable feature size associated with the photolithography process. Larger line sizes can improve line-edge roughness while decreasing the dimension of the charge storage regions in the column direction.
    Type: Application
    Filed: December 19, 2007
    Publication date: June 25, 2009
    Inventors: Vinod Robert Purayath, George Matamis, Takashi Orimoto, James Kai
  • Publication number: 20090162977
    Abstract: Fabricating semiconductor-based non-volatile memory that includes composite storage elements, such as those with first and second charge storage regions, can include etching more than one charge storage layer. To avoid inadvertent shorts between adjacent storage elements, a first charge storage layer for a plurality of non-volatile storage elements is formed into rows prior to depositing the second charge storage layer. Sacrificial features can be formed between the rows of the first charge storage layer that are adjacent in a column direction, before or after forming the rows of the first charge layer. After forming interleaving rows of the sacrificial features and the first charge storage layer, the second charge storage layer can be formed. The layers can then be etched into columns and the substrate etched to form isolation trenches between adjacent columns. The second charge storage layer can then be etched to form the second charge storage regions for the storage elements.
    Type: Application
    Filed: December 19, 2007
    Publication date: June 25, 2009
    Inventors: Vinod Robert Purayath, George Matamis, Takashi Orimoto, James Kai
  • Publication number: 20090163009
    Abstract: Semiconductor-based non-volatile memory that includes memory cells with composite charge storage elements is fabricated using an etch stop layer during formation of at least a portion of the storage element. One composite charge storage element suitable for memory applications includes a first charge storage region having a larger gate length or dimension in a column direction than a second charge storage region. While not required, the different regions can be formed of the same or similar materials, such as polysilicon. Etching a second charge storage layer selectively with respect to a first charge storage layer can be performed using an interleaving etch-stop layer. The first charge storage layer is protected from overetching or damage during etching of the second charge storage layer. Consistency in the dimensions of the individual memory cells can be increased.
    Type: Application
    Filed: December 19, 2007
    Publication date: June 25, 2009
    Inventors: Vinod Robert Purayath, George Matamis, Takashi Orimoto, James Kai
  • Publication number: 20090155967
    Abstract: Techniques are provided for fabricating memory with metal nanodots as charge-storing elements. In an example approach, a coupling layer such as an amino functional silane group is provided on a gate oxide layer on a substrate. The substrate is dip coated in a colloidal solution having metal nanodots, causing the nanodots to attach to sites in the coupling layer. The coupling layer is then dissolved such as by rinsing or nitrogen blow drying, leaving the nanodots on the gate oxide layer. The nanodots react with the coupling layer and become negatively charged and arranged in a uniform monolayer, repelling a deposition of an additional monolayer of nanodots. In a configuration using a control gate over a high-k dielectric floating gate which includes the nanodots, the control gates may be separated by etching while the floating gate dielectric extends uninterrupted since the nanodots are electrically isolated from one another.
    Type: Application
    Filed: December 18, 2007
    Publication date: June 18, 2009
    Inventors: Vinod Robert Purayath, George Matamis, Takashi Orimoto, James Kai, Tuan D. Pham
  • Publication number: 20090147576
    Abstract: Floating gates of a floating gate memory array have an inverted-T shape in both the bit line direction and the word line direction. Floating gates are formed using an etch stop layer that separates two polysilicon layers that form floating gates. Word lines extend over floating gates in one example, and word lines extend between floating gates in another example.
    Type: Application
    Filed: December 6, 2007
    Publication date: June 11, 2009
    Inventors: George Matamis, Henry Chien, Vinod Robert Purayath, Takashi Whitney Orimoto, James Kai