Patents by Inventor Takashi Orimoto

Takashi Orimoto 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: 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: 7619926
    Abstract: A string of nonvolatile memory cells connected in series includes fixed charges located between floating gates and the underlying substrate surface. Such a fixed charge affects distribution of charge carriers in an underlying portion of the substrate and thus affects threshold voltage of a device. A fixed charge layer may extend over source/drain regions also.
    Type: Grant
    Filed: March 29, 2007
    Date of Patent: November 17, 2009
    Assignee: SanDisk Corporation
    Inventors: Takashi Orimoto, George Matamis, Henry Chien, 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: 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
  • Patent number: 7592225
    Abstract: High density semiconductor devices and methods of fabricating the same are provided. Spacer fabrication techniques are utilized to form circuit elements having reduced feature sizes, which in some instances are smaller than the smallest lithographically resolvable element size of the process being used. Spacers are formed that serve as a mask for etching one or more layers beneath the spacers. An etch stop pad layer having a material composition substantially similar to the spacer material is provided between a dielectric layer and an insulating sacrificial layer such as silicon nitride. When etching the sacrificial layer, the matched pad layer provides an etch stop to avoid damaging and reducing the size of the dielectric layer. The matched material compositions further provide improved adhesion for the spacers, thereby improving the rigidity and integrity of the spacers.
    Type: Grant
    Filed: January 15, 2007
    Date of Patent: September 22, 2009
    Assignee: SanDisk Corporation
    Inventors: James Kai, George Matamis, Tuan Duc Pham, Masaaki Higashitani, Takashi Orimoto
  • Patent number: 7592223
    Abstract: Non-volatile semiconductor memory devices with dual control gate memory cells and methods of forming the same using integrated select and peripheral circuitry formation are provided. Strips of charge storage material elongated in a column direction across the surface of a substrate with strips of tunnel dielectric material therebetween are formed. The strips of charge storage material can include multiple layers of charge storage material to form composite charge storage structures in one embodiment. After forming isolation trenches in the substrate between active areas below the strips of charge storage material, spacer-assisted patterning is used to form a pattern at the memory array region. Strips of photoresist are patterned over a portion of the pattern at the memory array. Photoresist is also applied at the peripheral circuitry region.
    Type: Grant
    Filed: April 2, 2008
    Date of Patent: September 22, 2009
    Assignee: SanDisk Corporation
    Inventors: Tuan Pham, Takashi Orimoto, Masaaki Higashitani, James Kai, George Matamis
  • Patent number: 7582529
    Abstract: Non-volatile semiconductor memory devices with dual control gate memory cells and methods of forming the same using integrated peripheral circuitry formation are provided. Strips of charge storage material elongated in a row direction across the surface of a substrate with strips of tunnel dielectric material therebetween are formed. Forming the strips defines the dimension of the resulting charge storage structures in the column direction. The strips of charge storage material can include multiple layers of charge storage material to form composite charge storage structures in one embodiment. Strips of control gate material are formed between strips of charge storage material adjacent in the column direction. The strips of charge storage and control gate material are divided along their lengths in the row direction as part of forming isolation trenches and columns of active areas.
    Type: Grant
    Filed: April 2, 2008
    Date of Patent: September 1, 2009
    Assignee: SanDisk Corporation
    Inventors: George Matamis, Takashi Orimoto, Masaaki Higashitani, James Kai, Tuan Pham
  • Publication number: 20090189211
    Abstract: Non-volatile semiconductor memory devices with dual control gate memory cells and methods of forming are provided. A charge storage layer is etched into strips extending across a substrate surface in a row direction with a tunnel dielectric layer therebetween. The resulting strips may be continuous in the row direction or may comprise individual charge storage regions if already divided along their length in the row direction. A second layer of dielectric material is formed along the sidewalls of the strips and over the tunnel dielectric layer in the spaces therebetween. The second layer is etched into regions overlaying the tunnel dielectric layer in the spaces between strips. An intermediate dielectric layer is formed along exposed portions of the sidewalls of the strips and over the second dielectric layer in the spaces therebetween. A layer of control gate material is deposited in the spaces between strips.
    Type: Application
    Filed: January 25, 2008
    Publication date: July 30, 2009
    Inventors: Takashi Orimoto, George Matamis, 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: 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: 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: 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
  • Patent number: 7494870
    Abstract: A string of nonvolatile memory cells are connected together by source/drain regions that include an inversion layer created by fixed charge in an overlying layer. Control gates extend between floating gates so that two control gates couple to a floating gate. A fixed charge layer may be formed by plasma nitridation.
    Type: Grant
    Filed: January 24, 2007
    Date of Patent: February 24, 2009
    Assignee: SanDisk Corporation
    Inventors: Henry Chien, George Matamis, Takashi Orimoto, James Kai
  • Patent number: 7495282
    Abstract: A string of nonvolatile memory cells are connected together by source/drain regions that include an inversion layer created by fixed charge in an overlying layer. Control gates extend between floating gates so that two control gates couple to a floating gate. A fixed charge layer may be formed by plasma nitridation.
    Type: Grant
    Filed: January 24, 2007
    Date of Patent: February 24, 2009
    Assignee: SanDisk Corporation
    Inventors: Takashi Orimoto, James Kai, Henry Chien, George Matamis
  • Publication number: 20080318381
    Abstract: High density semiconductor devices and methods of fabricating the same are disclosed. Spacer fabrication techniques are utilized to form circuit elements having reduced feature sizes, which may be smaller than the smallest lithographically resolvable element size of the process being used. A first set of spacers may be processed to provide planar and parallel sidewalls. A second set of spacers may be formed on planar and parallel sidewalls of the first set of spacers. The second set of spacers serve as a mask to form one or more circuit elements in a layer beneath the second set of spacers. The steps according to embodiments of the invention allow a recursive spacer technique to be used which results in robust, evenly spaced, spacers to be formed and used as masks for the circuit elements.
    Type: Application
    Filed: June 20, 2007
    Publication date: December 25, 2008
    Inventors: George Matamis, James Kai, Takashi Orimoto, Nima Mokhlesi
  • Publication number: 20080268596
    Abstract: Non-volatile semiconductor memory devices with dual control gate memory cells and methods of forming the same using integrated select and peripheral circuitry formation are provided. Strips of charge storage material elongated in a column direction across the surface of a substrate with strips of tunnel dielectric material therebetween are formed. The strips of charge storage material can include multiple layers of charge storage material to form composite charge storage structures in one embodiment. After forming isolation trenches in the substrate between active areas below the strips of charge storage material, spacer-assisted patterning is used to form a pattern at the memory array region. Strips of photoresist are patterned over a portion of the pattern at the memory array. Photoresist is also applied at the peripheral circuitry region.
    Type: Application
    Filed: April 2, 2008
    Publication date: October 30, 2008
    Inventors: Tuan Pham, Takashi Orimoto, Masaaki Higashitani, James Kai, George Matamis
  • Patent number: 7444221
    Abstract: A vehicle braking force control apparatus detects a period of time from when a braking force of a brake device is cancelled until a vehicle body speed in the backwards direction of a vehicle on a hill reaches a predetermined state, determines a brake output according to the detected period of time, and controls braking pressure according to the determined brake output. The period of time depends on the gradient of the hill. Therefore, by determining the brake output according to this period of time, braking force control according to the gradient of the hill is made possible even at an extremely slow speed at which the vehicle speed is undetectable.
    Type: Grant
    Filed: November 3, 2004
    Date of Patent: October 28, 2008
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Noritaka Yamada, Takashi Orimoto
  • Publication number: 20080248622
    Abstract: Non-volatile semiconductor memory devices with dual control gate memory cells and methods of forming the same using integrated peripheral circuitry formation are provided. Strips of charge storage material elongated in a row direction across the surface of a substrate with strips of tunnel dielectric material therebetween are formed. Forming the strips defines the dimension of the resulting charge storage structures in the column direction. The strips of charge storage material can include multiple layers of charge storage material to form composite charge storage structures in one embodiment. Strips of control gate material are formed between strips of charge storage material adjacent in the column direction. The strips of charge storage and control gate material are divided along their lengths in the row direction as part of forming isolation trenches and columns of active areas.
    Type: Application
    Filed: April 2, 2008
    Publication date: October 9, 2008
    Inventors: George Matamis, Takashi Orimoto, Masaaki Higashitani, James Kai, Tuan Pham