Patents by Inventor Kento Kitamura

Kento Kitamura 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).

  • Patent number: 10008570
    Abstract: The contact area between a source strap structure of a buried source layer and semiconductor channels within memory structures can be increased by laterally expanding a source-level volume in which the memory stack structures are formed. In one embodiment, sacrificial semiconductor pedestals can be formed in source-level memory openings prior to formation of a vertically alternating stack of insulating layers and sacrificial material layers. Memory openings can include bulging portions formed by removal of the sacrificial semiconductor pedestals. Memory stack structures can be formed with a greater sidewall surface area in the bulging portions to provide a greater contact area with the source strap structure. Alternatively, bottom portions of memory openings can be expanded selective to upper portions during, or after, formation of the memory openings to provide bulging portions and to increase the contact area with the source strap structure.
    Type: Grant
    Filed: March 14, 2017
    Date of Patent: June 26, 2018
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Jixin Yu, Kento Kitamura, Tong Zhang, Chun Ge, Yanli Zhang, Satoshi Shimizu, Yasuo Kasagi, Hiroyuki Ogawa, Daxin Mao, Kensuke Yamaguchi, Johann Alsmeier, James Kai
  • Patent number: 9991282
    Abstract: A layer stack including a lower semiconductor layer, a lower dielectric layer, and a spacer material layer is formed over a semiconductor substrate, and the spacer material layer is patterned to form spacer line structures. An upper dielectric layer and an upper semiconductor layer are formed, followed by formation of an alternating stack of insulating layers and spacer material layers. Memory stack structures are formed through the alternating stack, the upper semiconductor layer, and the dielectric material layer. The upper semiconductor layer, the upper dielectric layer, and the lower semiconductor layer can be patterned to form a buried source layer and at least one passive device. Each passive device can include a lower semiconductor plate, a dielectric material plate, and an upper semiconductor plate. Each passive device can be a resistor or a capacitor.
    Type: Grant
    Filed: December 15, 2017
    Date of Patent: June 5, 2018
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Satoshi Shimizu, Hiroyuki Ogawa, Yasuo Kasagi, Kento Kitamura
  • Publication number: 20180151589
    Abstract: A layer stack including a lower semiconductor layer, a lower dielectric layer, and a spacer material layer is formed over a semiconductor substrate, and the spacer material layer is patterned to form spacer line structures. An upper dielectric layer and an upper semiconductor layer are formed, followed by formation of an alternating stack of insulating layers and spacer material layers. Memory stack structures are formed through the alternating stack, the upper semiconductor layer, and the dielectric material layer. The upper semiconductor layer, the upper dielectric layer, and the lower semiconductor layer can be patterned to form a buried source layer and at least one passive device. Each passive device can include a lower semiconductor plate, a dielectric material plate, and an upper semiconductor plate. Each passive device can be a resistor or a capacitor.
    Type: Application
    Filed: December 15, 2017
    Publication date: May 31, 2018
    Inventors: Satoshi SHIMIZU, Hiroyuki OGAWA, Yasuo KASAGI, Kento KITAMURA
  • Publication number: 20180122906
    Abstract: The contact area between a source strap structure of a buried source layer and semiconductor channels within memory structures can be increased by laterally expanding a source-level volume in which the memory stack structures are formed. In one embodiment, sacrificial semiconductor pedestals can be formed in source-level memory openings prior to formation of a vertically alternating stack of insulating layers and sacrificial material layers. Memory openings can include bulging portions formed by removal of the sacrificial semiconductor pedestals. Memory stack structures can be formed with a greater sidewall surface area in the bulging portions to provide a greater contact area with the source strap structure. Alternatively, bottom portions of memory openings can be expanded selective to upper portions during, or after, formation of the memory openings to provide bulging portions and to increase the contact area with the source strap structure.
    Type: Application
    Filed: March 14, 2017
    Publication date: May 3, 2018
    Inventors: Jixin YU, Kento KITAMURA, Tong ZHANG, Chun GE, Yanli ZHANG, Satoshi SHIMIZU, Yasuo KASAGI, Hiroyuki OGAWA, Daxin MAO, Kensuke YAMAGUCHI, Johann ALSMEIER, James KAI
  • Patent number: 9876031
    Abstract: A layer stack including a lower semiconductor layer, a lower dielectric layer, and a spacer material layer is formed over a semiconductor substrate, and the spacer material layer is patterned to form spacer line structures. An upper dielectric layer and an upper semiconductor layer are formed, followed by formation of an alternating stack of insulating layers and spacer material layers. Memory stack structures are formed through the alternating stack, the upper semiconductor layer, and the dielectric material layer. The upper semiconductor layer, the upper dielectric layer, and the lower semiconductor layer can be patterned to form a buried source layer and at least one passive device. Each passive device can include a lower semiconductor plate, a dielectric material plate, and an upper semiconductor plate. Each passive device can be a resistor or a capacitor.
    Type: Grant
    Filed: January 30, 2017
    Date of Patent: January 23, 2018
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Satoshi Shimizu, Hiroyuki Ogawa, Yasuo Kasagi, Kento Kitamura