Patents by Inventor Murshed CHOWDHURY

Murshed CHOWDHURY 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: 10490568
    Abstract: A three-dimensional memory device including self-aligned drain select level electrodes is provided. Memory stack structures extend through an alternating stack of insulating layers and spacer material layers. Each of the memory stack structures includes a memory film and a memory level channel portion. Drain select level channel portions are formed over the memory level channel portions with respective lateral shifts with respect to underlying memory stack structures. The direction of lateral shifts alternates from row to row for each row of drain select level channel portions. Drain select level gate dielectrics and drain select level gate electrodes are formed on the drain select level channel portions. Each drain select level gate electrode controls two rows of drain select level channel portions, and is laterally spaced from neighboring drain select level gate electrodes.
    Type: Grant
    Filed: March 21, 2018
    Date of Patent: November 26, 2019
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: James Kai, Murshed Chowdhury, Jin Liu, Johann Alsmeier
  • Patent number: 10490569
    Abstract: Multiple tier structures are stacked over a substrate. Each tier structure includes an alternating stack of insulating layers and sacrificial material layers and a retro-stepped dielectric material portion overlying the alternating stack. Multiple types of openings are formed concurrently during formation of each tier structure. Openings concurrently formed through each tier structure can include at least two types of openings that may be selected from through-tier memory openings, through-tier support openings, and through-tier staircase-region openings. Each through-tier opening is filled with a respective through-tier sacrificial opening fill structure. Stacks of through-tier sacrificial opening fill structures can be removed in stages to form various device components, which include memory stack structures, support pillar structures, and staircase-region contact via structures.
    Type: Grant
    Filed: June 27, 2018
    Date of Patent: November 26, 2019
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Mitsuteru Mushiga, Hisakazu Otoi, Kensuke Yamaguchi, James Kai, Zhixin Cui, Murshed Chowdhury, Johann Alsmeier, Tong Zhang
  • Publication number: 20190355663
    Abstract: A semiconductor structure includes a semiconductor device, an overlying silicon nitride diffusion barrier layer, and an interconnect structure extending through the silicon nitride diffusion barrier layer. The interconnect structure includes a titanium diffusion barrier structure in contact with the silicon nitride diffusion barrier layer to form a continuous hydrogen diffusion barrier structure.
    Type: Application
    Filed: May 17, 2018
    Publication date: November 21, 2019
    Inventors: Masatoshi NISHIKAWA, Akio NISHIDA, Murshed CHOWDHURY, Takahito FUJITA, Kiyokazu SHISHIDO, Hiroyuki OGAWA
  • Patent number: 10461163
    Abstract: A three-dimensional memory device includes an alternating stack of insulating layers and electrically conductive layers located over a substrate. Memory stack structures are located in a memory array region, each of which includes a memory film and a vertical semiconductor channel. Contact via structures located in the terrace region and contact a respective one of the electrically conductive layers. Each of the electrically conductive layers has a respective first thickness throughout the memory array region and includes a contact portion having a respective second thickness that is greater than the respective first thickness within a terrace region. The greater thickness of the contact portion prevents an etch-through during formation of contact via cavities for forming the contact via structures.
    Type: Grant
    Filed: November 15, 2017
    Date of Patent: October 29, 2019
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Senaka Krishna Kanakamedala, Yoshihiro Kanno, Raghuveer S. Makala, Yanli Zhang, Jin Liu, Murshed Chowdhury, Yao-Sheng Lee
  • Patent number: 10453854
    Abstract: A three-dimensional memory device includes an alternating stack of insulating layers and electrically conductive layers located over a substrate. Memory stack structures are located in a memory array region, each of which includes a memory film and a vertical semiconductor channel. Contact via structures located in the terrace region and contact a respective one of the electrically conductive layers. Each of the electrically conductive layers has a respective first thickness throughout the memory array region and includes a contact portion having a respective second thickness that is greater than the respective first thickness within a terrace region. The greater thickness of the contact portion prevents an etch-through during formation of contact via cavities for forming the contact via structures.
    Type: Grant
    Filed: November 15, 2017
    Date of Patent: October 22, 2019
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Yoshihiro Kanno, Senaka Krishna Kanakamedala, Raghuveer S. Makala, Yanli Zhang, Jin Liu, Murshed Chowdhury
  • Publication number: 20190280002
    Abstract: A first-tier structure including a first alternating stack of first insulating layers and first spacer material layers is formed over a substrate. First-tier memory openings and at least one type of first-tier contact openings can be formed simultaneously employing a same anisotropic etch process. The first-tier contact openings formed over stepped surfaces of the first alternating stack may extend through the first alternating stack, or may stop on the stepped surfaces. Sacrificial first-tier opening fill portions are formed in the first-tier openings, and a second-tier structure can be formed over the first-tier structure. Memory openings including volumes of the first-tier memory openings are formed through the multi-tier structure, and memory stack structures are formed in the memory openings. Various contact openings are formed through the multi-tier structure, and various contact via structures are formed in the contact openings.
    Type: Application
    Filed: June 27, 2018
    Publication date: September 12, 2019
    Inventors: James Kai, Zhixin Cui, Murshed Chowdhury, Johann Alsmeier, Tong Zhang
  • Publication number: 20190280003
    Abstract: Multiple tier structures are stacked over a substrate. Each tier structure includes an alternating stack of insulating layers and sacrificial material layers and a retro-stepped dielectric material portion overlying the alternating stack. Multiple types of openings are formed concurrently during formation of each tier structure. Openings concurrently formed through each tier structure can include at least two types of openings that may be selected from through-tier memory openings, through-tier support openings, and through-tier staircase-region openings. Each through-tier opening is filled with a respective through-tier sacrificial opening fill structure. Stacks of through-tier sacrificial opening fill structures can be removed in stages to form various device components, which include memory stack structures, support pillar structures, and staircase-region contact via structures.
    Type: Application
    Filed: June 27, 2018
    Publication date: September 12, 2019
    Inventors: Mitsuteru Mushiga, Hisakazu Otoi, Kensuke Yamaguchi, James Kai, Zhixin Cui, Murshed Chowdhury, Johann Alsmeier, Tong Zhang
  • Patent number: 10388666
    Abstract: A first-tier structure including a first alternating stack of first insulating layers and first spacer material layers is formed over a substrate. First-tier memory openings and at least one type of first-tier contact openings can be formed simultaneously employing a same anisotropic etch process. The first-tier contact openings formed over stepped surfaces of the first alternating stack may extend through the first alternating stack, or may stop on the stepped surfaces. Sacrificial first-tier opening fill portions are formed in the first-tier openings, and a second-tier structure can be formed over the first-tier structure. Memory openings including volumes of the first-tier memory openings are formed through the multi-tier structure, and memory stack structures are formed in the memory openings. Various contact openings are formed through the multi-tier structure, and various contact via structures are formed in the contact openings.
    Type: Grant
    Filed: June 27, 2018
    Date of Patent: August 20, 2019
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: James Kai, Zhixin Cui, Murshed Chowdhury, Johann Alsmeier, Tong Zhang
  • Patent number: 10355009
    Abstract: A first-tier structure including a first alternating stack of first insulating layers and first spacer material layers is formed over a substrate. First-tier memory openings and at least one type of first-tier contact openings can be formed simultaneously employing a same anisotropic etch process. The first-tier contact openings formed over stepped surfaces of the first alternating stack may extend through the first alternating stack, or may stop on the stepped surfaces. Sacrificial first-tier opening fill portions are formed in the first-tier openings, and a second-tier structure can be formed over the first-tier structure. Memory openings including volumes of the first-tier memory openings are formed through the multi-tier structure, and memory stack structures are formed in the memory openings. Various contact openings are formed through the multi-tier structure, and various contact via structures are formed in the contact openings.
    Type: Grant
    Filed: June 27, 2018
    Date of Patent: July 16, 2019
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: James Kai, Zhixin Cui, Murshed Chowdhury, Johann Alsmeier, Tong Zhang
  • Publication number: 20190148392
    Abstract: A three-dimensional memory device includes an alternating stack of insulating layers and electrically conductive layers located over a substrate. Memory stack structures are located in a memory array region, each of which includes a memory film and a vertical semiconductor channel. Contact via structures located in the terrace region and contact a respective one of the electrically conductive layers. Each of the electrically conductive layers has a respective first thickness throughout the memory array region and includes a contact portion having a respective second thickness that is greater than the respective first thickness within a terrace region. The greater thickness of the contact portion prevents an etch-through during formation of contact via cavities for forming the contact via structures.
    Type: Application
    Filed: November 15, 2017
    Publication date: May 16, 2019
    Inventors: Yoshihiro KANNO, Senaka Krishna KANAKAMEDALA, Raghuveer S. MAKALA, Yanli ZHANG, Jin LIU, Murshed CHOWDHURY
  • Publication number: 20190148506
    Abstract: A three-dimensional memory device includes an alternating stack of insulating layers and electrically conductive layers located over a substrate. Memory stack structures are located in a memory array region, each of which includes a memory film and a vertical semiconductor channel. Contact via structures located in the terrace region and contact a respective one of the electrically conductive layers. Each of the electrically conductive layers has a respective first thickness throughout the memory array region and includes a contact portion having a respective second thickness that is greater than the respective first thickness within a terrace region. The greater thickness of the contact portion prevents an etch-through during formation of contact via cavities for forming the contact via structures.
    Type: Application
    Filed: November 15, 2017
    Publication date: May 16, 2019
    Inventors: Senaka Krishna KANAKAMEDALA, Yoshihiro KANNO, Raghuveer S. MAKALA, Yanli ZHANG, Jin LIU, Murshed CHOWDHURY, Yao-Sheng LEE
  • Patent number: 10262945
    Abstract: A three-dimensional memory device includes driver transistors containing boron doped semiconductor active regions, device contact via structures in physical contact with the boron doped semiconductor active regions, the device contact via structures containing at least one of tantalum, tungsten, and cobalt, and a three-dimensional memory array located over the driver transistors and including an alternating stack of insulating layers and electrically conductive layers and memory structures vertically extending through the alternating stack.
    Type: Grant
    Filed: April 28, 2017
    Date of Patent: April 16, 2019
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Raghuveer S. Makala, Murshed Chowdhury, Keerti Shukla, Tomohisa Abe, Yao-Sheng Lee, James Kai
  • Patent number: 10224407
    Abstract: A trench having a uniform depth is provided in an upper portion of a semiconductor substrate. A continuous dielectric material layer is formed, which includes a gate dielectric that fills an entire volume of the trench. A gate electrode is formed over the gate dielectric such that the gate electrode overlies a center portion of the gate dielectric and does not overlie a first peripheral portion and a second peripheral portion of the gate dielectric that are located on opposing sides of the center portion of the gate dielectric. After formation of a dielectric gate spacer, a source extension region and a drain extension region are formed within the semiconductor substrate by doping respective portions of the semiconductor substrate.
    Type: Grant
    Filed: February 28, 2017
    Date of Patent: March 5, 2019
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Murshed Chowdhury, Andrew Lin, James Kai, Yanli Zhang, Johann Alsmeier
  • Patent number: 10224104
    Abstract: Two vertical NAND strings can share a common bit line by providing two pairs of drain select transistors. Channels of each vertical NAND string containing an adjoining pair of drain select transistors are incorporated into a respective vertical semiconductor channel, which is adjoined to a respective drain region which is connected to the common bit line. The drain select transistors have mismatched threshold voltages at each level such that each vertical NAND string includes a level at which a respective drain select transistor has a higher threshold voltage than a counterpart drain select transistor for the other vertical NAND string at the same level. By turning on three drain select transistors out of four, only one vertical NAND string can be activated while the common bit line is biased at a suitable bias voltage. A programming operation or a read operation can be performed only on the activated NAND string.
    Type: Grant
    Filed: March 23, 2016
    Date of Patent: March 5, 2019
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Murshed Chowdhury, Jin Liu, Yanli Zhang, Andrew Lin, Raghuveer S. Makala, Johann Alsmeier
  • Patent number: 10121794
    Abstract: An alternating stack of insulating layers and spacer material layers is formed over a semiconductor substrate. Memory openings are formed through the alternating stack. An optional silicon-containing epitaxial pedestal and a memory film are formed in each memory opening. After forming an opening through a bottom portion of the memory film within each memory opening, a germanium-containing semiconductor layer and a dielectric layer is formed in each memory opening. Employing the memory film and the dielectric layer as a crucible, a liquid phase epitaxy anneal is performed to convert the germanium-containing semiconductor layer into a germanium-containing epitaxial channel layer. A dielectric core and a drain region can be formed over the dielectric layer. The germanium-containing epitaxial channel layer is single crystalline, and can provide a higher charge carrier mobility than a polysilicon channel.
    Type: Grant
    Filed: September 29, 2016
    Date of Patent: November 6, 2018
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Marika Gunji-Yoneoka, Atsushi Suyama, Jayavel Pachamuthu, Tsuyoshi Hada, Daewung Kang, Murshed Chowdhury, James Kai, Hiro Kinoshita, Tomoyuki Obu, Luckshitha Suriyasena Liyanage
  • Publication number: 20180277567
    Abstract: An annular dielectric spacer can be formed at a level of a joint-level dielectric material layer between vertically neighboring pairs of alternating stacks of insulating layers and spacer material layers. After formation of a memory opening through multiple alternating stacks and formation of a memory film therein, an anisotropic etch can be performed to remove a horizontal bottom portion of the memory film. The annular dielectric spacer can protect underlying portions of the memory film during the anisotropic etch. In addition, a silicon nitride barrier may be employed to suppress hydrogen diffusion at an edge region of peripheral devices.
    Type: Application
    Filed: May 25, 2018
    Publication date: September 27, 2018
    Inventors: Tadashi Nakamura, Jin Liu, Kazuya Tokunaga, Marika Gunji-Yoneoka, Matthias Baenninger, Hiroyuki Kinoshita, Murshed Chowdhury, Jiyin Xu
  • Publication number: 20180248013
    Abstract: A trench having a uniform depth is provided in an upper portion of a semiconductor substrate. A continuous dielectric material layer is formed, which includes a gate dielectric that fills an entire volume of the trench. A gate electrode is formed over the gate dielectric such that the gate electrode overlies a center portion of the gate dielectric and does not overlie a first peripheral portion and a second peripheral portion of the gate dielectric that are located on opposing sides of the center portion of the gate dielectric. After formation of a dielectric gate spacer, a source extension region and a drain extension region are formed within the semiconductor substrate by doping respective portions of the semiconductor substrate.
    Type: Application
    Filed: February 28, 2017
    Publication date: August 30, 2018
    Inventors: Murshed CHOWDHURY, Andrew LIN, James KAI, Yanli ZHANG, Johann ALSMEIER
  • Publication number: 20180211970
    Abstract: A three-dimensional memory device including self-aligned drain select level electrodes is provided. Memory stack structures extend through an alternating stack of insulating layers and spacer material layers. Each of the memory stack structures includes a memory film and a memory level channel portion. Drain select level channel portions are formed over the memory level channel portions with respective lateral shifts with respect to underlying memory stack structures. The direction of lateral shifts alternates from row to row for each row of drain select level channel portions. Drain select level gate dielectrics and drain select level gate electrodes are formed on the drain select level channel portions. Each drain select level gate electrode controls two rows of drain select level channel portions, and is laterally spaced from neighboring drain select level gate electrodes.
    Type: Application
    Filed: March 21, 2018
    Publication date: July 26, 2018
    Inventors: James Kai, Murshed Chowdhury, Jin Liu, Johann Alsmeier
  • Patent number: 9991280
    Abstract: An annular dielectric spacer can be formed at a level of a joint-level dielectric material layer between vertically neighboring pairs of alternating stacks of insulating layers and spacer material layers. After formation of a memory opening through multiple alternating stacks and formation of a memory film therein, an anisotropic etch can be performed to remove a horizontal bottom portion of the memory film. The annular dielectric spacer can protect underlying portions of the memory film during the anisotropic etch. In addition, a silicon nitride barrier may be employed to suppress hydrogen diffusion at an edge region of peripheral devices.
    Type: Grant
    Filed: February 16, 2017
    Date of Patent: June 5, 2018
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Tadashi Nakamura, Jin Liu, Kazuya Tokunaga, Marika Gunji-Yoneoka, Matthias Baenninger, Hiroyuki Kinoshita, Murshed Chowdhury, Jiyin Xu, Dai Iwata, Hiroyuki Ogawa, Kazutaka Yoshizawa, Yasuaki Yonemochi
  • Publication number: 20180151497
    Abstract: A three-dimensional memory device includes driver transistors containing boron doped semiconductor active regions, device contact via structures in physical contact with the boron doped semiconductor active regions, the device contact via structures containing at least one of tantalum, tungsten, and cobalt, and a three-dimensional memory array located over the driver transistors and including an alternating stack of insulating layers and electrically conductive layers and memory structures vertically extending through the alternating stack.
    Type: Application
    Filed: April 28, 2017
    Publication date: May 31, 2018
    Inventors: Raghuveer S. MAKALA, Murshed CHOWDHURY, Keerti SHUKLA, Tomohisa ABE, Yao-Sheng LEE, James KAI