Patents by Inventor Andrew J. Walker

Andrew J. Walker 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: 11329048
    Abstract: A DRAM memory cell and memory cell array incorporating a metal silicide bit line buried within a doped portion of a semiconductor substrate and a vertical semiconductor structure electrically connected with a memory element such as a capacitive memory element. The buried metal silicide layer functions as a bit buried bit line which can provide a bit line voltage to the capacitive memory element via the vertical transistor structure. The buried metal silicide layer can be formed by allotaxy or mesotaxy. The vertical semiconductor structure can be formed by epitaxially growing a semiconductor material on an etched surface of the doped portion of the semiconductor substrate.
    Type: Grant
    Filed: March 24, 2020
    Date of Patent: May 10, 2022
    Assignee: Integrated Silicon Solution, (Cayman) Inc.
    Inventors: Andrew J. Walker, Dafna Beery, Peter Cuevas, Amitay Levi
  • Patent number: 11302586
    Abstract: A structure for providing an inverter circuit employing two vertical transistor structures formed on a semiconductor substrate. The vertical semiconductor structures each include a semiconductor pillar structure and a surrounding gate dielectric. A gate structure is formed to at least partially surround the first and second vertical transistor structures. The semiconductor substrate is formed into first and section regions that are separated by a dielectric isolation structure. The first region includes a P+ doped portion and an N+ doped portion, and the second region includes an N+ doped portion and a P+ doped portion. The N+ and P+ doped portions of the first and second regions can be arranged such that the N+ doped portion of the first region is adjacent to the P+ doped portion of the second region, and the P+ doped portion of the first region is adjacent to the N+ doped portion of the second region.
    Type: Grant
    Filed: March 31, 2020
    Date of Patent: April 12, 2022
    Assignee: Integrated Silicon Solution, (Cayman) Inc.
    Inventors: Amitay Levi, Dafna Beery, Andrew J. Walker
  • Patent number: 11302697
    Abstract: A dynamic random access memory element that includes a vertical semiconductor transistor element formed on a substrate and electrically connected with a memory element such as a capacitive memory element. The memory element is located above the semiconductor substrate such that the vertical transistor is between the memory element and the substrate. The vertical semiconductor transistor is formed on a heavily doped region of the substrate that is separated from other portions of the substrate by a dielectric isolation layer. The heavily doped region of the semiconductor substrate provides electrical connection between the vertical transistor structure and a bit line. The dynamic random access memory element also includes a word line that includes an electrically conductive gate layer that is separated from the semiconductor pillar by a gate dielectric layer.
    Type: Grant
    Filed: January 28, 2020
    Date of Patent: April 12, 2022
    Assignee: Integrated Silicon Solution, (Cayman) Inc.
    Inventors: Andrew J. Walker, Dafna Beery, Peter Cuevas, Amitay Levi
  • Patent number: 11222970
    Abstract: A transistor structure, according to one embodiment, includes: an epitaxially grown vertical channel, a word line which surrounds a middle portion of the vertical channel, and a p-MTJ sensor coupled to a first end of the vertical channel. The second side of the vertical channel is opposite the first side of the vertical channel along a plane perpendicular to a deposition direction. A magnetic device, according to another embodiment, includes: a plurality of transistor structures, each of the transistor structures comprising: an epitaxially grown vertical channel, a word line which surrounds a middle portion of the vertical channel, and a p-MTJ sensor coupled to a first end of the vertical channel.
    Type: Grant
    Filed: December 28, 2017
    Date of Patent: January 11, 2022
    Assignee: Integrated Silicon Solution, (Cayman) Inc.
    Inventors: Kuk-Hwan Kim, Dafna Beery, Amitay Levi, Andrew J. Walker
  • Publication number: 20210391386
    Abstract: A vertical transistor structure having a metal gate wordline. The vertical transistor structure can include an epitaxially grown semiconductor column surrounded by a thin gate dielectric layer. A gate structure can surround the semiconductor column and the gate dielectric layer. The device can include first and second dielectric layers and an electrically conductive metal layer located between the first and second dielectric layers. The electrically conductive metal of the gate structure can be tungsten (W). In addition, a thin layer of Ti or TiN can be formed between the metal gate layer and the first and second dielectric layers and the gate dielectric layer. The metal gate layer can be formed with or without the use of a sacrificial layer.
    Type: Application
    Filed: June 10, 2020
    Publication date: December 16, 2021
    Inventors: Dafna Beery, Peter Cuevas, Amitay Levi, Andrew J. Walker
  • Publication number: 20210305105
    Abstract: A structure for providing an inverter circuit employing two vertical transistor structures formed on a semiconductor substrate. The vertical semiconductor structures each include a semiconductor pillar structure and a surrounding gate dielectric. A gate structure is formed to at least partially surround the first and second vertical transistor structures. The semiconductor substrate is formed into first and section regions that are separated by a dielectric isolation structure. The first region includes a P+ doped portion and an N+ doped portion, and the second region includes an N+ doped portion and a P+ doped portion. The N+ and P+ doped portions of the first and second regions can be arranged such that the N+ doped portion of the first region is adjacent to the P+ doped portion of the second region, and the P+ doped portion of the first region is adjacent to the N+ doped portion of the second region.
    Type: Application
    Filed: March 31, 2020
    Publication date: September 30, 2021
    Inventors: Amitay Levi, Dafna Beery, Andrew J. Walker
  • Publication number: 20210305256
    Abstract: A DRAM memory cell and memory cell array incorporating a metal silicide bit line buried within a doped portion of a semiconductor substrate and a vertical semiconductor structure electrically connected with a memory element such as a capacitive memory element. The buried metal silicide layer functions as a bit buried bit line which can provide a bit line voltage to the capacitive memory element via the vertical transistor structure. The buried metal silicide layer can be formed by allotaxy or mesotaxy. The vertical semiconductor structure can be formed by epitaxially growing a semiconductor material on an etched surface of the doped portion of the semiconductor substrate.
    Type: Application
    Filed: March 24, 2020
    Publication date: September 30, 2021
    Inventors: Andrew J. Walker, Dafna Beery, Peter Cuevas, Amitay Levi
  • Publication number: 20210233913
    Abstract: A dynamic random access memory element that includes a vertical semiconductor transistor element formed on a substrate and electrically connected with a memory element such as a capacitive memory element. The memory element is located above the semiconductor substrate such that the vertical transistor is between the memory element and the substrate. The vertical semiconductor transistor is formed on a heavily doped region of the substrate that is separated from other portions of the substrate by a dielectric isolation layer. The heavily doped region of the semiconductor substrate provides electrical connection between the vertical transistor structure and a bit line. The dynamic random access memory element also includes a word line that includes an electrically conductive gate layer that is separated from the semiconductor pillar by a gate dielectric layer.
    Type: Application
    Filed: January 28, 2020
    Publication date: July 29, 2021
    Inventors: Andrew J. Walker, Dafna Beery, Peter Cuevas, Amitay Levi
  • Publication number: 20210217814
    Abstract: A magnetic memory structure that includes a two-terminal resistive memory element electrically connected with a selector structure. The selector structure includes a semiconductor pillar structure formed on a semiconductor substrate. The selector structure is surrounded by a gate dielectric layer, and the semiconductor pillar structure and gate dielectric layer are surrounded by an electrically conductive gate structure. The semiconductor pillar has first and second dimensions in a plane parallel with the surface of the semiconductor substrate that are unequal with one another. The semiconductor pillar structure can have a cross-section parallel with the semiconductor substrate surface that is in the shape of a: rectangle; oval elongated polygon, etc. The length of the longer dimension can be adjusted to provide a desired amount of current though the semiconductor pillar structure to drive the two-terminal resistive memory element.
    Type: Application
    Filed: January 9, 2020
    Publication date: July 15, 2021
    Inventors: Andrew J. Walker, Dafna Beery, Peter Cuevas, Amitay Levi
  • Publication number: 20210090626
    Abstract: A magnetic memory array having an epitaxially grown vertical semiconductor selector connected with a two terminal resistive switching memory element via a bottom electrode such as TaN. An electrically conductive contact such as tungsten (W) or TaN can be included between the vertical semiconductor channel and the TaN bottom electrode. The electrically conductive contact and the TaN bottom electrode can both be formed by a damascene process wherein an opening is formed in an oxide layer and a metal is deposited into the opening. A chemical mechanical polishing process can then be performed to remove portions of the metal that extend out of the opening in the oxide layer over the oxide surface.
    Type: Application
    Filed: November 15, 2019
    Publication date: March 25, 2021
    Inventors: Dafna Beery, Amitay Levi, Andrew J. Walker
  • Patent number: 10957370
    Abstract: A magnetic memory array having an epitaxially grown vertical semiconductor selector connected with a two terminal resistive switching memory element via a bottom electrode such as TaN. An electrically conductive contact such as tungsten (W) or TaN can be included between the vertical semiconductor channel and the TaN bottom electrode. The electrically conductive contact and the TaN bottom electrode can both be formed by a damascene process wherein an opening is formed in an oxide layer and a metal is deposited into the opening. A chemical mechanical polishing process can then be performed to remove portions of the metal that extend out of the opening in the oxide layer over the oxide surface.
    Type: Grant
    Filed: November 15, 2019
    Date of Patent: March 23, 2021
    Assignee: SPIN MEMORY, INC.
    Inventors: Dafna Beery, Amitay Levi, Andrew J. Walker
  • Publication number: 20210065760
    Abstract: A magnetic memory array having an epitaxially grown vertical semiconductor selector connected with a memory element via a bottom electrode such as TaN. An electrically conductive contact such as tungsten (W) or TaN can be included between the vertical semiconductor channel and the TaN bottom electrode. The electrically conductive contact and the TaN bottom electrode can both be formed by a damascene process wherein an opening is formed in an oxide layer and a metal is deposited into the opening. A chemical mechanical polishing process can then be performed to remove portions of the metal that extend out of the opening in the oxide layer over the oxide surface.
    Type: Application
    Filed: August 29, 2019
    Publication date: March 4, 2021
    Inventors: Dafna Beery, Amitay Levi, Andrew J. Walker
  • Patent number: 10937479
    Abstract: A magnetic memory array having an epitaxially grown vertical semiconductor selector connected with a memory element via a bottom electrode such as TaN. An electrically conductive contact such as tungsten (W) or TaN can be included between the vertical semiconductor channel and the TaN bottom electrode. The electrically conductive contact and the TaN bottom electrode can both be formed by a damascene process wherein an opening is formed in an oxide layer and a metal is deposited into the opening. A chemical mechanical polishing process can then be performed to remove portions of the metal that extend out of the opening in the oxide layer over the oxide surface.
    Type: Grant
    Filed: August 29, 2019
    Date of Patent: March 2, 2021
    Assignee: SPIN MEMORY, INC.
    Inventors: Dafna Beery, Amitay Levi, Andrew J. Walker
  • Patent number: 10930703
    Abstract: A method for crystalized silicon structures from amorphous structures in a magnetic memory array, wherein the temperature needed to crystalize the amorphous silicon is lower than the temperature budget of the memory element so as to avoid damage to the memory element. An amorphous silicon is deposited, followed by a layer of Ti or Co. An annealing process is then performed which causes the Ti or Co to form TiSi2 or CoSi2 and also causes the underlying amorphous silicon to crystallize.
    Type: Grant
    Filed: December 31, 2018
    Date of Patent: February 23, 2021
    Assignee: SPIN MEMORY, INC.
    Inventors: Kuk-Hwan Kim, Dafna Beery, Marcin Gajek, Michail Tzoufras, Kadriye Deniz Bozdag, Eric Michael Ryan, Satoru Araki, Andrew J. Walker
  • Patent number: 10916582
    Abstract: According to one embodiment, a method includes forming a first insulative layer above a bottom surface of a groove and along inner sidewalls thereof, forming a source line layer within the groove of the substrate, forming a first dielectric layer on outer sides of a middle portion of the source line layer, forming a buffer layer on outer sides of the first dielectric layer, forming a gate terminal above the source line layer, forming a gate dielectric layer between the source line layer and the gate terminal and on outer sides of the lower portion of the gate terminal, forming a drain terminal including strained Si on outer sides of the first dielectric layer, and forming a relaxed buffer layer on outer sides of the upper portion of the source line layer and outer sides of the drain terminal, with the gate terminal extending beyond the relaxed buffer layer thickness.
    Type: Grant
    Filed: December 30, 2017
    Date of Patent: February 9, 2021
    Assignee: SPIN MEMORY, INC.
    Inventors: Kuk-Hwan Kim, Dafna Beery, Amitay Levi, Andrew J. Walker
  • Patent number: 10854255
    Abstract: A magnetic memory array having a source-plane electrically connected with an array of channel selectors in two-dimensions. The array of channel selectors can be arranged in rows and columns with both the rows and columns being electrically connected with a source-plane. A memory element such as a two terminal resistive switching memory element can be electrically connected with each of the channel selectors. The source-plane can include a doped region formed in a surface of a semiconductor substrate and may also include an electrically conductive layer formed on the doped region. The use of such a planar, two-dimensional source-plane allows for greatly increased data density by eliminating the need to form separate source-line source lines for individual rows of channel selectors.
    Type: Grant
    Filed: November 21, 2019
    Date of Patent: December 1, 2020
    Assignee: SPIN MEMORY, INC.
    Inventors: Adrian E. Ong, Andrew J. Walker, Dafna Beery
  • Patent number: 10840298
    Abstract: A magnetic memory array having a source-plane electrically connected with an array of channel selectors in two-dimensions. The array of channel selectors can be arranged in rows and columns with both the rows and columns being electrically connected with a source-plane. A magnetic memory element such as a magnetic tunnel junction element can be electrically connected with each of the channel selectors. The source-plane can include a doped region formed in a surface of a semiconductor substrate and may also include an electrically conductive layer formed on the doped region. The use of such a planar, two-dimensional source-plane allows for greatly increased data density by eliminating the need to form separate source-line source lines for individual rows of channel selectors.
    Type: Grant
    Filed: June 28, 2019
    Date of Patent: November 17, 2020
    Assignee: SPIN MEMORY, INC.
    Inventors: Adrian E. Ong, Andrew J. Walker, Dafna Beery
  • Patent number: 10686009
    Abstract: A method for forming three-dimensional magnetic memory arrays by forming crystalized silicon structures from amorphous structures in the magnetic memory array, wherein the temperature needed to crystalize the amorphous silicon is lower than the temperature budget of the memory element so as to avoid damage to the memory element. An amorphous silicon is deposited, followed by a layer of Ti or Co. An annealing process is then performed which causes the Ti or Co to form TiSi2 or CoSi2 and also causes the underlying amorphous silicon to crystallize.
    Type: Grant
    Filed: December 31, 2018
    Date of Patent: June 16, 2020
    Assignee: SPIN MEMORY, INC.
    Inventors: Kuk-Hwan Kim, Dafna Beery, Marcin Gajek, Michail Tzoufras, Kadriye Deniz Bozdag, Eric Michael Ryan, Satoru Araki, Andrew J. Walker
  • Patent number: 10658425
    Abstract: A method of forming a transistor, according to one embodiment, includes: forming an doped material, depositing an oxide layer on the doped material, depositing a conducting layer on the oxide layer, patterning the conducting layer to form at least two word lines, depositing a nitride layer above the at least two word lines, defining at least two hole regions, at each of the defined hole regions, etching down to the doped material through each of the respective word lines, thereby creating at least two holes, depositing a gate dielectric layer on the nitride layer and in the at least two holes, depositing a protective layer on the gate dielectric layer, etching in each of the at least two holes down to the doped material, and removing a remainder of the protective layer.
    Type: Grant
    Filed: December 31, 2018
    Date of Patent: May 19, 2020
    Assignee: SPIN MEMORY, INC.
    Inventors: Kuk-Hwan Kim, Dafna Beery, Amitay Levi, Andrew J. Walker
  • Publication number: 20200127052
    Abstract: A memory array for data recording that includes a selector transistor electrically connected with a two terminal resistive memory element such as a magnetic tunnel junction (MTJ) element. The selector transistor comprises a semiconductor column formed by selective epitaxial growth on a semiconductor surface. The semiconductor column is at least partially surrounded by a gate dielectric layer and an electrically conductive gate structure arranged such that the gate dielectric is between the electrically conducive gate structure and the semiconductor column. The selective epitaxial growth of the semiconductor column allows the semiconductor column to have a very low electrical resistance in an “on” state which allows the selector transistor to provide a high electrical current to the two terminal resistive memory element for reliable switching during data writing.
    Type: Application
    Filed: December 18, 2019
    Publication date: April 23, 2020
    Inventors: Andrew J. Walker, Dafna Beery, Peter Cuevas, Amitay Levi