Patents by Inventor Sateesh KOKA

Sateesh KOKA 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: 20170047334
    Abstract: A monolithic three-dimensional memory device includes a first memory block containing a plurality of memory sub-blocks located on a substrate. Each memory sub-block includes a set of memory stack structures and a portion of alternating layers laterally surrounding the set of memory stack structures. The alternating layers include insulating layers and electrically conductive layers. A first portion of a neighboring pair of memory sub-blocks is laterally spaced from each other along a first horizontal direction by a backside contact via structure. A subset of the alternating layers contiguously extends between a second portion of the neighboring pair of memory sub-blocks through a gap in a bridge region between two portions of the backside contact via structure that are laterally spaced apart along a second horizontal direction to provide a connecting portion between the neighboring pair of memory sub-blocks.
    Type: Application
    Filed: August 11, 2015
    Publication date: February 16, 2017
    Inventors: Zhenyu Lu, Johann Alsmeier, Daxin Mao, Stephen Shi, Sateesh Koka, Raghuveer S. Makala, George Matamis, Yao-Sheng Lee, Chun Ge
  • Patent number: 9570455
    Abstract: A method of making a monolithic three dimensional NAND string including forming a stack of alternating layers of insulating first material and sacrificial second material different from the first material over a major surface of the substrate, forming a front side opening in the stack, forming at least one charge storage region in the front side opening and forming a tunnel dielectric layer over the at least one charge storage region in front side opening. The method also includes forming a semiconductor channel over the tunnel dielectric layer in the front side opening, forming a back side opening in the stack and selectively removing at least portions of the second material layers to form back side recesses between adjacent first material layers.
    Type: Grant
    Filed: November 25, 2014
    Date of Patent: February 14, 2017
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Rahul Sharangpani, Raghuveer S. Makala, Senaka Krishna Kanakamedala, Sateesh Koka, Yao-Sheng Lee, George Matamis
  • Publication number: 20160379989
    Abstract: A method of manufacturing a semiconductor structure includes forming a stack of alternating layers comprising insulating layers and spacer material layers over a semiconductor substrate, forming a memory opening through the stack, forming an aluminum oxide layer having a horizontal portion at a bottom of the memory opening and a vertical portion at least over a sidewall of the memory opening, where the horizontal portion differs from the vertical portion by at least one of structure or composition, and selectively etching the horizontal portion selective to the vertical portion.
    Type: Application
    Filed: June 24, 2015
    Publication date: December 29, 2016
    Inventors: Rahul SHARANGPANI, Sateesh KOKA, Raghuveer S. MAKALA, Srikanth RANGANATHAN, Mark JUANITAS, Johann ALSMEIER
  • Patent number: 9530785
    Abstract: A memory stack structure for a three-dimensional device includes an alternating stack of insulator layers and spacer material layers. A memory opening is formed through the alternating stack. A memory material layer, a tunneling dielectric layer, and a silicon oxide liner are formed in the memory opening. A sacrificial liner is subsequently formed over the tunneling dielectric layer. The layer stack is anisotropically etched to physically expose a semiconductor surface of the substrate underneath the memory opening. The sacrificial liner may be removed prior to, or after, the anisotropic etch. The silicon oxide liner is removed after the anisotropic etch. A semiconductor channel layer can be deposited directly on the tunneling dielectric layer as a single material layer without any interface therein.
    Type: Grant
    Filed: July 21, 2015
    Date of Patent: December 27, 2016
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Sateesh Koka, Zhenyu Lu, Wei Zhao, Ching-Huang Lu, Henry Chien, Yingda Dong, Raghuveer S. Makala, Somesh Peri, Rahul Sharangpani, George Matamis, Yuichi Ikezono, Hiroyuki Ogawa
  • Patent number: 9524977
    Abstract: Resistance of a semiconductor channel in three-dimensional memory stack structures can be reduced by forming a metal-semiconductor alloy region between a vertical semiconductor channel and a horizontal semiconductor channel located within a substrate. The metal-semiconductor alloy region can be formed by recessing a portion of the semiconductor material layer in the semiconductor substrate underneath a memory opening after formation of a memory film, selectively depositing a metallic material in the recess region, depositing a vertical semiconductor channel, and reacting the deposited metallic material with an adjacent portion of the semiconductor material layer and the vertical semiconductor channel. A sacrificial dielectric material layer can be formed on the memory film prior to the selective deposition of the metallic material.
    Type: Grant
    Filed: April 15, 2015
    Date of Patent: December 20, 2016
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Rahul Sharangpani, Raghuveer S. Makala, Sateesh Koka, Tomohiro Kubo, Junichi Ariyoshi, George Matamis
  • Patent number: 9515079
    Abstract: Blocking dielectric structures and/or thicker barrier metal films for preventing or reducing fluorine diffusion are provided. A blocking dielectric layer can be formed as an outer layer of a memory film in a memory stack structure extending through electrically insulating layers and sacrificial material layers. After formation of backside recesses by removal of the sacrificial material layers, dopants can be introduced into physically exposed portions of the blocking dielectric layer, for example, by plasma treatment or thermal treatment, to form silicon oxynitride regions which can reduce or prevent fluorine diffusion. Alternatively or additionally, a set of metal oxide blocking dielectric material portions can be formed in the backside recesses to retard or prevent fluorine diffusion. To minimize adverse impact on the electrically conductive layers formed in the backside recesses, the blocking dielectric material portions can be laterally recessed from a trench employed to form the backside recesses.
    Type: Grant
    Filed: June 26, 2015
    Date of Patent: December 6, 2016
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Sateesh Koka, Raghuveer S. Makala, Somesh Peri, Rahul Sharangpani, Yao-Sheng Lee, George Matamis, Wei Zhao
  • Patent number: 9496419
    Abstract: A memory film and a semiconductor channel can be formed within each memory opening that extends through a stack including an alternating plurality of insulator layers and sacrificial material layers. After formation of backside recesses through removal of the sacrificial material layers selective to the insulator layers, a ruthenium portion can be formed in each backside recess, and a polycrystalline conductive material portion can be formed on each ruthenium portion. Each ruthenium portion can be employed in lieu of a tungsten seed layer to function as a lower resistivity seed layer that enables subsequent deposition of a polycrystalline conductive material. The resulting electrically conductive lines can have a lower resistivity than conductive lines of comparable dimensions that employ tungsten seed layers.
    Type: Grant
    Filed: November 25, 2014
    Date of Patent: November 15, 2016
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Rahul Sharangpani, Raghuveer S. Makala, Sateesh Koka, George Matamis
  • Patent number: 9484357
    Abstract: A plurality of blocking dielectric portions can be formed between a memory stack structure and an alternating stack of first material layers and second material layers by selective deposition of a dielectric material layer. The plurality of blocking dielectric portions can be formed after removal of the second material layers selective to the first material layers by depositing a dielectric material on surfaces of the memory stack structure while avoiding deposition on surfaces of the first material layers. A deposition inhibitor material layer or a deposition promoter material layer can be optionally employed. Alternatively, the plurality of blocking dielectric portions can be formed on surfaces of the second material layers while avoiding deposition on surfaces of the first material layers after formation of the memory opening and prior to formation of the memory stack structure. The plurality of blocking dielectric portions are vertically spaced annular structures.
    Type: Grant
    Filed: December 16, 2014
    Date of Patent: November 1, 2016
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Raghuveer S. Makala, Rahul Sharangpani, Senaka Krishna Kanakamedala, Xiaofeng Liang, George Matamis, Sateesh Koka, Johann Alsmeier
  • Patent number: 9478558
    Abstract: A first blocking dielectric layer is formed in a memory opening through a stack of an alternating plurality of material layers and insulator layers. A spacer with a bottom opening is formed over the first blocking dielectric layer by deposition of a conformal material layer and an anisotropic etch. A horizontal portion of the first blocking dielectric layer at a bottom of the memory opening can be etched by an isotropic etch process that minimizes overetch into the substrate. An optional additional blocking dielectric layer, at least one charge storage element, a tunneling dielectric, and a semiconductor channel can be sequentially formed in the memory opening to provide a three-dimensional memory stack.
    Type: Grant
    Filed: January 20, 2015
    Date of Patent: October 25, 2016
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Sateesh Koka, Senaka Kanakamedala, Raghuveer S. Makala, Rahul Sharangpani, Yanli Zhang, Yao-Sheng Lee, George Matamis
  • Publication number: 20160307908
    Abstract: Resistance of a semiconductor channel in three-dimensional memory stack structures can be reduced by forming a metal-semiconductor alloy region between a vertical semiconductor channel and a horizontal semiconductor channel located within a substrate. The metal-semiconductor alloy region can be formed by recessing a portion of the semiconductor material layer in the semiconductor substrate underneath a memory opening after formation of a memory film, selectively depositing a metallic material in the recess region, depositing a vertical semiconductor channel, and reacting the deposited metallic material with an adjacent portion of the semiconductor material layer and the vertical semiconductor channel. A sacrificial dielectric material layer can be formed on the memory film prior to the selective deposition of the metallic material.
    Type: Application
    Filed: April 15, 2015
    Publication date: October 20, 2016
    Inventors: Rahul SHARANGPANI, Raghuveer S. MAKALA, Sateesh KOKA, Tomohiro KUBO, Junichi ARIYOSHI, George MATAMIS
  • Publication number: 20160284730
    Abstract: Methods of making monolithic three-dimensional memory devices include performing a first etch to form a memory opening and a second etch using a different etching process to remove a damaged portion of the semiconductor substrate from the bottom of the memory opening. A single crystal semiconductor material is formed over the substrate in the memory opening using an epitaxial growth process. Additional embodiments include improving the quality of the interface between the semiconductor channel material and the underlying semiconductor layers in the memory opening which may be damaged by the bottom opening etch, including forming single crystal semiconductor channel material by epitaxial growth from the bottom surface of the memory opening and/or oxidizing surfaces exposed to the bottom opening etch and removing the oxidized surfaces prior to forming the channel material. Monolithic three-dimensional memory devices formed by the embodiment methods are also disclosed.
    Type: Application
    Filed: June 10, 2016
    Publication date: September 29, 2016
    Inventors: Sateesh KOKA, Raghuveer S. MAKALA, Yanli ZHANG, Senaka KANAKAMEDALA, Rahul SHARANGPANI, Yao-Sheng LEE, George MATAMIS
  • Patent number: 9449982
    Abstract: A method of making a vertical NAND device includes forming a lower portion of a memory stack over a substrate, forming a lower portion of memory openings in the lower portion of the memory stack, and forming a sacrificial material portion including an encapsulated cavity. The method also includes forming an upper portion of the memory stack over the lower portion of the memory stack and over the sacrificial material, forming an upper portion of the memory openings in the upper portion of the memory stack to expose the sacrificial material in the lower portion of the memory openings, removing the sacrificial material portion to connect the lower portion of the memory openings with a respective upper portion of the memory openings to form continuous memory openings, and forming a semiconductor channel in each continuous memory opening.
    Type: Grant
    Filed: June 24, 2015
    Date of Patent: September 20, 2016
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Zhenyu Lu, Sateesh Koka, James Kai, Raghuveer S. Makala, Yao-Sheng Lee, Jayavel Pachamuthu, Johann Alsmeier, Henry Chien
  • Publication number: 20160225866
    Abstract: A memory film and a semiconductor channel can be formed within each memory opening that extends through a stack including an alternating plurality of insulator layers and sacrificial material layers. After formation of backside recesses through removal of the sacrificial material layers selective to the insulator layers, a metallic barrier material portion can be formed in each backside recess. A molybdenum-containing portion can be formed in each backside recess. Each backside recess can be filled with a molybdenum-containing portion alone, or can be filled with a combination of a molybdenum-containing portion and a metallic material portion including a material other than molybdenum.
    Type: Application
    Filed: June 26, 2015
    Publication date: August 4, 2016
    Inventors: Somesh Peri, Raghuveer S. Makala, Sateesh Koka, Yao-Sheng Lee, Johann Alsmeier, George Matamis
  • Publication number: 20160211272
    Abstract: A first blocking dielectric layer is formed in a memory opening through a stack of an alternating plurality of material layers and insulator layers. A spacer with a bottom opening is formed over the first blocking dielectric layer by deposition of a conformal material layer and an anisotropic etch. A horizontal portion of the first blocking dielectric layer at a bottom of the memory opening can be etched by an isotropic etch process that minimizes overetch into the substrate. An optional additional blocking dielectric layer, at least one charge storage element, a tunneling dielectric, and a semiconductor channel can be sequentially formed in the memory opening to provide a three-dimensional memory stack.
    Type: Application
    Filed: January 20, 2015
    Publication date: July 21, 2016
    Inventors: Sateesh Koka, Senaka Kanakamedala, Raghuveer S. Makala, Rahul Sharangpani, Yanli Zhang, Yao-Sheng Lee, George Matamis
  • Patent number: 9397046
    Abstract: Fluorine-induced formation of voids and electrical shorts can be avoided by forming fluorine-free metal lines. Specifically, control gate electrodes of a three-dimensional memory device can be formed employing fluorine-free deposition processes. Fluorine-free tungsten nitride can be deposited as a metallic barrier liner employing atomic layer deposition. Fluorine-free tungsten nucleation layer can be subsequently deposited. Fluorine-free tungsten fill process can be employed to form the control gate electrodes. The fluorine-free control gate electrodes do not include fluorine therein, and thus, circumvents yield and reliability issues associated with residual fluorine that are present in fluorine-containing metal lines.
    Type: Grant
    Filed: April 29, 2015
    Date of Patent: July 19, 2016
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Rahul Sharangpani, Raghuveer S. Makala, Sateesh Koka, George Matamis
  • Patent number: 9379132
    Abstract: Methods of making monolithic three-dimensional memory devices include performing a first etch to form a memory opening and a second etch using a different etching process to remove a damaged portion of the semiconductor substrate from the bottom of the memory opening. A single crystal semiconductor material is formed over the substrate in the memory opening using an epitaxial growth process. Additional embodiments include improving the quality of the interface between the semiconductor channel material and the underlying semiconductor layers in the memory opening which may be damaged by the bottom opening etch, including forming single crystal semiconductor channel material by epitaxial growth from the bottom surface of the memory opening and/or oxidizing surfaces exposed to the bottom opening etch and removing the oxidized surfaces prior to forming the channel material. Monolithic three-dimensional memory devices formed by the embodiment methods are also disclosed.
    Type: Grant
    Filed: October 24, 2014
    Date of Patent: June 28, 2016
    Assignee: SANDISK TECHNOLOGIES INC.
    Inventors: Sateesh Koka, Raghuveer S. Makala, Yanli Zhang, Senaka Kanakamedala, Rahul Sharangpani, Yao-Sheng Lee, George Matamis
  • Publication number: 20160172366
    Abstract: Blocking dielectric structures and/or thicker barrier metal films for preventing or reducing fluorine diffusion are provided. A blocking dielectric layer can be formed as an outer layer of a memory film in a memory stack structure extending through electrically insulating layers and sacrificial material layers. After formation of backside recesses by removal of the sacrificial material layers, dopants can be introduced into physically exposed portions of the blocking dielectric layer, for example, by plasma treatment or thermal treatment, to form silicon oxynitride regions which can reduce or prevent fluorine diffusion. Alternatively or additionally, a set of metal oxide blocking dielectric material portions can be formed in the backside recesses to retard or prevent fluorine diffusion. To minimize adverse impact on the electrically conductive layers formed in the backside recesses, the blocking dielectric material portions can be laterally recessed from a trench employed to form the backside recesses.
    Type: Application
    Filed: June 26, 2015
    Publication date: June 16, 2016
    Inventors: Sateesh KOKA, Raghuveer S. MAKALA, Somesh PERI, Rahul SHARANGPANI, Yao-Sheng LEE, George MATAMIS, Wei ZHAO
  • Publication number: 20160172370
    Abstract: A plurality of blocking dielectric portions can be formed between a memory stack structure and an alternating stack of first material layers and second material layers by selective deposition of a dielectric material layer. The plurality of blocking dielectric portions can be formed after removal of the second material layers selective to the first material layers by depositing a dielectric material on surfaces of the memory stack structure while avoiding deposition on surfaces of the first material layers. A deposition inhibitor material layer or a deposition promoter material layer can be optionally employed. Alternatively, the plurality of blocking dielectric portions can be formed on surfaces of the second material layers while avoiding deposition on surfaces of the first material layers after formation of the memory opening and prior to formation of the memory stack structure. The plurality of blocking dielectric portions are vertically spaced annular structures.
    Type: Application
    Filed: December 16, 2014
    Publication date: June 16, 2016
    Inventors: Raghuveer S. MAKALA, Rahul SHARANGPANI, Senaka Krishna KANAKAMEDALA, Xiaofeng LIANG, George MATAMIS, Sateesh KOKA, Johann ALSMEIER
  • Publication number: 20160148945
    Abstract: A method of making a monolithic three dimensional NAND string including forming a stack of alternating layers of insulating first material and sacrificial second material different from the first material over a major surface of the substrate, forming a front side opening in the stack, forming at least one charge storage region in the front side opening and forming a tunnel dielectric layer over the at least one charge storage region in front side opening. The method also includes forming a semiconductor channel over the tunnel dielectric layer in the front side opening, forming a back side opening in the stack and selectively removing at least portions of the second material layers to form back side recesses between adjacent first material layers.
    Type: Application
    Filed: November 25, 2014
    Publication date: May 26, 2016
    Inventors: Rahul SHARANGPANI, Raghuveer S. MAKALA, Senaka Krishna KANAKAMEDALA, Sateesh KOKA, Yao-Sheng LEE, George MATAMIS
  • Publication number: 20160149049
    Abstract: A memory film and a semiconductor channel can be formed within each memory opening that extends through a stack including an alternating plurality of insulator layers and sacrificial material layers. After formation of backside recesses through removal of the sacrificial material layers selective to the insulator layers, a ruthenium portion can be formed in each backside recess, and a polycrystalline conductive material portion can be formed on each ruthenium portion. Each ruthenium portion can be employed in lieu of a tungsten seed layer to function as a lower resistivity seed layer that enables subsequent deposition of a polycrystalline conductive material. The resulting electrically conductive lines can have a lower resistivity than conductive lines of comparable dimensions that employ tungsten seed layers.
    Type: Application
    Filed: November 25, 2014
    Publication date: May 26, 2016
    Inventors: Rahul SHARANGPANI, Raghuveer S. MAKALA, Sateesh KOKA, George MATAMIS