Patents by Inventor Senaka Kanakamedala

Senaka Kanakamedala 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: 9893081
    Abstract: After formation of a memory opening through an alternating stack of insulating layers and sacrificial material layers, a blocking dielectric having a greater thickness at levels of the insulating layers than at levels of the sacrificial material layers is formed around, or within, the memory opening. A memory stack structure is formed within the memory opening. Backside recesses are formed by removing the sacrificial material layers and surface portions of the blocking dielectric to form backside recesses including vertically expanded end portions. Electrically conductive layers are formed within the backside recesses. Each of the electrically conductive layers is a control gate electrode which includes a uniform thickness portion and a ridged end portion having a greater vertical extent than the uniform thickness region. The ridged end portion laterally surrounds the memory stack structure and provides a longer gate length for the control gate electrodes for the memory stack structure.
    Type: Grant
    Filed: August 8, 2016
    Date of Patent: February 13, 2018
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Senaka Kanakamedala, Rahul Sharangpani, Raghuveer S. Makala, Somesh Peri, Yao-Sheng Lee
  • Publication number: 20180040627
    Abstract: After formation of a memory opening through an alternating stack of insulating layers and sacrificial material layers, a blocking dielectric having a greater thickness at levels of the insulating layers than at levels of the sacrificial material layers is formed around, or within, the memory opening. A memory stack structure is formed within the memory opening. Backside recesses are formed by removing the sacrificial material layers and surface portions of the blocking dielectric to form backside recesses including vertically expanded end portions. Electrically conductive layers are formed within the backside recesses. Each of the electrically conductive layers is a control gate electrode which includes a uniform thickness portion and a ridged end portion having a greater vertical extent than the uniform thickness region. The ridged end portion laterally surrounds the memory stack structure and provides a longer gate length for the control gate electrodes for the memory stack structure.
    Type: Application
    Filed: August 8, 2016
    Publication date: February 8, 2018
    Inventors: Senaka Kanakamedala, Rahul Sharangpani, Raghuveer S. Makala, Somesh Peri, Yao-Sheng Lee
  • Publication number: 20180040623
    Abstract: Azimuthally-split metal-semiconductor alloy floating gate electrodes can be formed by providing an alternating stack of insulating layers and spacer material layers, forming a dielectric separator structure extending through the alternating stack, and forming memory openings that divides the dielectric separator structure into a plurality of dielectric separator structures. The spacer material layers are formed as, or are replaced with, electrically conductive layers, which are laterally recessed selective to the insulating layers and the plurality of dielectric separator structures to form a pair of lateral cavities at each level of the electrically conductive layers in each memory opening. After formation of a blocking dielectric layer, a pair of physically disjoined metal-semiconductor alloy portions are formed in each pair of lateral cavities as floating gate electrodes. A tunneling dielectric layer and a semiconductor channel layer is subsequently formed in each memory opening.
    Type: Application
    Filed: August 3, 2016
    Publication date: February 8, 2018
    Inventors: Senaka Kanakamedala, Raghuveer S. Makala, Rahul Sharangpani, Somesh Peri, Yao-Sheng Lee
  • Patent number: 9824966
    Abstract: A sacrificial film and an alternating stack of insulating layers and sacrificial material layers are sequentially formed over a substrate. A memory stack structure including a memory film and a vertical semiconductor channel is formed through the alternating stack and the sacrificial film on the substrate. A source level cavity is formed by introducing an etchant or a reactant through a backside trench and removing the sacrificial film. After removal of an annular portion of the memory film, a portion of the vertical semiconductor channel is converted into an annular source region by introducing electrical dopants into the channel. A source contact layer is formed in the source level cavity and directly on the annular source region. The sacrificial material layers are replaced with electrically conductive layers. The annular source region and the source contact layer can provide low source contact resistance in a three-dimensional NAND memory device.
    Type: Grant
    Filed: August 12, 2016
    Date of Patent: November 21, 2017
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Senaka Kanakamedala, Raghuveer S. Makala, Yanli Zhang, Rahul Sharangpani, James Kai, Yao-Sheng Lee
  • Patent number: 9812463
    Abstract: A memory opening can be formed through an alternating stack of insulating layers and sacrificial material layers provided over a substrate. Annular etch stop material portions are provided at each level of the sacrificial material layers around the memory opening. The annular etch stop material portions can be formed by conversion of surface portions of the sacrificial material layers into dielectric material portion, or by recessing the sacrificial material layers around the memory opening and filling indentations around the memory opening. After formation of a memory stack structure, the sacrificial material layers are removed from the backside. The annular etch stop material portions are at least partially converted to form charge trapping material portions. Vertical isolation of the charge trapping material portions among one another around the memory stack structure minimizes leakage between the charge trapping material portions located at different word line levels.
    Type: Grant
    Filed: August 29, 2016
    Date of Patent: November 7, 2017
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Rahul Sharangpani, Raghuveer S. Makala, Senaka Kanakamedala, Fei Zhou, Somesh Peri, Masanori Tsutsumi, Keerti Shukla, Yusuke Ikawa, Kiyohiko Sakakibara, Eisuke Takii
  • Patent number: 9806090
    Abstract: A method of making a monolithic three dimensional NAND string which contains a semiconductor channel and a plurality of control gate electrodes, includes selectively forming a plurality of discrete charge storage regions using atomic layer deposition. The plurality of discrete charge storage regions includes at least one of a metal or an electrically conductive metal oxide.
    Type: Grant
    Filed: June 9, 2016
    Date of Patent: October 31, 2017
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Rahul Sharangpani, Raghuveer S. Makala, Thomas Jongwan Kwon, Senaka Kanakamedala, George Matamis
  • Publication number: 20170278859
    Abstract: A memory opening can be formed through an alternating stack of insulating layers and sacrificial material layers provided over a substrate. Annular etch stop material portions are provided at each level of the sacrificial material layers around the memory opening. The annular etch stop material portions can be formed by conversion of surface portions of the sacrificial material layers into dielectric material portion, or by recessing the sacrificial material layers around the memory opening and filling indentations around the memory opening. After formation of a memory stack structure, the sacrificial material layers are removed from the backside. The annular etch stop material portions are at least partially converted to form charge trapping material portions. Vertical isolation of the charge trapping material portions among one another around the memory stack structure minimizes leakage between the charge trapping material portions located at different word line levels.
    Type: Application
    Filed: August 29, 2016
    Publication date: September 28, 2017
    Inventors: Rahul SHARANGPANI, Raghuveer S. MAKALA, Senaka KANAKAMEDALA, Fei ZHOU, Somesh PERI, Masanori TSUTSUMI, Keerti SHUKLA, Yusuke IKAWA, Kiyohiko SAKAKIBARA, Eisuke TAKII
  • Patent number: 9659955
    Abstract: A method of forming a device includes forming an alternating stack of insulating layers and sacrificial material layers over a substrate, forming a memory opening extending through the alternating stack, and forming an aluminum oxide layer on sidewall surfaces of the sacrificial material layers and on sidewall surfaces of the insulating layers around the memory opening. First aluminum oxide portions of the aluminum oxide layer are located on sidewall surfaces of the sacrificial material layers, and second aluminum oxide portions of the aluminum oxide layer are located on sidewalls of the insulating layers. The method also includes removing the second aluminum oxide portions at a greater etch rate than the first aluminum oxide portions employing a selective etch process, such that all or a predominant portion of each first aluminum oxide portion remains after removal of the second aluminum oxide portions.
    Type: Grant
    Filed: October 28, 2015
    Date of Patent: May 23, 2017
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Rahul Sharangpani, Sateesh Koka, Raghuveer S. Makala, Somesh Peri, Senaka Kanakamedala
  • Patent number: 9646990
    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: June 10, 2016
    Date of Patent: May 9, 2017
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Sateesh Koka, Raghuveer S. Makala, Yanli Zhang, Senaka Kanakamedala, Rahul Sharangpani, Yao-Sheng Lee, George Matamis
  • Publication number: 20170125436
    Abstract: A method of forming a device includes forming an alternating stack of insulating layers and sacrificial material layers over a substrate, forming a memory opening extending through the alternating stack, and forming an aluminum oxide layer on sidewall surfaces of the sacrificial material layers and on sidewall surfaces of the insulating layers around the memory opening. First aluminum oxide portions of the aluminum oxide layer are located on sidewall surfaces of the sacrificial material layers, and second aluminum oxide portions of the aluminum oxide layer are located on sidewalls of the insulating layers. The method also includes removing the second aluminum oxide portions at a greater etch rate than the first aluminum oxide portions employing a selective etch process, such that all or a predominant portion of each first aluminum oxide portion remains after removal of the second aluminum oxide portions.
    Type: Application
    Filed: October 28, 2015
    Publication date: May 4, 2017
    Inventors: Rahul SHARANGPANI, Sateesh KOKA, Raghuveer S. MAKALA, Somesh PERI, Senaka KANAKAMEDALA
  • Patent number: 9627399
    Abstract: An alternating stack of insulating layers and sacrificial material layers is formed on a substrate. Separator insulator structures can be optionally formed through the alternating stack. Memory opening are formed through the alternating stack, and the sacrificial material layers are removed selective to the insulating layers. Electrically conductive layers are formed in the lateral recesses by deposition of at least one conductive material. Metal-semiconductor alloy regions are appended to the electrically conductive layers by depositing at least a semiconductor material and inducing reaction of the semiconductor material with the material of the electrically conductive layers and/or a sacrificial metal layer. Memory stack structures can be formed in the memory openings and directly on the metal-semiconductor alloy regions of the electrically conductive layers.
    Type: Grant
    Filed: July 24, 2015
    Date of Patent: April 18, 2017
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Senaka Kanakamedala, Raghuveer S. Makala, Yanli Zhang, Yao-Sheng Lee, George Matamis
  • Publication number: 20170025431
    Abstract: An alternating stack of insulating layers and sacrificial material layers is formed on a substrate. Separator insulator structures can be optionally formed through the alternating stack. Memory opening are formed through the alternating stack, and the sacrificial material layers are removed selective to the insulating layers. Electrically conductive layers are formed in the lateral recesses by deposition of at least one conductive material. Metal-semiconductor alloy regions are appended to the electrically conductive layers by depositing at least a semiconductor material and inducing reaction of the semiconductor material with the material of the electrically conductive layers and/or a sacrificial metal layer. Memory stack structures can be formed in the memory openings and directly on the metal-semiconductor alloy regions of the electrically conductive layers.
    Type: Application
    Filed: July 24, 2015
    Publication date: January 26, 2017
    Inventors: Senaka KANAKAMEDALA, Raghuveer S. MAKALA, Yanli ZHANG, Yao-Sheng LEE, George MATAMIS
  • Publication number: 20160351497
    Abstract: A memory stack structure including a memory film and a vertical 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 backside blocking dielectric layer is formed in the backside recesses and sidewalls of the memory stack structures. A metallic barrier material portion can be formed in each backside recess. A cobalt metal portion can be formed in each backside recess. Each backside recess can be filled with a portion of a backside blocking dielectric layer, a metallic barrier material portion, a cobalt metal portion, and a metallic material portion including a material other than cobalt.
    Type: Application
    Filed: July 29, 2016
    Publication date: December 1, 2016
    Inventors: Somesh Peri, Rahul Sharangpani, Raghuveer S. Makala, Senaka Kanakamedala, Keerti Shukla
  • 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: 20160293617
    Abstract: A method of making a monolithic three dimensional NAND string which contains a semiconductor channel and a plurality of control gate electrodes, includes selectively forming a plurality of discrete charge storage regions using atomic layer deposition. The plurality of discrete charge storage regions includes at least one of a metal or an electrically conductive metal oxide.
    Type: Application
    Filed: June 9, 2016
    Publication date: October 6, 2016
    Inventors: Rahul SHARANGPANI, Raghuveer S. MAKALA, Thomas Jongwan KWON, Senaka KANAKAMEDALA, 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
  • 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: 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
  • Patent number: 9379124
    Abstract: A method of making a monolithic three dimensional NAND string which contains a semiconductor channel and a plurality of control gate electrodes, includes selectively forming a plurality of discrete charge storage regions using atomic layer deposition. The plurality of discrete charge storage regions includes at least one of a metal or an electrically conductive metal oxide.
    Type: Grant
    Filed: June 25, 2014
    Date of Patent: June 28, 2016
    Assignee: SANDISK TECHNOLOGIES INC.
    Inventors: Rahul Sharangpani, Raghuveer S. Makala, Thomas Jongwan Kwon, Senaka Kanakamedala, George Matamis
  • Publication number: 20160118397
    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: October 24, 2014
    Publication date: April 28, 2016
    Inventors: Sateesh KOKA, Raghuveer S. MAKALA, Yanli ZHANG, Senaka KANAKAMEDALA, Rahul SHARANGPANI, Yao-Sheng LEE, George MATAMIS