Patents by Inventor Rahul Sharangpani

Rahul Sharangpani 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: 10290648
    Abstract: An alternating stack of insulating layers and spacer material layers located over a substrate. The spacer material layers are formed as, or are subsequently replaced with, electrically conductive layers. Memory stack structures are formed through the alternating stack. After formation of a backside trench, electrically-conductive-layer-level recessed cavities are formed by laterally recessing the electrically conductive layers around the backside trench. Electrically conductive rails are formed on remaining portions of the electrically conductive layers by selective deposition of a conductive material. Insulating-layer-level recessed cavities are formed by laterally recessing the insulating layers around the backside trench. A continuous insulating material layer can be formed in the insulating-layer-level recessed cavities with air gap rails cavities to reduce capacitive coupling among the electrically conducive rails.
    Type: Grant
    Filed: December 7, 2017
    Date of Patent: May 14, 2019
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Fei Zhou, Raghuveer S. Makala, Rahul Sharangpani, Adarsh Rajashekhar
  • Patent number: 10290652
    Abstract: A method of forming a three-dimensional memory device includes providing an alternating stack of insulating layers and sacrificial material layers located between a first trench and a second trench, forming memory stack structures extending vertically through the alternating stack, wherein each of the memory stack structures contains a memory film and a vertical semiconductor channel, removing the sacrificial material layers selective to the insulating layers through the first and the second trenches to form backside recesses having a first proximal region adjacent to the first trench, a second proximal region adjacent to the second trench and a distal region located between the first and the second proximal regions, and forming fluorine-free tungsten layers in the respective backside recesses such that each fluorine-free tungsten layer has a greater thickness in the distal region than in the first and the second proximal regions.
    Type: Grant
    Filed: May 30, 2018
    Date of Patent: May 14, 2019
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Rahul Sharangpani, Raghuveer S. Makala, Fei Zhou, Adarsh Rajashekhar
  • Publication number: 20190139973
    Abstract: A memory opening is formed through an alternating stack of insulating layers and sacrificial material layers located over a substrate. Annular recesses are formed around the memory opening by laterally recessing the sacrificial material layers with respect to the insulating layers. Annular metal portions are formed over recessed sidewalls of the sacrificial material layers within each of the annular recesses by a selective deposition process. Annular backside blocking dielectrics are formed selectively on inner sidewalls of the annular metal portions employing a layer of a self-assembly material that covers surfaces of the insulating layers and inhibits deposition of a dielectric material thereupon. A memory stack structure is formed in the memory opening, and the sacrificial material layers are replaced with electrically conductive layers. The annular backside blocking dielectrics provide electrical isolation for the annular metal portions, which function as control gate electrodes.
    Type: Application
    Filed: November 6, 2017
    Publication date: May 9, 2019
    Inventors: Fei Zhou, Raghuveer S. Makala, Rahul Sharangpani, Adarsh Rajashekhar
  • Patent number: 10283513
    Abstract: A memory opening is formed through an alternating stack of insulating layers and sacrificial material layers located over a substrate. Annular recesses are formed around the memory opening by laterally recessing the sacrificial material layers with respect to the insulating layers. Annular metal portions are formed over recessed sidewalls of the sacrificial material layers within each of the annular recesses by a selective deposition process. Annular backside blocking dielectrics are formed selectively on inner sidewalls of the annular metal portions employing a layer of a self-assembly material that covers surfaces of the insulating layers and inhibits deposition of a dielectric material thereupon. A memory stack structure is formed in the memory opening, and the sacrificial material layers are replaced with electrically conductive layers. The annular backside blocking dielectrics provide electrical isolation for the annular metal portions, which function as control gate electrodes.
    Type: Grant
    Filed: November 6, 2017
    Date of Patent: May 7, 2019
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Fei Zhou, Raghuveer S. Makala, Rahul Sharangpani, Adarsh Rajashekhar
  • Patent number: 10276583
    Abstract: Word lines for a three-dimensional memory device can be formed by forming a stack of alternating layers comprising insulating layers and sacrificial material layers and memory stack structures vertically extending therethrough. Backside recesses are formed by removing the sacrificial material layers through a backside via trench. A metal silicide layer and metal portion are formed in the backside recesses to form the word lines including a metal portion, a metal silicide layer, and optionally, a silicon-containing layer.
    Type: Grant
    Filed: October 11, 2017
    Date of Patent: April 30, 2019
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Rahul Sharangpani, Fumitaka Amano, Raghuveer S. Makala, Adarsh Rajashekhar, Fei Zhou
  • Publication number: 20180366482
    Abstract: A three-dimensional memory device can be formed by first forming an alternating stack of insulating layers and stack level spacer material layers over a substrate. The stack level spacer material layers can be formed as, or are subsequently replaced with, stack level electrically conductive layers. A bottommost insulating spacer layer is formed with recesses that form grooves that are laterally spaced apart. Drain select level electrically conductive layers are formed over protruding portions and within the grooves of the bottommost insulating spacer layer by anisotropic deposition and isotropic etch back of a conductive material. Additional insulating spacer layers may be formed by anisotropic deposition of an insulating material. Additional drain select level electrically conductive layers can be formed by anisotropic deposition and isotropic etch back of additional conductive material.
    Type: Application
    Filed: June 20, 2017
    Publication date: December 20, 2018
    Inventors: Fei Zhou, Rahul Sharangpani, Yanli Zhang, Raghuveer S. Makala, Senaka Krishna Kanakamedala
  • Patent number: 10128261
    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 cobalt portion can be formed in each backside recess. Each backside recess can be filled with a cobalt portion alone, or can be filled with a combination of a cobalt portion and a metallic material portion including a material other than cobalt.
    Type: Grant
    Filed: February 4, 2015
    Date of Patent: November 13, 2018
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Raghuveer S. Makala, Rahul Sharangpani, Sateesh Koka, Genta Mizuno, Naoki Takeguchi, Senaka Krishna Kanakamedala, George Matamis, Yao-Sheng Lee, Johann Alsmeier
  • Patent number: 10050054
    Abstract: A layer stack including an alternating stack of insulating layers and sacrificial material layers is formed over a substrate. After formation of memory stack structures, backside trenches are formed through the layer stack. The sacrificial material layers are replaced with electrically conductive layers. Drain select level dielectric isolation structures are formed through drain select level of the stack after formation of the electrically conductive layers. The drain select level dielectric isolation structures laterally separate portions of conductive layers that are employed as drain select level gate electrodes for the memory stack structures.
    Type: Grant
    Filed: October 5, 2016
    Date of Patent: August 14, 2018
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Yanli Zhang, Johann Alsmeier, Raghuveer S. Makala, Senaka Kanakamedala, Rahul Sharangpani, James Kai
  • Patent number: 9984963
    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: Grant
    Filed: July 29, 2016
    Date of Patent: May 29, 2018
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Somesh Peri, Rahul Sharangpani, Raghuveer S. Makala, Senaka Kanakamedala, Keerti Shukla
  • Patent number: 9960180
    Abstract: Memory openings can be formed through an alternating stack of insulating layers and sacrificial material layers. Memory stack structures including charge storage elements can be formed in the memory openings. Inter-level charge leakage in a three-dimensional memory device including a charge trapping layer can be minimized by employing a thin continuous charge trapping material layer within each memory opening. After removal of the sacrificial material layers and formation of backside recesses, discrete charge trapping material portions can be formed by selective growth of a charge trapping material from physically exposed surfaces of each thin continuous charge trapping material layer. The discrete charge trapping material portions can function as primary charge storage regions, and inter-level charge leakage can be minimized by the small thickness of the thin continuous charge trapping material layer.
    Type: Grant
    Filed: March 27, 2017
    Date of Patent: May 1, 2018
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Fei Zhou, Raghuveer Makala, Rahul Sharangpani, Keerti Shukla, Yanli Zhang, Peng Zhang
  • Publication number: 20180097009
    Abstract: A layer stack including an alternating stack of insulating layers and sacrificial material layers is formed over a substrate. After formation of memory stack structures, backside trenches are formed through the layer stack. The sacrificial material layers are replaced with electrically conductive layers. Drain select level dielectric isolation structures are formed through drain select level of the stack after formation of the electrically conductive layers. The drain select level dielectric isolation structures laterally separate portions of conductive layers that are employed as drain select level gate electrodes for the memory stack structures.
    Type: Application
    Filed: October 5, 2016
    Publication date: April 5, 2018
    Inventors: Yanli ZHANG, Johann ALSMEIER, Raghuveer S. MAKALA, Senaka KANAKAMEDALA, Rahul SHARANGPANI, James KAI
  • Publication number: 20180090373
    Abstract: A method of forming a memory device includes forming an alternating stack of insulating layers and sacrificial material layers over a substrate forming memory stack structures through the alternating stack, forming a first backside trench and a second backside trench through the alternating stack, forming backside recesses by removing the sacrificial material layers, depositing a backside blocking dielectric layer after formation of the backside recesses, forming a liner that a lesser lateral extent than a lateral distance between the first backside trench and the second backside trench; and selectively growing a metal from surfaces of the liners while either not growing or growing at a lower rate the metal from surfaces of the backside recesses that are not covered by the liners.
    Type: Application
    Filed: December 4, 2017
    Publication date: March 29, 2018
    Inventors: Rahul Sharangpani, Raghuveer S. Makala, Fei Zhou, Adarsh Rajashekhar, Senaka Krishna Kanakamedala, Fumitaka Amano, Genta Mizuno
  • 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
  • Publication number: 20180033646
    Abstract: Word lines for a three-dimensional memory device can be formed by forming a stack of alternating layers comprising insulating layers and sacrificial material layers and memory stack structures vertically extending therethrough. Backside recesses are formed by removing the sacrificial material layers through a backside via trench. A metal silicide layer and metal portion are formed in the backside recesses to form the word lines including a metal portion, a metal silicide layer, and optionally, a silicon-containing layer.
    Type: Application
    Filed: October 11, 2017
    Publication date: February 1, 2018
    Inventors: Rahul SHARANGPANI, Fumitaka AMANO, Raghuveer S. MAKALA, Adarsh RAJASHEKHAR, Fei ZHOU
  • Patent number: 9875929
    Abstract: A memory opening is formed through an alternating stack of sacrificial material layers and electrically conductive layers located over a substrate. Discrete annular dielectric metal oxide structures are formed on sidewalls of the electrically conductive layers around the memory opening. After forming memory stack structures including the annular dielectric metal oxide structures in the memory opening, lateral recesses are formed by removing the sacrificial material layers selective to the electrically conductive layers. Sacrificial material layers in the memory stack structure are etched at levels of the lateral recesses to form discrete annular structures at each level of the electrically conductive layers, each of which includes, from inside to outside, a respective annular charge storage structure, and a respective blocking dielectric comprising an annular dielectric metal oxide structure.
    Type: Grant
    Filed: January 23, 2017
    Date of Patent: January 23, 2018
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Keerti Shukla, Raghuveer S. Makala, Rahul Sharangpani, Fei Zhou
  • Publication number: 20170373197
    Abstract: Memory stack structures are formed through an alternating stack of insulating layers and sacrificial material layers. Backside recesses are formed by removal of the sacrificial material layers selective to the insulating layers and the memory stack structures. An electrically conductive, amorphous barrier layer can be formed prior to formation of a metal fill material layer to provide a diffusion barrier that reduces fluorine diffusion between the metal fill material layer and memory films of memory stack structures. The electrically conductive, amorphous barrier layer can be an oxygen-containing titanium compound or a ternary transition metal nitride.
    Type: Application
    Filed: October 12, 2016
    Publication date: December 28, 2017
    Inventors: Rahul Sharangpani, Raghuveer S. Makala, Keerti Shukla, Fei Zhou, Somesh Peri
  • Publication number: 20170373079
    Abstract: Memory stack structures are formed through an alternating stack of insulating layers and sacrificial material layers. Backside recesses are formed by removal of the sacrificial material layers selective to the insulating layers and the memory stack structures. A barrier layer stack including a crystalline electrically conductive barrier layer and an amorphous barrier layer is formed in the backside recesses prior to formation of a metal fill material layer.
    Type: Application
    Filed: April 10, 2017
    Publication date: December 28, 2017
    Inventors: Rahul SHARANGPANI, Fumitaka AMANO, Raghuveer S. MAKALA, Fei ZHOU, Keerti SHUKLA
  • Patent number: 9842907
    Abstract: An alternating stack of insulating layers and sacrificial material layers can be formed over a substrate. Memory stack structures and a backside trench are formed through the alternating stack. Backside recesses are formed by removing the sacrificial material layers from the backside trench selective to the insulating layers. A cobalt-semiconductor alloy portion is formed in each backside recess by reacting cobalt and a semiconductor material. Conductive material in the backside trench can be removed by an etch to electrically isolate cobalt-containing alloy portions located in different backside recesses. Electrically conductive layers including a respective cobalt-semiconductor alloy portion can be employed as word lines of a three-dimensional memory device.
    Type: Grant
    Filed: September 29, 2015
    Date of Patent: December 12, 2017
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Raghuveer S. Makala, Sateesh Koka, Zhenyu Lu, Somesh Peri, Rahul Sharangpani