Patents by Inventor Yao-Sheng Lee

Yao-Sheng Lee 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: 20160322381
    Abstract: A first stack of alternating layers including first electrically insulating layers and first sacrificial material layers is formed with first stepped surfaces. First memory openings can be formed in a device region outside of the first stepped surfaces, and first support openings can be formed through the first stepped surfaces. The first memory openings and the first support openings can be filled with a sacrificial fill material. A second stack of alternating layers including second electrically insulating layers and second sacrificial material layers can be formed over the first stack. Inter-stack memory openings including the first memory openings can be formed in the device region, and inter-stack support openings including the first support openings can be formed in a steppes surface region. Memory stack structures and support pillar structure are simultaneously formed in the inter-stack memory openings and the inter-stack support openings, respectively.
    Type: Application
    Filed: September 23, 2015
    Publication date: November 3, 2016
    Inventors: Jin Liu, Tong Zhang, Jayavel Pachamuthu, Yao-Sheng Lee, 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
  • Patent number: 9460931
    Abstract: A memory device and a method of fabricating a memory device that includes forming a protrusion over a substrate, an etch stop layer over the protrusion, and a stack of alternating material layers over the etch stop layer. The method further includes etching the stack to the etch stop layer to form a memory opening having a first width dimension proximate to the etch stop layer, etching the etch stop layer to provide a void area between the protrusion and a bottom of the memory opening, where the void area has a second width dimension that is larger than the first width dimension, forming a memory film over a sidewall of the memory opening and within the void area over the top surface of the protrusion, etching the memory film to expose the protrusion, and forming a semiconductor channel in the memory opening that is electrically coupled to the protrusion.
    Type: Grant
    Filed: March 25, 2014
    Date of Patent: October 4, 2016
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Jayavel Pachamuthu, Johann Alsmeier, Raghuveer S. Makala, Yao-Sheng Lee
  • 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
  • Patent number: 9437606
    Abstract: A method of making a semiconductor device including forming a sacrificial feature over a substrate, forming a plurality of etch through regions having an etch through material and an etch stop region having an etch stop material over the sacrificial feature, forming a stack of alternating layers of a first material and a second material over the plurality of the etch through regions and the plurality of the etch stop regions, etching the stack to form a plurality of openings through the stack and through the etch through regions to expose the sacrificial feature, such that the etch through material is etched preferentially compared to the first and the second materials of the stack, removing the sacrificial feature through the plurality of openings and etching the stack to form a slit trench up to or only partially through the etch stop region, such that the first and the second materials of the stack are etched preferentially compared to the etch stop material.
    Type: Grant
    Filed: July 2, 2013
    Date of Patent: September 6, 2016
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Raghuveer S. Makala, Johann Alsmeier, Yao-Sheng Lee, Masanori Terahara, Hirofumi Watatani, Jayavel Pachamuthu
  • Patent number: 9431409
    Abstract: A three dimensional memory device including a substrate and a semiconductor channel. At least one end portion of the semiconductor channel extends substantially perpendicular to a major surface of the substrate. The device also includes at least one charge storage region located adjacent to semiconductor channel and a plurality of control gate electrodes having a strip shape extending substantially parallel to the major surface of the substrate. The plurality of control gate electrodes include at least a first control gate electrode located in a first device level and a second control gate electrode located in a second device level located over the major surface of the substrate and below the first device level. The device also includes an etch stop layer located between the substrate and the plurality of control gate electrodes.
    Type: Grant
    Filed: October 30, 2013
    Date of Patent: August 30, 2016
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Yao-Sheng Lee, Johann Alsmeier
  • 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: 9397107
    Abstract: A method of making a three dimensional NAND string includes providing a stack of alternating first material layers and second material layers over a substrate. The method further includes forming a front side opening in the stack, forming a tunnel dielectric in the front side opening, forming a semiconductor channel in the front side opening over the tunnel dielectric and forming a back side opening in the stack. The method also includes selectively removing the second material layers through the back side opening to form back side recesses between adjacent first material layers, forming a metal charge storage layer in the back side opening and in the back side recesses and forming discrete charge storage regions in the back side recesses by removing the metal charge storage layer from the back side opening and selectively recessing the metal charge storage layer in the back side recesses.
    Type: Grant
    Filed: June 30, 2014
    Date of Patent: July 19, 2016
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Raghuveer S. Makala, Yao-Sheng Lee, Senaka Krishna Kanakamedala, Yanli Zhang, George Matamis, Johann Alsmeier
  • 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
  • Patent number: 9356031
    Abstract: A method of making a monolithic three dimensional NAND string includes forming a stack of alternating first and second material layers over a substrate, etching the stack to form a front side opening, partially removing the second material layers through the front side opening to form front side recesses, forming a first blocking dielectric in the front side recesses, forming charge storage regions over the first blocking dielectric in the front side recesses, forming a tunnel dielectric layer and a semiconductor channel over the charge storage regions in the front side opening, etching the stack to form a back side opening, removing the second material layers through the back side opening to form back side recesses using the first blocking dielectric as an etch stop, forming a second blocking dielectric in the back side recesses, and forming control gates over the second blocking dielectric in the back side recesses.
    Type: Grant
    Filed: August 11, 2014
    Date of Patent: May 31, 2016
    Assignee: SANDISK TECHNOLOGIES INC.
    Inventors: Yao-Sheng Lee, Jayavel Pachamuthu, Raghuveer S. Makala, George Matamis, Johann Alsmeier, Henry Chien
  • 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: 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
  • Patent number: 9305932
    Abstract: A method of making a monolithic three dimensional NAND string includes providing a first stack of alternating first material layers and second material layers over a major surface of a substrate. The first material layers include first silicon oxide layers, the second material layers include second silicon oxide layers, and the first silicon oxide layers have a different etch rate from the second silicon oxide when exposed to the same etching medium. The first stack includes a back side opening, a front side opening, and at least a portion of a floating gate layer, a tunnel dielectric and a semiconductor channel located in the front side opening. The method also includes selectively removing the first material layers through the back side opening to form back side control gate recesses between adjacent second material layers.
    Type: Grant
    Filed: June 30, 2014
    Date of Patent: April 5, 2016
    Assignee: SANDISK TECHNOLOGIES INC.
    Inventors: Senaka Krishna Kanakamedala, Yanli Zhang, Raghuveer S. Makala, Yao-Sheng Lee, Johann Alsmeier, George Matamis
  • Patent number: 9305935
    Abstract: A method of making multi-level contacts. The method includes providing an in-process multilevel device including at least one device region and at least one contact region. The contact region includes a plurality of electrically conductive layers configured in a step pattern. The method also includes forming a conformal etch stop layer over the plurality of electrically conductive layers, forming a first electrically insulating layer over the etch stop layer, forming a conformal sacrificial layer over the first electrically insulating layer and forming a second electrically insulating layer over the sacrificial layer. The method also includes etching a plurality of contact openings through the etch stop layer, the first electrically insulating layer, the sacrificial layer and the second electrically insulating layer in the contact region to the plurality of electrically conductive layers.
    Type: Grant
    Filed: February 25, 2015
    Date of Patent: April 5, 2016
    Assignee: SANDISK TECHNOLOGIES INC.
    Inventors: Yao-Sheng Lee, Zhen Chen, Syo Fukata
  • Publication number: 20160064532
    Abstract: Methods of making a monolithic three dimensional NAND string that include forming a stack of alternating first material layers and second material layers over a substrate, where each of the second material layers includes a layer of a first silicon oxide material between two layers of a second silicon oxide material different from the first silicon oxide material, etching the stack to form a front side opening in the stack, forming a memory film over a sidewall of the front side opening, and forming a semiconductor channel in the front side opening such that at least a portion of the memory film is located between the semiconductor channel and the sidewall of the front side opening, where at least one of an air gap or a material which has a dielectric constant below 3.9 is formed between the respective two layers of second silicon oxide material.
    Type: Application
    Filed: August 26, 2014
    Publication date: March 3, 2016
    Inventors: Raghuveer S. MAKALA, Yanli ZHANG, Rahul SHARANGPANI, Yao-Sheng LEE, Senaka Krishna KANAKAMEDALA, George MATAMIS, Johann ALSMEIER
  • Publication number: 20160049421
    Abstract: A monolithic three dimensional NAND string includes a plurality of control gate electrodes extending substantially parallel to a major surface of a substrate, a memory opening extending substantially perpendicular to the major surface of the substrate and filled with a memory opening material including a memory film, and a dummy opening extending substantially perpendicular to the major surface of the substrate and filled with a dummy channel material which is different from the memory opening material. The dummy channel material has a higher Young's modulus than the memory opening material to offset warpage of the substrate due to the one of compressive and tensile stress imposed by the plurality of control gate electrodes on the substrate.
    Type: Application
    Filed: August 18, 2014
    Publication date: February 18, 2016
    Inventors: Yanli ZHANG, Raghuveer S. MAKALA, Johann ALSMEIER, Yao-Sheng LEE, Tiger XU
  • Publication number: 20160043093
    Abstract: A method of making a monolithic three dimensional NAND string includes forming a stack of alternating first and second material layers over a substrate, etching the stack to form a front side opening, partially removing the second material layers through the front side opening to form front side recesses, forming a first blocking dielectric in the front side recesses, forming charge storage regions over the first blocking dielectric in the front side recesses, forming a tunnel dielectric layer and a semiconductor channel over the charge storage regions in the front side opening, etching the stack to form a back side opening, removing the second material layers through the back side opening to form back side recesses using the first blocking dielectric as an etch stop, forming a second blocking dielectric in the back side recesses, and forming control gates over the second blocking dielectric in the back side recesses.
    Type: Application
    Filed: August 11, 2014
    Publication date: February 11, 2016
    Inventors: Yao-Sheng Lee, Jayavel Pachamuthu, Raghuveer S. Makala, George Matamis, Johann Alsmeier, Henry Chien