Patents by Inventor Jayavel Pachamuthu

Jayavel Pachamuthu 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: 9230979
    Abstract: A high dielectric constant (high-k) dielectric material layer having a dielectric constant greater than 7.9 is formed a substrate. A stack of alternating layers comprising first material layers and second material layers is formed over the high-k dielectric material layer. A memory opening is formed through the stack employing a top surface of the high-k dielectric material layer as an etchstop layer, thereby minimizing an overetch. A memory film and a semiconductor channel are subsequently formed. During formation of a backside contact trench, the high-k dielectric material layer can be employed as an etch stop layer. Thus, the high-k dielectric material layer can be employed as a common etch stop layer for formation of the memory opening and the backside contact trench.
    Type: Grant
    Filed: October 31, 2014
    Date of Patent: January 5, 2016
    Assignee: SANDISK TECHNOLOGIES INC.
    Inventors: Jayavel Pachamuthu, Johann Alsmeier
  • Publication number: 20150380418
    Abstract: A NAND memory cell region of a NAND device includes a conductive source line that extends substantially parallel to a major surface of a substrate, a first semiconductor channel that extends substantially perpendicular to a major surface of the substrate, and a second semiconductor channel that extends substantially perpendicular to the major surface of the substrate. At least one of a bottom portion and a side portion of the first semiconductor channel contacts the conductive source line and at least one of a bottom portion and a side portion of the second semiconductor channel contacts the conductive source line.
    Type: Application
    Filed: June 27, 2014
    Publication date: December 31, 2015
    Inventors: Yanli Zhang, Go Shoji, Johann Alsmeier, Jayavel Pachamuthu, Yingda Dong, Jiahui Yuan
  • Patent number: 9224502
    Abstract: Techniques are presented for the determination and handling of defects in non-volatile arrays, particularly those having a 3D or BiCS type of arrangement where NAND strings run in a vertical direction relative to the substrate. In such an arrangement, the NAND strings are formed along memory holes and connected to global bit lines, and are separated into blocks or sub-blocks by vertical local interconnects, such as for source lines, and connected to a corresponding global line. To determine defects, an AC stress can be applied between the interconnects and the bit lines/NAND strings, after which a defect determination operation can be performed. This technique can also be implemented at the system level by having the controller instruct the memory to perform it as part of an adaptive defect determination operation.
    Type: Grant
    Filed: January 14, 2015
    Date of Patent: December 29, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Jagdish Sabde, Sagar Magia, Jayavel Pachamuthu, Deepak Raghu
  • Publication number: 20150364488
    Abstract: A memory device and a method of making a memory device that includes a stack of alternating layers of a first material and a second material different from the first material over a substrate, where the layers of the second material form a plurality of conductive control gate electrodes. A plurality of NAND memory strings extend through the stack, where each NAND memory string includes a semiconductor channel which contains at least a first portion which extends substantially perpendicular to a major surface of the substrate and at least one memory film located between the semiconductor channel and the plurality of conductive control gate electrodes. A source line including a metal silicide material extends through the stack.
    Type: Application
    Filed: June 9, 2015
    Publication date: December 17, 2015
    Inventors: Jayavel PACHAMUTHU, Yingda DONG, Johann ALSMEIER
  • Patent number: 9209031
    Abstract: A fabrication process is provided for a 3D stacked non-volatile memory device which provides a source contact to memory holes at a bottom of a stack. The stack includes alternating control gate layers and dielectric layers on a substrate, and memory holes are etched through the stack. The process avoids the need to etch through films at the bottom of the memory hole. Instead, a path is formed from the bottom of the memory hole to the top of the stack. The path includes a horizontal portion using a voided trench in a substrate dielectric, and a passageway etched in the stack. The memory films, a channel material and a dielectric material are deposited throughout the interior surfaces of the void and the memory holes concurrently. The path is filled with metal to form a continuous, low resistance conductive path.
    Type: Grant
    Filed: March 7, 2014
    Date of Patent: December 8, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Matthias Baenninger, Johann Alsmeier, Akira Matsudaira, Jayavel Pachamuthu
  • Patent number: 9202593
    Abstract: Techniques for determining broken word lines in non-volatile memory arrays are presented, which are particularly applicable to 3D NAND memory, such as that of the BiCS type. One set of techniques uses test program operation that alternates a standard staircase waveform with an elongated verify operation. This allows for a more accurate verify of under-programmed broken word lines relative to the standard verify operation. Another set of techniques looks at the ramp rate along the interconnect between the word line decoding circuitry and the main part of the word line. These techniques can also be used for determining defective select gate lines of an array with a NAND type structure.
    Type: Grant
    Filed: September 2, 2014
    Date of Patent: December 1, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Sagar Magia, Jagdish Sabde, Tien-Chien Kuo, Jayavel Pachamuthu
  • Patent number: 9177966
    Abstract: A monolithic three dimensional NAND string device includes a semiconductor channel, at least one end portion of the semiconductor channel extending substantially perpendicular to a major surface of a substrate, a plurality of control gate electrodes extending substantially parallel to the major surface of the substrate in different device levels, a blocking dielectric located in contact with the plurality of control gate electrodes, at least one charge storage region located in contact with the blocking dielectric, and a tunnel dielectric located between the at least one charge storage region and the semiconductor channel. The semiconductor channel is a hollow body surrounding a middle region and at least one of an air gap or a low-k insulating material having a dielectric constant of less than 3.9 is located in the middle region.
    Type: Grant
    Filed: July 8, 2014
    Date of Patent: November 3, 2015
    Assignee: SANDISK TECHNOLOGIES INC.
    Inventors: Peter Rabkin, Wei Zhao, Yanli Zhang, Jayavel Pachamuthu
  • Publication number: 20150294978
    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: Application
    Filed: June 24, 2015
    Publication date: October 15, 2015
    Inventors: Zhenyu LU, Sateesh KOKA, James KAI, Raghuveer S. MAKALA, Yao-Sheng LEE, Jayavel PACHAMUTHU, Johann ALSMEIER, Henry CHIEN
  • Publication number: 20150255481
    Abstract: A fabrication process is provided for a 3D stacked non-volatile memory device which provides a source contact to memory holes at a bottom of a stack. The stack includes alternating control gate layers and dielectric layers on a substrate, and memory holes are etched through the stack. The process avoids the need to etch through films at the bottom of the memory hole. Instead, a path is formed from the bottom of the memory hole to the top of the stack. The path includes a horizontal portion using a voided trench in a substrate dielectric, and a passageway etched in the stack. The memory films, a channel material and a dielectric material are deposited throughout the interior surfaces of the void and the memory holes concurrently. The path is filled with metal to form a continuous, low resistance conductive path.
    Type: Application
    Filed: March 7, 2014
    Publication date: September 10, 2015
    Applicant: SanDisk Technologies Inc.
    Inventors: Matthias Baenninger, Johann Alsmeier, Akira Matsudaira, Jayavel Pachamuthu
  • Patent number: 9123714
    Abstract: Air gaps are provided to reduce interference and resistance between metal bit lines in non-volatile memory structures. Metal vias can be formed that are electrically coupled with the drain region of an underlying device and extend vertically with respect to the substrate surface to provide contacts for bit lines that are elongated in a column direction above. The metal vias can be separated by a dielectric fill material. Layer stack columns extend in a column direction over the dielectric fill and metal vias. Each layer stack column includes a metal bit line over a nucleation line. Each metal via contacts one of the layer stack columns at its nucleation line. A low temperature dielectric liner extends along sidewalls of the layer stack columns. A non-conformal dielectric overlies the layer stack columns defining a plurality of air gaps between the layer stack columns.
    Type: Grant
    Filed: February 15, 2013
    Date of Patent: September 1, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Jayavel Pachamuthu, Hiroyuki Kinoshita, Vinod R. Purayath, George Matamis
  • Publication number: 20150236038
    Abstract: A first stack of alternating layers including first electrically conductive layers and first electrically insulating layers is formed with first stepped surfaces and a first dielectric material portion thereupon. Dielectric pillar structures including a dielectric metal oxide can be formed through the first stepped surfaces. Lower memory openings can be formed, and filled with a disposable material or a lower memory opening structure including a lower semiconductor channel and a doped semiconductor region. At least one dielectric material layer and a second stack of alternating layers including second electrically conductive layers and second electrically insulating layers can be sequentially formed. Upper memory openings can be formed through the second stack and the at least one dielectric material layer. A memory film and a semiconductor channel can be formed after removal of the disposable material, or an upper semiconductor channel can be formed on the doped semiconductor region.
    Type: Application
    Filed: February 2, 2015
    Publication date: August 20, 2015
    Inventors: Jayavel PACHAMUTHU, Johann ALSMEIER, Henry CHIEN
  • Patent number: 9099496
    Abstract: A stack can be patterned by a first etch process to form an opening defining sidewall surfaces of a patterned material stack. A masking layer can be non-conformally deposited on sidewalls of an upper portion of the patterned material stack, while not being deposited on sidewalls of a lower portion of the patterned material stack. The sidewalls of a lower portion of the opening can be laterally recessed employing a second etch process, which can include an isotropic etch component. The sidewalls of the upper portion of the opening can protrude inward toward the opening to form an overhang over the sidewalls of the lower portion of the opening. The overhang can be employed to form useful structures such as an negative offset profile in a floating gate device or vertically aligned control gate electrodes for vertical memory devices.
    Type: Grant
    Filed: August 29, 2014
    Date of Patent: August 4, 2015
    Assignee: SANDISK TECHNOLOGIES INC.
    Inventors: Ming Tian, Jayavel Pachamuthu, Atsushi Suyama, James Kai, Raghuveer S. Makala, Yao-Sheng Lee, Johann Alsmeier, Henry Chien, Masanori Terahara, Hirofumi Watatani
  • Patent number: 9030016
    Abstract: A semiconductor device including a plurality of copper interconnects. At least a first portion of the plurality of copper interconnects has a meniscus in a top surface. The semiconductor device also includes a plurality of air gaps, wherein each air gap of the plurality of air gaps is located between an adjacent pair of at least the first portion of the plurality of bit lines.
    Type: Grant
    Filed: September 10, 2013
    Date of Patent: May 12, 2015
    Assignee: Sandisk Technologies Inc.
    Inventors: Vinod R. Purayath, James K. Kai, Jayavel Pachamuthu, Jarrett Jun Liang, George Matamis
  • Patent number: 9023719
    Abstract: A method of fabricating a semiconductor device, such as a three-dimensional monolithic NAND memory string, includes etching a select gate electrode over a first gate insulating layer over a substrate to form an opening, forming a second gate insulating layer over the sidewalls of the opening, forming a sacrificial spacer layer over the second gate insulating layer on the sidewalls of the opening, and etching the first gate insulating layer over the bottom surface of the opening to expose the substrate, removing the sacrificial spacer layer to expose the second gate insulating layer over the sidewalls of the opening, and forming a protrusion comprising a semiconductor material within the opening and contacting the substrate, wherein the second gate insulating layer is located between the select gate electrode and first and second side surfaces of the protrusion.
    Type: Grant
    Filed: March 25, 2014
    Date of Patent: May 5, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Jayavel Pachamuthu, Johann Alsmeier, Raghuveer S. Makala, Yao-Sheng Lee
  • Publication number: 20150118811
    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 at least partially filling the lower portion of the memory openings with a sacrificial material. 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 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: Application
    Filed: December 30, 2014
    Publication date: April 30, 2015
    Inventors: Raghuveer S. Makala, Yao-Sheng Lee, Jayavel Pachamuthu, Johann Alsmeier, Henry Chien
  • Patent number: 8987089
    Abstract: A method of fabricating a memory device, such as a three-dimensional NAND string, includes forming a trench through a stack of alternating first and second material layers to expose a source region of a semiconductor channel, partially filling the trench with a protective material, removing at least a portion of the alternating second material layers to form recesses between the first material layers, forming a conductive material in the recesses to form control gate electrodes for a memory device, depositing an insulating material over the sidewalls and bottom of the trench, etching through the insulating material and the protective material to expose the semiconductor channel at the trench bottom while leaving the insulating material on the trench sidewalls, and filling the trench with a source line that electrically contacts the source region while the insulating material is between the source line and the control gate electrodes along the trench sidewalls.
    Type: Grant
    Filed: April 29, 2014
    Date of Patent: March 24, 2015
    Assignee: Sandisk Technologies Inc.
    Inventors: Jayavel Pachamuthu, Johann Alsmeier, Raghuveer S. Makala, Yao-Sheng Lee
  • Publication number: 20150079765
    Abstract: A method of fabricating a semiconductor device, such as a three-dimensional monolithic NAND memory string, includes etching a select gate electrode over a first gate insulating layer over a substrate to form an opening, forming a second gate insulating layer over the sidewalls of the opening, forming a sacrificial spacer layer over the second gate insulating layer on the sidewalls of the opening, and etching the first gate insulating layer over the bottom surface of the opening to expose the substrate, removing the sacrificial spacer layer to expose the second gate insulating layer over the sidewalls of the opening, and forming a protrusion comprising a semiconductor material within the opening and contacting the substrate, wherein the second gate insulating layer is located between the select gate electrode and first and second side surfaces of the protrusion.
    Type: Application
    Filed: March 25, 2014
    Publication date: March 19, 2015
    Applicant: SanDisk Technologies, Inc.
    Inventors: Jayavel Pachamuthu, Johann Alsmeier, Raghuveer S. Makala, Yao-Sheng Lee
  • Publication number: 20150076584
    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: Application
    Filed: March 25, 2014
    Publication date: March 19, 2015
    Inventors: Jayavel Pachamuthu, Johann Alsmeier, Raghuveer S. Makala, Yao-Sheng Lee
  • Publication number: 20150076585
    Abstract: A memory device includes a stack of material layers with a plurality of NAND strings extending through the stack, and a trench through the stack with a pair of sidewalls defining a width of the trench that is substantially constant or decreases from the top of the trench to a first depth and increases between a first depth and a second depth that is closer to the bottom of the trench than the first depth and the trench has an insulating material covering at least the trench sidewalls. Further embodiments include a memory device including a stack of material layers and an active memory cell region defined between a pair of trenches, and within the active region the stack comprises alternating layers of a first material and a second material, and outside of the active region the stack comprises alternating layers of the first material and a third material.
    Type: Application
    Filed: April 29, 2014
    Publication date: March 19, 2015
    Applicant: SanDisk Technologies, Inc.
    Inventors: Jayavel Pachamuthu, Johann Alsmeier, Raghuveer S. Makala, Yao-Sheng Lee
  • Publication number: 20150079743
    Abstract: A method of fabricating a memory device, such as a three-dimensional NAND string, includes forming a trench through a stack of alternating first and second material layers to expose a source region of a semiconductor channel, partially filling the trench with a protective material, removing at least a portion of the alternating second material layers to form recesses between the first material layers, forming a conductive material in the recesses to form control gate electrodes for a memory device, depositing an insulating material over the sidewalls and bottom of the trench, etching through the insulating material and the protective material to expose the semiconductor channel at the trench bottom while leaving the insulating material on the trench sidewalls, and filling the trench with a source line that electrically contacts the source region while the insulating material is between the source line and the control gate electrodes along the trench sidewalls.
    Type: Application
    Filed: April 29, 2014
    Publication date: March 19, 2015
    Applicant: SanDisk Technologies, Inc.
    Inventors: Jayavel Pachamuthu, Johann Alsmeier, Raghuveer S. Makala, Yao-Sheng Lee