Patents by Inventor George Samachisa

George Samachisa 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: 9245629
    Abstract: A three-dimensional array of memory elements is formed across multiple layers of planes positioned at different distances above a semiconductor substrate. The memory elements reversibly change a level of electrical conductance in response to a voltage difference being applied across them. The three-dimensional array includes a two-dimensional array of pillar lines from the substrate through the multiple layers of planes. A first set of pillar lines acts as local bit lines for accessing the memory elements together with an array of word lines on each plane. A second set of pillar lines is connected to the word lines. An array of metal lines on the substrate is switchable connected to the pillar lines to provide access to the first and second sets of pillar lines, thereby to provide access respectively to the bit lines and word lines of the three-dimensional array.
    Type: Grant
    Filed: October 18, 2013
    Date of Patent: January 26, 2016
    Assignee: SANDISK 3D LLC
    Inventors: George Samachisa, Luca Fasoli, Masaaki Higashitani, Roy Edwin Scheuerlein
  • Patent number: 9236122
    Abstract: A non-volatile storage device comprises: a substrate; a monolithic three dimensional array of memory cells; word lines connected to the memory cells; global bit lines; vertical bit lines connected to the memory cells; and a plurality of double gated vertically oriented select devices. The double gated vertically oriented select devices are connected to the vertical bit lines and the global bit lines so that when the double gated vertically oriented select devices are activated the vertical bit lines are in communication with the global bit lines. Each double gated vertically oriented select device has two gates that are offset from each other with respect to distance to the substrate. Both gates for the double gated vertically oriented select device need be in an “on” condition for the double gated vertically oriented select devices to be activated.
    Type: Grant
    Filed: July 24, 2014
    Date of Patent: January 12, 2016
    Assignee: SANDISK 3D LLC
    Inventors: Tianhong Yan, George Samachisa, Tz-yi Liu, Tim Chen, Perumal Ratnam
  • Patent number: 9227456
    Abstract: A three-dimensional memory is formed as an array of memory elements across multiple layers positioned at different distances above a semiconductor substrate. Cylindrical stacks of memory elements are formed where a cylindrical opening has read/write material deposited along its wall, and a cylindrical vertical bit line formed along its central axis. Memory elements formed on either side of such a cylinder may include sheet electrodes that extend into the read/write material.
    Type: Grant
    Filed: March 7, 2013
    Date of Patent: January 5, 2016
    Assignee: SanDisk 3D LLC
    Inventors: Henry Chien, Yao-Sheng Lee, George Samachisa, Johann Alsmeier
  • Patent number: 9190134
    Abstract: A three-dimensional array especially adapted for memory elements that reversibly change a level of electrical conductance in response to a voltage difference being applied across them. Memory elements are formed across a plurality of planes positioned different distances above a semiconductor substrate. A two-dimensional array of bit lines to which the memory elements of all planes are connected is oriented vertically from the substrate and through the plurality of planes. A single-sided word line architecture provides a word line exclusively for each row of memory elements instead of sharing one word line between two rows of memory elements thereby avoids linking the memory element across the array across the word lines. While the row of memory elements is also being accessed by a corresponding row of local bit lines, there is no extension of coupling between adjacent rows of local bit lines and therefore leakage currents beyond the word line.
    Type: Grant
    Filed: January 13, 2014
    Date of Patent: November 17, 2015
    Assignee: SANDISK 3D LLC
    Inventor: George Samachisa
  • Patent number: 9165940
    Abstract: A method of making a monolithic three dimensional NAND string, including providing a stack of alternating first material layers and second material layers different from the first material layer over a substrate, the stack comprising at least one opening containing a charge storage material comprising a silicide layer, a tunnel dielectric on the charge storage material in the at least one opening, and a semiconductor channel on the tunnel dielectric in the at least one opening, selectively removing the second material layers without removing the first material layers from the stack and forming control gates between the first material layers.
    Type: Grant
    Filed: November 12, 2014
    Date of Patent: October 20, 2015
    Assignee: SANDISK TECHNOLOGIES INC.
    Inventors: Henry Chien, Johann Alsmeier, George Samachisa, Henry Chin, George Matamis, Yuan Zhang, James Kai, Vinod Purayath, Donovan Lee
  • Patent number: 9147439
    Abstract: In a 3D nonvolatile memory with memory elements arranged in a three-dimensional pattern defined by rectangular coordinates having x, y and z-directions and with a plurality of parallel planes from a bottom plane to a top plane stacked in the z-direction over a semiconductor substrate; a plurality of local bit lines elongated in the z-direction through the plurality of layers and arranged in a two-dimensional rectangular array of bit line pillars having rows in the x-direction and columns in the y-direction; the 3D nonvolatile memory further having a plurality of staircase word lines spaced apart in the y-direction and between and separated from the plurality of bit line pillars at a plurality of crossings, individual staircase word lines each having a series of alternating steps and risers elongated respectively in the x-direction and z-direction traversing across the plurality of planes in the z-direction with a segment in each plane.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: September 29, 2015
    Assignee: SANDISK 3D LLC
    Inventors: Raul Adrian Cernea, George Samachisa
  • Patent number: 9064547
    Abstract: A 3D array of nonvolatile memory has each read/write element accessed at a crossing between a word line and a bit line. The read/write element forms a tubular electrode having an outside shell of R/W material enclosing an oxide core. In a rectangular form, one side of the electrode contacts the word line and another side contacts the bit line. The thickness of the shell rather than its surface areas in contact with the word line and bit line determines the conduction cross-section and therefore the resistance. By adjusting the thickness of the shell, independent of its contact area with either the word line or bit line, each read/write element can operate with a much increased resistance and therefore much reduced current. Processes to manufacture a 3D array with such tubular R/W elements 3D array are also described.
    Type: Grant
    Filed: March 4, 2014
    Date of Patent: June 23, 2015
    Assignee: SanDisk 3D LLC
    Inventors: Raul Adrian Cernea, Yung-Tin Chen, George Samachisa
  • Patent number: 9047983
    Abstract: Methods for operating a semiconductor memory array including dynamically adjusting control line voltages (e.g., unselected word line or unselected bit line voltages) based on one or more array conditions associated with the semiconductor memory array are described. The one or more array conditions may include a temperature associated with the semiconductor memory array or a particular number of write cycles associated with the semiconductor memory array. In some embodiments, an intermediate voltage is generated based on the one or more array conditions and applied to the unselected word lines and the unselected bit lines of the semiconductor memory array. The one or more intermediate voltages may be generated such that a first voltage difference across unselected memory cells sharing a selected word line is different from a second voltage difference across other unselected memory cells sharing a selected bit line based on the one or more array conditions.
    Type: Grant
    Filed: April 19, 2014
    Date of Patent: June 2, 2015
    Assignee: SANDISK 3D LLC
    Inventors: Roy E. Scheuerlein, George Samachisa
  • Patent number: 9029936
    Abstract: A memory device includes a semiconductor channel, a tunnel dielectric layer located over the semiconductor channel, a first charge trap including a plurality of electrically conductive nanodots located over the tunnel dielectric layer, dielectric separation layer located over the nanodots, a second charge trap including a continuous metal layer located over the separation layer, a blocking dielectric located over the second charge trap, and a control gate located over the blocking dielectric.
    Type: Grant
    Filed: December 7, 2012
    Date of Patent: May 12, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Vinod Purayath, George Samachisa, George Matamis, James Kai, Yuan Zhang
  • Publication number: 20150072488
    Abstract: A method of making a monolithic three dimensional NAND string, including providing a stack of alternating first material layers and second material layers different from the first material layer over a substrate, the stack comprising at least one opening containing a charge storage material comprising a silicide layer, a tunnel dielectric on the charge storage material in the at least one opening, and a semiconductor channel on the tunnel dielectric in the at least one opening, selectively removing the second material layers without removing the first material layers from the stack and forming control gates between the first material layers.
    Type: Application
    Filed: November 12, 2014
    Publication date: March 12, 2015
    Inventors: Henry Chien, Johann Alsmeier, George Samachisa, Henry Chin, George Matamis, Yuan Zhang, James Kai, Vinod Purayath, Donovan Lee
  • Patent number: 8958228
    Abstract: A three-dimensional memory is formed as an array of memory elements that are formed across multiple layers of planes positioned at different distances above a semiconductor substrate. The memory elements reversibly change a level of electrical conductance in response to a voltage difference being applied across them. The three-dimensional array includes a two-dimensional array of pillar lines acting as local vertical bit lines through the multiple layers of planes which together with arrays of word lines on each plane are used to access the memory elements. The three-dimensional memory is formed over a CMOS substrate with an intermediate pillar select layer. The pillar select layer is formed with a plurality of pillar select devices which are switching transistors formed outside the CMOS and serve to switch selected rows of pillar lines to corresponding metal lines on the substrate.
    Type: Grant
    Filed: July 24, 2014
    Date of Patent: February 17, 2015
    Assignee: Sandisk 3D LLC
    Inventors: George Samachisa, Johann Alsmeier
  • Publication number: 20150036414
    Abstract: A non-volatile storage device comprises: a substrate; a monolithic three dimensional array of memory cells; word lines connected to the memory cells; global bit lines; vertical bit lines connected to the memory cells; and a plurality of double gated vertically oriented select devices. The double gated vertically oriented select devices are connected to the vertical bit lines and the global bit lines so that when the double gated vertically oriented select devices are activated the vertical bit lines are in communication with the global bit lines. Each double gated vertically oriented select device has two gates that are offset from each other with respect to distance to the substrate. Both gates for the double gated vertically oriented select device need be in an “on” condition for the double gated vertically oriented select devices to be activated.
    Type: Application
    Filed: July 24, 2014
    Publication date: February 5, 2015
    Inventors: Tianhong Yan, George Samachisa, Tz-yi Liu, Tim Chen, Perumal Ratnam
  • Patent number: 8928061
    Abstract: A monolithic three dimensional NAND string includes a semiconductor channel located over a substrate, a plurality of control gates extending substantially parallel to the major surface of the substrate including a first control gate located in a first device level and a second control gate located in a second device level located over the substrate and below the first device level, a charge storage material including a silicide layer located in the first device level and in the second device level, a blocking dielectric located between the charge storage material and the plurality of control gates, and a tunnel dielectric located between the charge storage material and the semiconductor channel. The tunnel dielectric has a straight sidewall, portions of the blocking dielectric have a clam shape, and each of the plurality of control gates is located at least partially in an opening in the clam-shaped portion of the blocking dielectric.
    Type: Grant
    Filed: February 26, 2014
    Date of Patent: January 6, 2015
    Assignee: SanDisk Technologies, Inc.
    Inventors: Henry Chien, Johann Alsmeier, George Samachisa, Henry Chin, George Matamis, Yuan Zhang, James Kai, Vinod Purayath, Donovan Lee
  • Publication number: 20140335671
    Abstract: A three-dimensional memory is formed as an array of memory elements that are formed across multiple layers of planes positioned at different distances above a semiconductor substrate. The memory elements reversibly change a level of electrical conductance in response to a voltage difference being applied across them. The three-dimensional array includes a two-dimensional array of pillar lines acting as local vertical bit lines through the multiple layers of planes which together with arrays of word lines on each plane are used to access the memory elements. The three-dimensional memory is formed over a CMOS substrate with an intermediate pillar select layer. The pillar select layer is formed with a plurality of pillar select devices which are switching transistors formed outside the CMOS and serve to switch selected rows of pillar lines to corresponding metal lines on the substrate.
    Type: Application
    Filed: July 24, 2014
    Publication date: November 13, 2014
    Inventors: George Samachisa, Johann Alsmeier
  • Publication number: 20140254231
    Abstract: A 3D array of nonvolatile memory has each read/write element accessed at a crossing between a word line and a bit line. The read/write element forms a tubular electrode having an outside shell of R/W material enclosing an oxide core. In a rectangular form, one side of the electrode contacts the word line and another side contacts the bit line. The thickness of the shell rather than its surface areas in contact with the word line and bit line determines the conduction cross-section and therefore the resistance. By adjusting the thickness of the shell, independent of its contact area with either the word line or bit line, each read/write element can operate with a much increased resistance and therefore much reduced current. Processes to manufacture a 3D array with such tubular R/W elements 3D array are also described.
    Type: Application
    Filed: March 4, 2014
    Publication date: September 11, 2014
    Applicant: SanDisk 3D LLC
    Inventors: Raul Adrian Cernea, Yung-Tin Chen, George Samachisa
  • Publication number: 20140252447
    Abstract: A memory device and a method of making a memory device that includes a semiconductor channel, a tunnel dielectric layer located over the semiconductor channel, a floating gate located over the tunnel dielectric layer, the floating gate comprising a continuous layer of an electrically conductive material and at least one protrusion of an electrically conductive material facing the tunnel dielectric layer and electrically shorted to the continuous layer, a blocking dielectric region located over the floating gate, and a control gate located over the blocking dielectric layer.
    Type: Application
    Filed: March 11, 2013
    Publication date: September 11, 2014
    Applicant: SANDISK TECHNOLOGIES, INC.
    Inventors: Donovan Lee, James K. Kai, George Samachisa, Henry Chien, George Matamis, Vinod R. Purayath
  • Patent number: 8824191
    Abstract: A three-dimensional array is especially adapted for memory elements that reversibly change a level of electrical conductance in response to a voltage difference being applied across them. Memory elements are formed across a plurality of planes positioned different distances above a semiconductor substrate. A two-dimensional array of bit lines to which the memory elements of all planes are connected is oriented vertically from the substrate and through the plurality of planes. During sensing, to compensate for word line resistance, a sense amplifier references a stored reference value during sensing of a memory element at a given location of the word line. A layout with a row of sense amplifiers between two memory arrays is provided to facilitate the referencing. A selected memory element is reset without resetting neighboring ones when it is subject to a bias voltage under predetermined conditions.
    Type: Grant
    Filed: August 22, 2013
    Date of Patent: September 2, 2014
    Assignee: Sandisk 3D LLC
    Inventors: George Samachisa, Luca Fasoli, Yan Li, Tianhong Yan
  • Patent number: 8824183
    Abstract: A three-dimensional memory is formed as an array of memory elements that are formed across multiple layers of planes positioned at different distances above a semiconductor substrate. The memory elements reversibly change a level of electrical conductance in response to a voltage difference being applied across them. The three-dimensional array includes a two-dimensional array of pillar lines acting as local vertical bit lines through the multiple layers of planes which together with arrays of word lines on each plane are used to access the memory elements. The three-dimensional memory is formed over a CMOS substrate with an intermediate pillar select layer. The pillar select layer is formed with a plurality of pillar select devices which are switching transistors formed outside the CMOS and serve to switch selected rows of pillar lines to corresponding metal lines on the substrate.
    Type: Grant
    Filed: December 12, 2011
    Date of Patent: September 2, 2014
    Assignee: Sandisk 3D LLC
    Inventors: George Samachisa, Johann Alsmeier
  • Patent number: 8822288
    Abstract: A method of fabricating a memory device includes providing multiple coatings of nanodots on a tunnel dielectric layer to form a floating gate layer having a high nanodot density. The memory device may have a nanodot-containing floating gate layer with a density greater than 4×1012 dots/cm2. Further methods include forming an oxidation barrier layer, such as a silicon nitride shell, over a surface of the nanodots, and depositing a dielectric material over the nanodots to form a floating gate layer.
    Type: Grant
    Filed: December 7, 2012
    Date of Patent: September 2, 2014
    Assignee: Sandisk Technologies Inc.
    Inventors: Vinod Purayath, George Samachisa, George Matamis, James Kai, Yuan Zhang
  • Patent number: 8817514
    Abstract: A three-dimensional array read/write (R/W) memory elements is formed across multiple layers of planes positioned at different distances above a semiconductor substrate. It is preferable to operate the R/W elements with low current and high resistive states. The resistance of these resistive states depends also on the dimension of the R/W elements and is predetermined by the process technology. A sheet electrode in series with the R/W element and a method of forming it provide another degree of freedom to adjust the resistance of the R/W memory element. The thickness of the sheet electrode is adjusted to obtain a reduced cross-sectional contact in the circuit path from the word line to the bit line. This allows the R/W memory element to have a much increased resistance and therefore to operate with much reduced currents. The sheet electrode is formed with little increase in cell size.
    Type: Grant
    Filed: January 7, 2014
    Date of Patent: August 26, 2014
    Assignee: SanDisk 3D LLC
    Inventors: George Samachisa, Johann Alsmeier