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).

  • Publication number: 20140226393
    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: Application
    Filed: April 19, 2014
    Publication date: August 14, 2014
    Applicant: SANDISK 3D LLC
    Inventors: Roy E. Scheuerlein, George Samachisa
  • Patent number: 8780605
    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 7, 2013
    Date of Patent: July 15, 2014
    Assignee: SanDisk 3D LLC
    Inventors: Tianhong Yan, George Samachisa
  • Publication number: 20140192595
    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: Application
    Filed: January 13, 2014
    Publication date: July 10, 2014
    Applicant: SanDisk 3D LLC
    Inventor: George Samachisa
  • Patent number: 8765543
    Abstract: A method of making a monolithic three dimensional NAND string includes forming a stack of alternating layers of a first layer and a second layer over a substrate, where the first layer includes a conductive or semiconductor control gate material and the second layer includes an insulating material. The method also includes etching the stack to form at least one opening in the stack, selectively etching the first layer to form first recesses, forming a conductive or semiconductor liner having a clam shape in the first recesses, forming a blocking dielectric over the conductive or semiconductor liner in the first recesses, forming a plurality of discrete charge storage segments separated from each other in the first recesses over the blocking dielectric, forming a tunnel dielectric over a side wall of the discrete charge storage segments exposed in the at least one opening, and forming a semiconductor channel in the opening.
    Type: Grant
    Filed: October 11, 2013
    Date of Patent: July 1, 2014
    Assignee: SanDisk Technologies, Inc.
    Inventors: Johann Alsmeier, George Samachisa
  • Publication number: 20140175530
    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: February 26, 2014
    Publication date: June 26, 2014
    Applicant: SanDisk Technologies Inc.
    Inventors: Henry Chien, Johann Alsmeier, George Samachisa, Henry Chin, George Matamis, Yuan Zhang, James Kai, Vinod Purayath, Donovan Lee
  • Publication number: 20140179068
    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: Application
    Filed: January 7, 2014
    Publication date: June 26, 2014
    Applicant: SanDisk 3D LLC
    Inventors: George Samachisa, Johann Alsmeier
  • Patent number: 8750066
    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: October 2, 2013
    Date of Patent: June 10, 2014
    Assignee: Sandisk 3D LLC
    Inventors: Roy E. Scheuerlein, George Samachisa
  • Publication number: 20140043911
    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: Application
    Filed: October 18, 2013
    Publication date: February 13, 2014
    Applicant: SANDISK 3D LLC
    Inventors: George Samachisa, Luca Fasoli, Masaaki Higashitani, Roy Edwin Scheuerlein
  • Publication number: 20140045307
    Abstract: Monolithic, three dimensional NAND strings include 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 having a strip shape extending substantially parallel to the major surface of the substrate, the blocking dielectric comprising a plurality of blocking dielectric segments, a plurality of discrete charge storage segments, and a tunnel dielectric located between each one of the plurality of the discrete charge storage segments and the semiconductor channel.
    Type: Application
    Filed: October 11, 2013
    Publication date: February 13, 2014
    Applicant: SanDisk Technologies Inc.
    Inventors: Johann Alsmeier, George Samachisa
  • Publication number: 20140029356
    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: Application
    Filed: October 2, 2013
    Publication date: January 30, 2014
    Applicant: SANDISK 3D LLC
    Inventors: Roy E. Scheuerlein, George Samachisa
  • Publication number: 20140022848
    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: Application
    Filed: August 22, 2013
    Publication date: January 23, 2014
    Applicant: SANDISK 3D LLC
    Inventors: George Samachisa, Luca Fasoli, Yan Li, Tianhong Yan
  • Patent number: 8625322
    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: December 12, 2011
    Date of Patent: January 7, 2014
    Assignee: SanDisk 3D LLC
    Inventors: George Samachisa, Johann Alsmeier
  • Publication number: 20140001533
    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: Application
    Filed: December 7, 2012
    Publication date: January 2, 2014
    Applicant: SANDISK TECHNOLOGIES, INC.
    Inventors: Vinod Purayath, George Samachisa, George Matamis, James Kai, Yuan Zhang
  • Publication number: 20140001535
    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: Application
    Filed: December 7, 2012
    Publication date: January 2, 2014
    Applicant: SanDisk Technologies, Inc.
    Inventors: Vinod Purayath, George Samachisa, George Matamis, James Kai, Yuan Zhang
  • Publication number: 20130336038
    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: Application
    Filed: March 15, 2013
    Publication date: December 19, 2013
    Applicant: SanDisk 3D LLC
    Inventors: Raul Adrian Cernea, George Samachisa
  • Patent number: 8580639
    Abstract: Monolithic, three dimensional NAND strings include 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 having a strip shape extending substantially parallel to the major surface of the substrate, the blocking dielectric comprising a plurality of blocking dielectric segments, a plurality of discrete charge storage segments, and a tunnel dielectric located between each one of the plurality of the discrete charge storage segments and the semiconductor channel.
    Type: Grant
    Filed: May 2, 2013
    Date of Patent: November 12, 2013
    Assignee: SanDisk Technologies Inc.
    Inventors: Johann Alsmeier, George Samachisa
  • Patent number: 8575715
    Abstract: A storage system and method for forming a storage system that uses punch-through diodes as a steering element in series with a reversible resistivity-switching element is described. The punch-through diode allows bipolar operation of a cross-point memory array. The punch-through diode may have a symmetrical non-linear current/voltage relationship. The punch-through diode has a high current at high bias for selected cells and a low leakage current at low bias for unselected cells. Therefore, it is compatible with bipolar switching in cross-point memory arrays having resistive switching elements. The punch-through diode may be a N+/P?/N+ device or a P+/N?/P+ device.
    Type: Grant
    Filed: August 9, 2012
    Date of Patent: November 5, 2013
    Assignee: SanDisk 3D LLC
    Inventors: Andrei Mihnea, Deepak C. Sekar, George Samachisa, Roy Scheuerlein, Li Xiao
  • Patent number: 8576651
    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: January 20, 2012
    Date of Patent: November 5, 2013
    Assignee: Sandisk 3D LLC
    Inventors: Roy E. Scheuerlein, George Samachisa
  • Patent number: 8547720
    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: June 1, 2011
    Date of Patent: October 1, 2013
    Assignee: Sandisk 3D LLC
    Inventors: George Samachisa, Luca Fasoli, Masaaki Higashitani, Roy Edwin Scheuerlein
  • Publication number: 20130237024
    Abstract: Monolithic, three dimensional NAND strings include 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 having a strip shape extending substantially parallel to the major surface of the substrate, the blocking dielectric comprising a plurality of blocking dielectric segments, a plurality of discrete charge storage segments, and a tunnel dielectric located between each one of the plurality of the discrete charge storage segments and the semiconductor channel.
    Type: Application
    Filed: May 2, 2013
    Publication date: September 12, 2013
    Applicant: SanDisk Technologies Inc.
    Inventors: Johann Alsmeier, George Samachisa