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: 20130229846
    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: Application
    Filed: March 7, 2013
    Publication date: September 5, 2013
    Applicant: SanDisk 3D LLC
    Inventors: Henry Chien, Yao-Sheng Lee, George Samachisa, Johann Alsmeier
  • Patent number: 8526237
    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: June 1, 2011
    Date of Patent: September 3, 2013
    Assignee: SanDisk 3D LLC
    Inventors: George Samachisa, Luca Fasoli, Yan Li, Tianhong Yan
  • Patent number: 8520424
    Abstract: A memory device in a 3-D read and write memory includes memory cells. Each memory cell includes a resistance-switching memory element (RSME) in series with a steering element. The RSME has first and second resistance-switching layers on either side of a conductive intermediate layer, and first and second electrodes at either end of the RSME. The first and second resistance-switching layers can both have a bipolar or unipolar switching characteristic. In a set or reset operation of the memory cell, an ionic current flows in the resistance-switching layers, contributing to a switching mechanism. An electron flow, which does not contribute to the switching mechanism, is reduced due to scattering by the conductive intermediate layer, to avoid damage to the steering element. Particular materials and combinations of materials for the different layers of the RSME are provided.
    Type: Grant
    Filed: June 9, 2011
    Date of Patent: August 27, 2013
    Assignee: SanDisk 3D LLC
    Inventors: Franz Kreupl, Abhijit Bandyopadhyay, Yung-Tin Chen, Chu-Chen Fu, Wipul Pemsiri Jayasekara, James Kai, Raghuveer S. Makala, Peter Rabkin, George Samachisa, Jingyan Zhang
  • Publication number: 20130188431
    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: January 20, 2012
    Publication date: July 25, 2013
    Inventors: Roy E. Scheuerlein, George Samachisa
  • Patent number: 8462580
    Abstract: A memory system includes a plurality of non-volatile storage elements that each comprise a diode (or other steering device) in series with reversible resistance-switching material. One or more circuits in the memory system program the non-volatile storage elements by changing the reversible resistance-switching material of one or more non-volatile storage elements to a first resistance state. The memory system can also change the reversible resistance-switching material of one or more of the non-volatile storage elements from the first resistance state to a second resistance state by applying one or more pairs of opposite polarity voltage conditions (e.g., pulses) to the respective diodes (or other steering devices) such that current flows in the diodes (or other steering devices) without operating the diodes (or other steering devices) in breakdown condition.
    Type: Grant
    Filed: November 17, 2010
    Date of Patent: June 11, 2013
    Assignee: SanDisk 3D LLC
    Inventors: Peter Rabkin, George Samachisa, Roy E. Scheuerlein
  • Patent number: 8461000
    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: December 4, 2012
    Date of Patent: June 11, 2013
    Assignee: SanDisk Technologies Inc.
    Inventors: Johann Alsmeier, George Samachisa
  • Patent number: 8395942
    Abstract: A method of making a NAND string includes forming a semiconductor layer over a major surface of a substrate, patterning the semiconductor layer into an elongated nanowire shaped channel extending substantially parallel to the major surface of the substrate, forming a tunneling dielectric layer over the channel, forming a plurality of charge storage regions over the tunneling dielectric layer and undercutting the channel using the plurality of charge storage regions as mask. The channel has a narrower width than each charge storage region width, and an overhanging portion of each of the plurality of charge storage regions overhangs the channel. The method also includes forming a blocking dielectric layer over the plurality of charge storage regions, such that the blocking dielectric layer fills a space below the overhanging portion of each of the plurality of charge storage regions and forming a plurality of control gates over the blocking dielectric layer.
    Type: Grant
    Filed: August 2, 2010
    Date of Patent: March 12, 2013
    Assignee: SanDisk Technologies Inc.
    Inventors: George Samachisa, Johann Alsmeier, Andrei Mihnea
  • Patent number: 8355271
    Abstract: A memory system includes a plurality of non-volatile storage elements that each comprise a diode (or other steering device) in series with reversible resistance-switching material. One or more circuits in the memory system program the non-volatile storage elements by changing the reversible resistance-switching material of one or more non-volatile storage elements to a first resistance state. The memory system can also change the reversible resistance-switching material of one or more of the non-volatile storage elements from the first resistance state to a second resistance state by applying one or more pairs of opposite polarity voltage conditions (e.g., pulses) to the respective diodes (or other steering devices) such that current flows in the diodes (or other steering devices) without operating the diodes (or other steering devices) in breakdown condition.
    Type: Grant
    Filed: November 17, 2010
    Date of Patent: January 15, 2013
    Assignee: SanDisk 3D LLC
    Inventors: Peter Rabkin, George Samachisa, Roy E. Scheuerlein
  • Patent number: 8349681
    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: June 30, 2010
    Date of Patent: January 8, 2013
    Assignee: SanDisk Technologies Inc.
    Inventors: Johann Alsmeier, George Samachisa
  • Patent number: 8351236
    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: March 26, 2010
    Date of Patent: January 8, 2013
    Assignee: SanDisk 3D LLC
    Inventors: Tianhong Yan, George Samachisa
  • Patent number: 8351243
    Abstract: A nonvolatile memory device with a first conductor extending in a first direction and a semiconductor element above the first conductor. The semiconductor element includes a source, a drain and a channel of a field effect transistor (JFET or MOSFET). The nonvolatile memory device also includes a second conductor above the semiconductor element, the second conductor extending in a second direction. The nonvolatile memory device also includes a resistivity switching material disposed between the first conductor and the semiconductor element or between the second conductor and the semiconductor element. The JFET or MOSFET includes a gate adjacent to the channel, and the MOSFET gate being self-aligned with the first conductor.
    Type: Grant
    Filed: November 16, 2010
    Date of Patent: January 8, 2013
    Assignee: SanDisk 3D LLC
    Inventors: Andrei Mihnea, George Samachisa
  • Publication number: 20120302029
    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: Application
    Filed: August 9, 2012
    Publication date: November 29, 2012
    Inventors: Andrei Mihnea, Deepak C. Sekar, George Samachisa, Roy Scheuerlein, Li Xiao
  • Patent number: 8274130
    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: October 20, 2009
    Date of Patent: September 25, 2012
    Assignee: SanDisk 3D LLC
    Inventors: Andrei Mihnea, Deepak C. Sekar, George Samachisa, Roy Scheuerlein, Li Xiao
  • Publication number: 20120147649
    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: December 12, 2011
    Publication date: June 14, 2012
    Inventors: George Samachisa, Johann Alsmeier
  • Publication number: 20120147650
    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: December 12, 2011
    Publication date: June 14, 2012
    Inventors: George Samachisa, Johann Alsmeier
  • Patent number: 8199576
    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 double-global-bit-line architecture provides a pair of global bit lines for each bit lines for accessing a row of memory elements in parallel. A first one of each pair allows the local bit lines of the row to be sensed while a second one of each pair allows local bit lines in an adjacent row to be set to a definite voltage so as to eliminate leakage currents between adjacent rows of local bit lines.
    Type: Grant
    Filed: March 26, 2010
    Date of Patent: June 12, 2012
    Assignee: SanDisk 3D LLC
    Inventors: Luca Fasoli, George Samachisa
  • Publication number: 20120120709
    Abstract: A nonvolatile memory device with a first conductor extending in a first direction and a semiconductor element above the first conductor. The semiconductor element includes a source, a drain and a channel of a field effect transistor (JFET or MOSFET). The nonvolatile memory device also includes a second conductor above the semiconductor element, the second conductor extending in a second direction. The nonvolatile memory device also includes a resistivity switching material disposed between the first conductor and the semiconductor element or between the second conductor and the semiconductor element. The JFET or MOSFET includes a gate adjacent to the channel, and the MOSFET gate being self-aligned with the first conductor.
    Type: Application
    Filed: November 16, 2010
    Publication date: May 17, 2012
    Applicant: SanDisk 3D LLC
    Inventors: Andrei Mihnea, George Samachisa
  • Publication number: 20120120711
    Abstract: A memory system includes a plurality of non-volatile storage elements that each comprise a diode (or other steering device) in series with reversible resistance-switching material. One or more circuits in the memory system program the non-volatile storage elements by changing the reversible resistance-switching material of one or more non-volatile storage elements to a first resistance state. The memory system can also change the reversible resistance-switching material of one or more of the non-volatile storage elements from the first resistance state to a second resistance state by applying one or more pairs of opposite polarity voltage conditions (e.g., pulses) to the respective diodes (or other steering devices) such that current flows in the diodes (or other steering devices) without operating the diodes (or other steering devices) in breakdown condition.
    Type: Application
    Filed: November 17, 2010
    Publication date: May 17, 2012
    Inventors: Peter Rabkin, George Samachisa, Roy E. Scheuerlein
  • Publication number: 20120120710
    Abstract: A memory system includes a plurality of non-volatile storage elements that each comprise a diode (or other steering device) in series with reversible resistance-switching material. One or more circuits in the memory system program the non-volatile storage elements by changing the reversible resistance-switching material of one or more non-volatile storage elements to a first resistance state. The memory system can also change the reversible resistance-switching material of one or more of the non-volatile storage elements from the first resistance state to a second resistance state by applying one or more pairs of opposite polarity voltage conditions (e.g., pulses) to the respective diodes (or other steering devices) such that current flows in the diodes (or other steering devices) without operating the diodes (or other steering devices) in breakdown condition.
    Type: Application
    Filed: November 17, 2010
    Publication date: May 17, 2012
    Inventors: Peter Rabkin, George Samachisa, Roy E. Scheuerlein
  • Publication number: 20120001249
    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: June 30, 2010
    Publication date: January 5, 2012
    Applicant: SanDisk Corporation
    Inventors: Johann Alsmeier, George Samachisa