Patents by Inventor Durai Vishak Nirmal Ramaswamy

Durai Vishak Nirmal Ramaswamy 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: 20180005681
    Abstract: Methods, systems, and devices for memory array operation are described. A series of pulses may be applied to a fatigued memory cell to improve performance of memory cell. For example, a ferroelectric memory cell may enter a fatigue state after a number of access operations are performed at an access rate. After the number of access operations have been performed at the access rate, a fatigue state of the ferroelectric memory cell may be identified and the series of pulses may be applied to the ferroelectric capacitor at a different (e.g., higher) rate. For instance, a delay between pulses of the series of pulses may be shorter than the delay between access operations of the ferroelectric memory cell.
    Type: Application
    Filed: August 31, 2017
    Publication date: January 4, 2018
    Inventors: Alessandro Calderoni, Durai Vishak Nirmal Ramaswamy
  • Publication number: 20170373198
    Abstract: A ferroelectric field effect transistor comprises a semiconductive channel comprising opposing sidewalls and an elevationally outermost top. A source/drain region is at opposite ends of the channel. A gate construction of the transistor comprises inner dielectric extending along the channel top and laterally along the channel sidewalls. Inner conductive material is elevationally and laterally outward of the inner dielectric and extends along the channel top and laterally along the channel sidewalls. Outer ferroelectric material is elevationally outward of the inner conductive material and extends along the channel top. Outer conductive material is elevationally outward of the outer ferroelectric material and extends along the channel. Other constructions and methods are disclosed.
    Type: Application
    Filed: August 15, 2017
    Publication date: December 28, 2017
    Inventors: Durai Vishak Nirmal Ramaswamy, Kirk D. Prall
  • Patent number: 9853211
    Abstract: A method of forming an array of cross point memory cells comprises forming spaced conductive lower electrode pillars for individual of the memory cells being formed along and elevationally over spaced lower first lines. Walls cross elevationally over the first lines and between the electrode pillars that are along the first lines. The electrode pillars and walls form spaced openings between the first lines. The openings are lined with programmable material of the memory cells being formed to less-than-fill the openings with the programmable material. Conductive upper electrode material is formed over the programmable material within remaining volume of the openings and spaced upper second lines are formed which cross the first lines elevationally over the conductive upper electrode material that is within the openings.
    Type: Grant
    Filed: July 24, 2015
    Date of Patent: December 26, 2017
    Assignee: Micron Technology, Inc.
    Inventors: Scott E. Sills, Durai Vishak Nirmal Ramaswamy
  • Publication number: 20170365339
    Abstract: Memory programming methods and memory systems are described. One example memory programming method includes first applying a first signal to a memory cell to attempt to program the memory cell to a desired state, wherein the first signal corresponds to the desired state, after the first applying, determining that the memory cell failed to place in the desired state, after the determining, second applying a second signal to the memory cell, wherein the second signal corresponds to another state which is different than the desired state, and after the second applying, third applying a third signal to the memory cell to program the memory cell to the desired state, wherein the third signal corresponds to the desired state. Additional method and apparatus are described.
    Type: Application
    Filed: August 30, 2017
    Publication date: December 21, 2017
    Applicant: Micron Technology, Inc.
    Inventors: Jonathan Strand, Adam Johnson, Xiaonan Chen, Durai Vishak Nirmal Ramaswamy
  • Publication number: 20170365323
    Abstract: Methods, systems, and devices for operating a ferroelectric memory cell or cells are described. A cell may be written with a value that is intended to convey a different logic state than may typically be associated with the value. For example, a cell that has stored a charge associated with one logic state for a time period may be re-written to store a different charge, and the re-written cell may still be read to have the originally stored logic state. An indicator may be stored in a latch to indicate whether the logic state currently stored by the cell is the intended logic state of the cell. A cell may, for example, be re-written with an opposite value periodically, based on the occurrence of an event, or based on a determination that the cell has stored one value (or charge) for a certain time period.
    Type: Application
    Filed: July 10, 2017
    Publication date: December 21, 2017
    Inventors: Alessandro Calderoni, Durai Vishak Nirmal Ramaswamy, Kirk Prall, Ferdinando Bedeschi
  • Patent number: 9842839
    Abstract: A method of forming an array of capacitors and access transistors there-above comprises forming access transistor trenches partially into insulative material. The trenches individually comprise longitudinally-spaced masked portions and longitudinally-spaced openings in the trenches longitudinally between the masked portions. The trench openings have walls therein extending longitudinally in and along the individual trench openings against laterally-opposing sides of the trenches. At least some of the insulative material that is under the trench openings is removed through bases of the trench openings between the walls and the masked portions to form individual capacitor openings in the insulative material that is lower than the walls. Individual capacitors are formed in the individual capacitor openings. A line of access transistors is formed in the individual trenches. The line of access transistors electrically couples to the individual capacitors that are along that line.
    Type: Grant
    Filed: January 12, 2017
    Date of Patent: December 12, 2017
    Assignee: Micron Technology, Inc.
    Inventors: Scott E. Sills, Durai Vishak Nirmal Ramaswamy
  • Patent number: 9837420
    Abstract: A method of forming a tier of an array of memory cells within an array area, the memory cells individually comprising a capacitor and an elevationally-extending transistor, the method comprising using two, and only two, sacrificial masking steps within the array area of the tier in forming the memory cells. Other methods are disclosed, as are structures independent of method of fabrication.
    Type: Grant
    Filed: January 10, 2017
    Date of Patent: December 5, 2017
    Assignee: Micron Technology, Inc.
    Inventor: Durai Vishak Nirmal Ramaswamy
  • Publication number: 20170345831
    Abstract: Some embodiments include a ferroelectric device comprising ferroelectric material adjacent an electrode. The device includes a semiconductor material-containing region along a surface of the ferroelectric material nearest the electrode. The semiconductor material-containing region has a higher concentration of semiconductor material than a remainder of the ferroelectric material. The device may be, for example, a transistor or a capacitor. The device may be incorporated into a memory array. Some embodiments include a method of forming a ferroelectric capacitor. An oxide-containing ferroelectric material is formed over a first electrode. A second electrode is formed over the oxide-containing ferroelectric material. A semiconductor material-enriched portion of the oxide-containing ferroelectric material is formed adjacent the second electrode.
    Type: Application
    Filed: May 25, 2016
    Publication date: November 30, 2017
    Inventors: Ashonita A. Chavan, Ramanathan Gandhi, Beth R. Cook, Durai Vishak Nirmal Ramaswamy
  • Publication number: 20170330881
    Abstract: A method of forming an array of cross point memory cells comprises using two, and only two, masking steps to collectively pattern within the array spaced lower first lines, spaced upper second lines which cross the first lines, and individual programmable devices between the first lines and the second lines where such cross that have an upwardly open generally U-shape vertical cross-section of programmable material laterally between immediately adjacent of the first lines beneath individual of the upper second lines. Arrays of cross point memory cells independent of method of manufacture are disclosed.
    Type: Application
    Filed: May 11, 2016
    Publication date: November 16, 2017
    Inventor: Durai Vishak Nirmal Ramaswamy
  • Publication number: 20170309322
    Abstract: Some embodiments include a ferroelectric transistor. The transistor has gate dielectric material configured as a first container, with the first container having a first inner surface. Metal-containing material is configured as a second container nested within said first container. The second container has a second inner surface with an area less than the first inner surface. Ferroelectric material is configured as a third container nested within the second container. The third container has a third inner surface with an area less than the second inner surface. Gate material is within the third container. Some embodiments include memory arrays having ferroelectric transistors as memory cells. Some embodiments include methods of writing/reading relative to memory cells of memory arrays when the memory cells are metal-ferroelectric-metal-insulator-semiconductor (MFMIS) transistors.
    Type: Application
    Filed: April 20, 2016
    Publication date: October 26, 2017
    Inventors: Durai Vishak Nirmal Ramaswamy, Wayne Kinney
  • Patent number: 9799707
    Abstract: Some embodiments include memory structures having a diode over a memory cell. The memory cell can include programmable material between a pair of electrodes, with the programmable material containing a multivalent metal oxide directly against a high-k dielectric. The diode can include a first diode electrode directly over one of the memory cell electrodes and electrically coupled with the memory cell electrode, and can include a second diode electrode laterally outward of the first diode electrode and not directly over the memory cell. Some embodiments include memory arrays comprising the memory structures, and some embodiments include methods of making the memory structures.
    Type: Grant
    Filed: July 14, 2016
    Date of Patent: October 24, 2017
    Assignee: Micron Technology, Inc.
    Inventors: Durai Vishak Nirmal Ramaswamy, Mark S. Korber
  • Patent number: 9786349
    Abstract: Methods, systems, and devices for memory array operation are described. A series of pulses may be applied to a fatigued memory cell to improve performance of memory cell. For example, a ferroelectric memory cell may enter a fatigue state after a number of access operations are performed at an access rate. After the number of access operations have been performed at the access rate, a fatigue state of the ferroelectric memory cell may be identified and the series of pulses may be applied to the ferroelectric capacitor at a different (e.g., higher) rate. For instance, a delay between pulses of the series of pulses may be shorter than the delay between access operations of the ferroelectric memory cell.
    Type: Grant
    Filed: July 1, 2016
    Date of Patent: October 10, 2017
    Assignee: Micron Technology, Inc.
    Inventors: Alessandro Calderoni, Durai Vishak Nirmal Ramaswamy
  • Patent number: 9773551
    Abstract: Memory programming methods and memory systems are described. One example memory programming method includes first applying a first signal to a memory cell to attempt to program the memory cell to a desired state, wherein the first signal corresponds to the desired state, after the first applying, determining that the memory cell failed to place in the desired state, after the determining, second applying a second signal to the memory cell, wherein the second signal corresponds to another state which is different than the desired state, and after the second applying, third applying a third signal to the memory cell to program the memory cell to the desired state, wherein the third signal corresponds to the desired state. Additional method and apparatus are described.
    Type: Grant
    Filed: January 4, 2016
    Date of Patent: September 26, 2017
    Assignee: Micron Technology, Inc.
    Inventors: Jonathan Strand, Adam Johnson, Xiaonan Chen, Durai Vishak Nirmal Ramaswamy
  • Patent number: 9761715
    Abstract: A ferroelectric field effect transistor comprises a semiconductive channel comprising opposing sidewalls and an elevationally outermost top. A source/drain region is at opposite ends of the channel. A gate construction of the transistor comprises inner dielectric extending along the channel top and laterally along the channel sidewalls. Inner conductive material is elevationally and laterally outward of the inner dielectric and extends along the channel top and laterally along the channel sidewalls. Outer ferroelectric material is elevationally outward of the inner conductive material and extends along the channel top. Outer conductive material is elevationally outward of the outer ferroelectric material and extends along the channel. Other constructions and methods are disclosed.
    Type: Grant
    Filed: January 25, 2016
    Date of Patent: September 12, 2017
    Assignee: Micron Technology, Inc.
    Inventors: Durai Vishak Nirmal Ramaswamy, Kirk D. Prall
  • Patent number: 9761580
    Abstract: A method of forming an array comprising pairs of vertically opposed capacitors comprises forming an upwardly-open conductive lining in individual capacitor openings in insulative-comprising material. An elevational mid-portion of individual of the conductive linings is removed to form an upper capacitor electrode lining and a lower capacitor electrode lining that are elevationally separate and spaced from one another in the individual capacitor openings. A capacitor insulator is formed radially inward of the upper and lower capacitor electrode linings in the individual capacitor openings. Conductive material is formed radially inward of the capacitor insulator in the individual capacitor openings and elevationally between the capacitor electrode linings. The conductive material is formed to comprise a shared capacitor electrode that is shared by vertically opposed capacitors in individual of the pairs of vertically opposed capacitors. Additional methods and structure independent of method are disclosed.
    Type: Grant
    Filed: November 1, 2016
    Date of Patent: September 12, 2017
    Assignee: Micron Technology, Inc.
    Inventor: Durai Vishak Nirmal Ramaswamy
  • Publication number: 20170236828
    Abstract: A memory cell includes a select device and a capacitor electrically coupled in series with the select device. The capacitor includes two conductive capacitor electrodes having ferroelectric material there-between. The capacitor has an intrinsic current leakage path from one of the capacitor electrodes to the other through the ferroelectric material. There is a parallel current leakage path from the one capacitor electrode to the other. The parallel current leakage path is circuit-parallel the intrinsic path and of lower total resistance than the intrinsic path. Other aspects are disclosed.
    Type: Application
    Filed: May 2, 2017
    Publication date: August 17, 2017
    Inventors: Kamal M. Karda, Qian Tao, Durai Vishak Nirmal Ramaswamy, Haitao Liu, Kirk D. Prall, Ashonita A. Chavan
  • Patent number: 9721639
    Abstract: Methods, systems, and devices for operating a ferroelectric memory cell or cells are described. A cell may be written with a value that is intended to convey a different logic state than may typically be associated with the value. For example, a cell that has stored a charge associated with one logic state for a time period may be re-written to store a different charge, and the re-written cell may still be read to have the originally stored logic state. An indicator may be stored in a latch to indicate whether the logic state currently stored by the cell is the intended logic state of the cell. A cell may, for example, be re-written with an opposite value periodically, based on the occurrence of an event, or based on a determination that the cell has stored one value (or charge) for a certain time period.
    Type: Grant
    Filed: June 21, 2016
    Date of Patent: August 1, 2017
    Assignee: MICRON TECHNOLOGY, INC.
    Inventors: Alessandro Calderoni, Durai Vishak Nirmal Ramaswamy, Kirk Prall, Ferdinando Bedeschi
  • Publication number: 20170162587
    Abstract: A method used in forming an electronic component comprising conductive material and ferroelectric material comprises forming a non-ferroelectric metal oxide-comprising insulator material over a substrate. A composite stack comprising at least two different composition non-ferroelectric metal oxides is formed over the substrate. The composite stack has an overall conductivity of at least 1×102 Siemens/cm. The composite stack is used to render the non-ferroelectric metal oxide-comprising insulator material to be ferroelectric. Conductive material is formed over the composite stack and the insulator material. Ferroelectric capacitors and ferroelectric field effect transistors independent of method of manufacture are also disclosed.
    Type: Application
    Filed: December 3, 2015
    Publication date: June 8, 2017
    Inventors: Ashonita A. Chavan, Durai Vishak Nirmal Ramaswamy, Manuj Nahar
  • Patent number: 9673203
    Abstract: A memory cell includes a select device and a capacitor electrically coupled in series with the select device. The capacitor includes two conductive capacitor electrodes having ferroelectric material there-between. The capacitor has an intrinsic current leakage path from one of the capacitor electrodes to the other through the ferroelectric material. There is a parallel current leakage path from the one capacitor electrode to the other. The parallel current leakage path is circuit-parallel the intrinsic path and of lower total resistance than the intrinsic path. Other aspects are disclosed.
    Type: Grant
    Filed: March 9, 2016
    Date of Patent: June 6, 2017
    Assignee: Micron Technology, Inc.
    Inventors: Kamal M. Karda, Qian Tao, Durai Vishak Nirmal Ramaswamy, Haitao Liu, Kirk D. Prall, Ashonita A. Chavan
  • Publication number: 20170154999
    Abstract: Some embodiments include transistor constructions having a first insulative structure lining a recess within a base. A first conductive structure lines an interior of the first insulative structure, and a ferroelectric structure lines an interior of the first conductive structure. A second conductive structure is within a lower region of the ferroelectric structure, and the second conductive structure has an uppermost surface beneath an uppermost surface of the first conductive structure. A second insulative structure is over the second conductive structure and within the ferroelectric structure. A pair of source/drain regions are adjacent an upper region of the first insulative structure and are on opposing sides of the first insulative structure from one another.
    Type: Application
    Filed: February 13, 2017
    Publication date: June 1, 2017
    Inventor: Durai Vishak Nirmal Ramaswamy