Patents by Inventor Haiwen Xi

Haiwen Xi 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: 20100195380
    Abstract: A method and apparatus for writing data to a non-volatile memory cell, such as a spin-torque transfer random access memory (STRAM) memory cell. In some embodiments, a selected resistive state is written to a magnetic tunneling structure by applying a succession of indeterminate write pulses thereto until the selected resistive state is verified.
    Type: Application
    Filed: February 3, 2009
    Publication date: August 5, 2010
    Applicant: Seagate Technology LLC
    Inventors: Xiaobin Wang, Yong Lu, Haiwen Xi, Yuankai Zheng, Yiran Chen, Harry Hongyue Liu, Dimitar Dimitrov, Wei Tian, Brian Seungwhan Lee
  • Publication number: 20100197104
    Abstract: Methods for making a programmable metallization memory cell are disclosed.
    Type: Application
    Filed: April 16, 2010
    Publication date: August 5, 2010
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Haiwen Xi, Ming Sun, Dexin Wang, Shuiyuan Huang, Michael Tang, Song S. Xue
  • Patent number: 7760542
    Abstract: Spin torque magnetic memory elements that have a pinned layer, two free layers, and a current-blocking insulating layer proximate to at least one of the free layers. The resistive state (e.g., low resistance or high resistance) of the memory elements is altered by passing electric current through the element in one direction. In other words, to change from a low resistance to a high resistance, the direction of electric current is the same as to change from a high resistance to a low resistance. The elements have a unidirectional write scheme.
    Type: Grant
    Filed: April 21, 2008
    Date of Patent: July 20, 2010
    Assignee: Seagate Technology LLC
    Inventors: Haiwen Xi, Dexin Wang, Dimitar V. Dimitrov, Paul E. Anderson, Song S. Xue
  • Patent number: 7746687
    Abstract: Methods of writing to a multi-bit MRAM memory unit are described. The method includes to self-detected writing to a multi-bit (i.e., multilevel) thermally assisted MRAM. The self-detected writing increases a reading margin between data state levels and decreases reading margin variability due to cell resistance variation.
    Type: Grant
    Filed: September 30, 2008
    Date of Patent: June 29, 2010
    Assignee: Seagate Technology, LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov, Haiwen Xi
  • Publication number: 20100135061
    Abstract: In some embodiments of the invention a non-volatile memory cell is provided with a first electrode, a second electrode, and one or more side layers of a ferroelectric metal oxide and a ferroelectric material layer between the first and second electrodes. The ferroelectric material layer may be provided between, e.g., adjacent, two side layers of a ferroelectric metal oxide or between a single layer of a ferroelectric metal oxide and an electrode. The ferroelectric metal oxide may in some cases include a uniform layered structure such as a bismuth layer-structured ferroelectric material like Bi4Ti3O12. In some embodiments, the ferroelectric material layer is formed at least partially from PbZrxTi1-xO3. A non-volatile memory array including such memory cells is also provided.
    Type: Application
    Filed: December 2, 2008
    Publication date: June 3, 2010
    Inventors: Shaoping Li, Kaizhong Gao, Insik Jin, Song Xue, Haiwen Xi, Zheng Gao, Eileen Yan
  • Publication number: 20100135067
    Abstract: A method and apparatus for stray magnetic field compensation in a non-volatile memory cell, such as a spin-torque transfer random access memory (STRAM). In some embodiments, a first tunneling barrier is coupled to a reference structure that has a perpendicular anisotropy and a first magnetization direction. A recording structure that has a perpendicular anisotropy is coupled to the first tunneling barrier and a nonmagnetic spacer layer. A compensation layer that has a perpendicular anisotropy and a second magnetization direction in substantial opposition to the first magnetization direction is coupled to the nonmagnetic spacer layer. Further, the memory cell is programmable to a selected resistance state with application of a current to the recording structure.
    Type: Application
    Filed: December 2, 2008
    Publication date: June 3, 2010
    Applicant: Seagate Technology LLC
    Inventors: Dimitar V. Dimitrov, Olle Gunnar Heinonen, Dexin Wang, Haiwen Xi
  • Publication number: 20100128520
    Abstract: An apparatus that includes a magnetic structure including a reference layer; and a free layer; an exchange coupling spacer layer; and a stabilizing layer, wherein the exchange coupling spacer layer is between the magnetic structure and the stabilizing layer and exchange couples the free layer of the magnetic structure to the stabilizing layer.
    Type: Application
    Filed: July 13, 2009
    Publication date: May 27, 2010
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov, Dexin Wang, Haiwen Xi, Xiaobin Wang, Wei Tian, Xiaohua Lou
  • Patent number: 7724469
    Abstract: A magnetic writer includes a write element and an oscillation device disposed adjacent to the write element. The first oscillation device includes a first magnetic layer, a second magnetic layer having a magnetization vector including a component perpendicular to a major plane of the first magnetic layer. The first nonmagnetic layer disposed between the first magnetic layer and the second magnetic layer. The first oscillation device generates a high-frequency oscillation field when a current is directed perpendicular to the major plane of the first magnetic layer.
    Type: Grant
    Filed: December 6, 2006
    Date of Patent: May 25, 2010
    Assignee: Seagate Technology LLC
    Inventors: Kaizhong Gao, Haiwen Xi, Yiming Shi, Sining Mao, Patrick J. Ryan, Song S. Xue, Shaoping Li
  • Publication number: 20100123117
    Abstract: A non volatile memory cell that includes a first electrode; a variable resistive layer disposed on the first electrode; a filament growth layer disposed on the variable resistive layer, the filament growth layer including dielectric material and metal atoms; and a second electrode. In other embodiments, a memory array is disclosed that includes a plurality of non volatile memory cells, each non volatile memory cell including a first electrode; a variable resistive layer disposed on the first electrode; a filament growth layer disposed on the variable resistive layer, the filament growth layer including clusters of a first electrically conductive atomic component interspersed in an oxidized second atomic component; and a second electrode; at least one word line; and at least one bit line, wherein the word line is orthogonal to the bit line and each of the plurality of non volatile memory cells are operatively coupled to a word line and a bit line.
    Type: Application
    Filed: November 19, 2008
    Publication date: May 20, 2010
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Ming Sun, Xilin Peng, Haiwen Xi, Michael Xuefei Tang
  • Publication number: 20100118579
    Abstract: Various embodiments are directed to an apparatus comprising a semiconductor memory array with non-volatile memory unit cells arranged into a NAND block. Each of the unit cells comprises a resistive sense element connected in parallel with a switching element. The resistive sense elements are connected in series to form a first serial path, and the switching elements are connected in series to form a second serial path parallel to the first serial path. Each resistive sense element is serially connected to an adjacent resistive sense element in the block by a tortuous conductive path having a portion that extends substantially vertically between said elements to provide operational isolation therefor.
    Type: Application
    Filed: November 12, 2008
    Publication date: May 13, 2010
    Applicant: Seagate Technology LLC
    Inventors: Harry Hongyue Liu, Haiwen Xi, Antoine Khoueir, Song Xue
  • Publication number: 20100110758
    Abstract: A resistive random access memory (RRAM) cell that includes a first electrode having a lower portion, a continuous side portion and an upper portion, the lower portion and the continuous side portion having an outer surface and an inner surface; a resistive layer having a lower portion, a continuous side portion and an upper portion, the lower portion and the continuous side portion having an outer surface and an inner surface; and a second electrode having a lower portion, an upper portion and an outer surface; wherein the outer surface of the resistive layer directly contacts the inner surface of the first electrode.
    Type: Application
    Filed: October 31, 2008
    Publication date: May 6, 2010
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Shaoping Li, Inisk Jin, Zheng Gao, Eileen Yan, Kaizhong Gao, Haiwen Xi, Song Xue
  • Publication number: 20100109108
    Abstract: Spin-transfer torque memory includes a composite free magnetic element, a reference magnetic element having a magnetization orientation that is pinned in a reference direction, and an electrically insulating and non-magnetic tunneling barrier layer separating the composite free magnetic element from the magnetic reference element. The free magnetic element includes a hard magnetic layer exchanged coupled to a soft magnetic layer. The composite free magnetic element has a magnetization orientation that can change direction due to spin-torque transfer when a write current passes through the spin-transfer torque memory unit.
    Type: Application
    Filed: March 3, 2009
    Publication date: May 6, 2010
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Yuankai Zheng, Dimitar V. Dimitrov, Dexin Wang, Haiwen Xi, Kaizhong Gao, Olle Heinonen, Wenzhong Zhu
  • Publication number: 20100109660
    Abstract: A random number generator device that utilizes a magnetic tunnel junction. An AC current source is in electrical connection to the magnetic tunnel junction to provide an AC current having an amplitude and a frequency through the free layer of the magnetic tunnel junction, the AC current configured to switch the magnetization orientation of the free layer via thermal magnetization. A read circuit is used to determine the relative orientation of the free layer magnetization in relation to the reference layer magnetization orientation.
    Type: Application
    Filed: March 6, 2009
    Publication date: May 6, 2010
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Xiaobin Wang, Wenzhong Zhu, Henry Huang, Yiran Chen, Haiwen Xi
  • Publication number: 20100109110
    Abstract: Magnetic spin-torque memory cells, often referred to as magnetic tunnel junction cells, which have magnetic anisotropies (i.e., magnetization orientation at zero field and zero current) of the associated ferromagnetic layers aligned perpendicular to the wafer plane, or “out-of-plane”. A memory cell may have a ferromagnetic free layer, a first pinned reference layer and a second pinned reference layer, each having a magnetic anisotropy perpendicular to the substrate. The free layer has a magnetization orientation perpendicular to the substrate that is switchable by spin torque from a first orientation to an opposite second orientation.
    Type: Application
    Filed: March 5, 2009
    Publication date: May 6, 2010
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Dexin Wang, Haiwen Xi, Yuankai Zheng, Dimitar Dimitrov
  • Publication number: 20100109656
    Abstract: A magnetic memory device includes a magnetic tunnel junction having a free magnetic layer having a magnetization orientation that is switchable between a high resistance state magnetization orientation and a low resistance state magnetization orientation and a memristor solid state element electrically coupled to the magnetic tunnel junction. The memristor has a device response that is an integrated voltage versus an integrated current.
    Type: Application
    Filed: February 9, 2009
    Publication date: May 6, 2010
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Xiaobin Wang, Yiran Chen, Alan Wang, Haiwen Xi, Wenzhong Zhu, Hai Li, Hongyue Liu
  • Publication number: 20100103717
    Abstract: Method and apparatus for tuning a variable resistance resistive sense element of an electronic device. In some embodiments, a value indicative of a selected number of consecutive pulses is stored in a memory location and a resistive sense element (RSE) is set to a baseline RSE resistance. A tuning operation is performed by applying the selected number of consecutive pulses to the RSE to tune the baseline RSE resistance to a final adjusted resistance.
    Type: Application
    Filed: July 6, 2009
    Publication date: April 29, 2010
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Brian S. Lee, Haiwen Xi, Patrick J. Ryan, Rod Bowman
  • Publication number: 20100103728
    Abstract: A spin-transfer torque memory apparatus and self-reference read and write assist schemes are described. One method of self-reference reading a spin-transfer torque memory unit includes applying a first read current through a magnetic tunnel junction data cell and forming a first bit line read voltage and storing the first bit line read voltage. A magnetic field is applied through the free magnetic layer the forming a magnetic field modified magnetic tunnel junction data cell, the magnetic field rotates the magnetization orientation of the free magnetic layer without switching a resistance state of the magnetic tunnel junction data cell.
    Type: Application
    Filed: February 17, 2009
    Publication date: April 29, 2010
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Wenzhong Zhu, Yiran Chen, Xiaobin Wang, Zheng Gao, Haiwen Xi, Dimitar V. Dimitrov
  • Publication number: 20100102369
    Abstract: A ferroelectric memory cell that has a magnetoelectric element between a first electrode and a second electrode, the magnetoelectric element comprising a ferromagnetic material layer and a multiferroic material layer with an interface therebetween. The magnetization orientation of the ferromagnetic material layer and the multiferroic material layer may be in-plane or out-of-plane. FeRAM memory devices are also provided.
    Type: Application
    Filed: April 8, 2009
    Publication date: April 29, 2010
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Wei Tian, Haiwen Xi, Yuankai Zheng, Venugopalan Vaithyanathan, Insik Jin
  • Publication number: 20100102406
    Abstract: A magnetic stack having a free layer having a switchable magnetization orientation, a reference layer having a pinned magnetization orientation, and a barrier layer therebetween. The stack includes an annular antiferromagnetic pinning layer electrically isolated from the free layer and in physical contact with the reference layer. In some embodiments, the reference layer is larger than the free layer.
    Type: Application
    Filed: July 13, 2009
    Publication date: April 29, 2010
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Haiwen Xi, Antoine Khoueir, Brian Lee, Pat Ryan, Michael Tang, Insik Jin, Paul E. Anderson
  • Publication number: 20100102289
    Abstract: Nonvolatile resistive memory devices are disclosed. In some embodiments, the memory devices comprise multilayer structures including electrodes, one or more resistive storage layers, and separation layers. The separation layers insulate the resistive storage layers to prevent charge leakage from the storage layers and allow for the use of thin resistive storage layers. In some embodiments, the nonvolatile resistive memory device includes a metallic multilayer comprising two metallic layers about an interlayer. A dopant at an interface of the interlayer and metallic layers can provide a switchable electric field within the multilayer.
    Type: Application
    Filed: October 27, 2009
    Publication date: April 29, 2010
    Applicant: SEAGATE TECHNOLOGY LLC
    Inventors: Dimitar Velikov Dimitrov, Insik Jin, Haiwen Xi