Patents by Inventor Lien-Chang Wang

Lien-Chang Wang 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: 7430135
    Abstract: Magnetic multilayer structures, such as magnetic or magnetoresistive tunnel junctions (MTJs) and spin valves, having one or more spin diffusion layers to diffuse the electron spins outside the MTJ or spin valve structure to reduce the spin transfer switching current for switching the free layer.
    Type: Grant
    Filed: December 23, 2005
    Date of Patent: September 30, 2008
    Assignee: Grandis Inc.
    Inventors: Yiming Huai, Zhitao Diao, Alex Panchula, Eugene Youjun Chen, Lien-Chang Wang
  • Patent number: 7420837
    Abstract: A method for writing a memory cell of a magnetoresistive random access memory (MRAM) device includes, sequentially, providing a first magnetic field in a first direction, providing a second magnetic field in a second direction substantially perpendicular to the first direction, turning off the first magnetic field, providing a third magnetic field in a third direction opposite to the first direction, turning off the second magnetic field, and turning off the third magnetic field. A method for switching magnetic moments in an MRAM memory cell includes providing a magnetic field in a direction forming a blunt angle with a direction of a bias magnetic field. A method for reading an MRAM device includes partially switching magnetic moments in a reference memory cell to generate a reference current; measuring a read current through a memory cell to be read; and comparing the read current with the reference current.
    Type: Grant
    Filed: January 25, 2006
    Date of Patent: September 2, 2008
    Assignee: Industrial Technology Research Institute
    Inventors: Chien-Chung Hung, Ming-Jer Kao, Yuan-Jen Lee, Lien-Chang Wang
  • Patent number: 7397694
    Abstract: A magnetic memory array. A first bit line provides a first writing magnetic field to a magnetic memory cell. A second bit line provides a second writing magnetic field to a reference magnetic memory cell. A word line provides a third writing magnetic field to the magnetic memory cell and a fourth writing magnetic field to the reference magnetic memory cell. The third writing magnetic field exceeds the fourth writing magnetic field.
    Type: Grant
    Filed: January 26, 2006
    Date of Patent: July 8, 2008
    Assignee: Industrial Technology Research Institute
    Inventors: Chi-Ming Chen, Chien-Chung Hung, Young-Shying Chen, Lien-Chang Wang
  • Publication number: 20080151611
    Abstract: A method and system for providing a magnetic memory is described. The method and system include providing magnetic memory cells, local and global word lines, bit lines, and source lines. Each magnetic memory cell includes a magnetic element and a selection device connected with the magnetic element. The magnetic element is programmed by first and second write currents driven through the magnetic element in first and second directions. The local word lines are connected with the selection device of and have a first resistivity. Each global word line corresponds to a portion of the local word lines and has a resistivity lower than the first resistivity. The bit lines are connected with the magnetic element. The source lines are connected with the selection device. Each source line corresponds to a more than one of the magnetic memory cells and carries the first and second write currents.
    Type: Application
    Filed: February 13, 2008
    Publication date: June 26, 2008
    Applicants: GRANDIS, INC., RENESAS TECHNOLOGY CORP.
    Inventors: Xiao Luo, Eugene Youjun Chen, Lien-Chang Wang, Yiming Huai
  • Patent number: 7379327
    Abstract: A method and system for providing a magnetic memory. The magnetic memory includes magnetic storage cells in an array, bit lines, and source lines. Each magnetic storage cell includes at least one magnetic element. The magnetic element(s) are programmable by write currents driven through the magnetic element(s). Each magnetic element has free and pinned layer(s) and a dominant spacer.
    Type: Grant
    Filed: June 26, 2006
    Date of Patent: May 27, 2008
    Assignees: Grandis, Inc., Renesas Technology Corp.
    Inventors: Eugene Youjun Chen, Yiming Huai, Alex Fischer Panchula, Lien-Chang Wang, Xiao Luo
  • Patent number: 7345912
    Abstract: A method and system for providing a magnetic memory is described. The method and system include providing magnetic memory cells, local and global word lines, bit lines, and source lines. Each magnetic memory cell includes a magnetic element and a selection device connected with the magnetic element. The magnetic element is programmed by first and second write currents driven through the magnetic element in first and second directions. The local word lines are connected with the selection device of and have a first resistivity. Each global word line corresponds to a portion of the local word lines and has a resistivity lower than the first resistivity. The bit lines are connected with the magnetic element. The source lines are connected with the selection device. Each source line corresponds to a more than one of the magnetic memory cells and carries the first and second write currents.
    Type: Grant
    Filed: June 1, 2006
    Date of Patent: March 18, 2008
    Assignees: Grandis, Inc., Renesas Technology Corp.
    Inventors: Xiao Luo, Eugene Youjun Chen, Lien-Chang Wang, Yiming Huai
  • Publication number: 20070297223
    Abstract: A method and system for providing a magnetic memory is described. The magnetic memory includes magnetic storage cells in an array, bit lines, and source lines. Each magnetic storage cell includes at least one magnetic element. The magnetic element(s) are programmable by write currents driven through the magnetic element(s). Each magnetic element has free and pinned layer(s) and a dominant spacer.
    Type: Application
    Filed: June 26, 2006
    Publication date: December 27, 2007
    Inventors: Eugene Youjun Chen, Yiming Huai, Alex Fischer Panchula, Lien-Chang Wang, Xiao Luo
  • Publication number: 20070279968
    Abstract: A method and system for providing a magnetic memory is described. The method and system include providing magnetic memory cells, local and global word lines, bit lines, and source lines. Each magnetic memory cell includes a magnetic element and a selection device connected with the magnetic element. The magnetic element is programmed by first and second write currents driven through the magnetic element in first and second directions. The local word lines are connected with the selection device of and have a first resistivity. Each global word line corresponds to a portion of the local word lines and has a resistivity lower than the first resistivity. The bit lines are connected with the magnetic element. The source lines are connected with the selection device. Each source line corresponds to a more than one of the magnetic memory cells and carries the first and second write currents.
    Type: Application
    Filed: June 1, 2006
    Publication date: December 6, 2007
    Inventors: Xiao Luo, Eugene Youjun Chen, Lien-Chang Wang, Yiming Huai
  • Publication number: 20070279967
    Abstract: A method and system for providing and using a magnetic storage cell and magnetic memory is described. The method and system include providing a magnetic element and providing a selection device. The magnetic element is programmable to a first state by a first write current driven through the magnetic element in a first direction and to a second state by a second write current driven through the magnetic element in a second direction. The selection device is connected with the magnetic element. The selection device includes a gate having an aperture therein. The selection device is configured such that the first write current and second write current are provided to the magnetic element across the aperture.
    Type: Application
    Filed: May 18, 2006
    Publication date: December 6, 2007
    Inventors: Xiao Luo, Lien-Chang Wang
  • Publication number: 20070246787
    Abstract: Techniques and device designs associated with devices having magnetic or magnetoresistive tunnel junctions (MTJs) configured to operate based on spin torque transfer switching. On-plug MTJ designs and fabrication techniques are described.
    Type: Application
    Filed: March 29, 2006
    Publication date: October 25, 2007
    Inventors: Lien-Chang Wang, Eugene Chen, Yiming Huai, Zhitao Diao
  • Publication number: 20070200188
    Abstract: A magnetic random access memory having reference magnetic resistance is provided. The memory includes at least one magnetic memory cell having an antiferromagnet layer, a pinned layer formed thereon, a tunnel barrier layer formed thereon, and a free layer formed thereon. The pinned layer and free layer are arranged orthogonally to form a reference magnetic resistance state. Through the provided MRAM structure, the access accuracy is greatly increased and the access speed is accelerated.
    Type: Application
    Filed: May 1, 2007
    Publication date: August 30, 2007
    Applicant: INDUSTRIAL TECHNOLOGY RESEARCH INSTITUTE
    Inventors: Chien-Chung Hung, Yung-Hsiang Chen, Ming-Jer Kao, Kuo-Lung Chen, Lien-Chang Wang, Yung-Hung Wang
  • Publication number: 20070171694
    Abstract: Magnetic multilayer structures, such as magnetic or magnetoresistive tunnel junctions (MTJs) and spin valves, having one or more spin diffusion layers to diffuse the electron spins outside the MTJ or spin valve structure to reduce the spin transfer switching current for switching the free layer.
    Type: Application
    Filed: December 23, 2005
    Publication date: July 26, 2007
    Inventors: Yiming Huai, Zhitao Diao, Alex Panchula, Eugene Chen, Lien-Chang Wang
  • Patent number: 7230845
    Abstract: A method and system for providing a magnetic memory device are disclosed. The method and system include providing a magnetic element that includes a data storage layer having at least one easy axis in at least a first direction. The method and system also include providing a hard bias structure surrounding a portion of the magnetic element. The hard bias structure is also configured to provide at least one hard bias field essentially parallel to the at least the first direction or essentially perpendicular to the at least the first direction.
    Type: Grant
    Filed: July 29, 2005
    Date of Patent: June 12, 2007
    Assignee: Grandis, Inc.
    Inventors: Lien-Chang Wang, Yiming Huai
  • Patent number: 7208808
    Abstract: A magnetic random access memory with lower switching field is provided. The memory includes a first antiferromagnetic layer, a pinned layer formed on the first antiferromagnetic layer, a tunnel barrier layer formed on the pinned layer, a ferromagnetic free layer formed on the tunnel barrier layer, and a multi-layered metal layer. The multi-layered metal layer is formed by at least one metal layer, where the direction of the anisotropy axis of the antiferromagnetic layer and the ferromagnetic layer and that of the ferromagnetic free layer are arranged orthogonally. The provided memory has the advantage of lowering the switching field of the ferromagnetic layer, and further lowering the writing current.
    Type: Grant
    Filed: June 23, 2005
    Date of Patent: April 24, 2007
    Assignee: Industrial Technology Research Institute
    Inventors: Yuan-Jen Lee, Yung-Hsiang Chen, Wei-Chuan Chen, Ming-Jer Kao, Lien-Chang Wang
  • Patent number: 7187577
    Abstract: A method and system for providing a magnetic memory is included. The method and system include providing at least one magnetic storage cell and at least one dummy resistor coupled with the at least one magnetic storage cell at least for a write operation of the at least one magnetic storage cell. Each of the at least one magnetic storage cell includes a magnetic element and a selection device coupled with the magnetic element. The magnetic element being programmed by a first write current driven through the magnetic element in a first direction and a second write current driven through the magnetic element in a second direction. The selection device is configured to be coupled between the magnetic element and the at least one dummy resistor.
    Type: Grant
    Filed: November 23, 2005
    Date of Patent: March 6, 2007
    Assignee: Grandis, Inc.
    Inventors: Lien-Chang Wang, Zhitao Diao, Yunfei Ding
  • Publication number: 20070030723
    Abstract: A magnetic memory array. A first bit line provides a first writing magnetic field to a magnetic memory cell. A second bit line provides a second writing magnetic field to a reference magnetic memory cell. A word line provides a third writing magnetic field to the magnetic memory cell and a fourth writing magnetic field to the reference magnetic memory cell. The third writing magnetic field exceeds the fourth writing magnetic field.
    Type: Application
    Filed: January 26, 2006
    Publication date: February 8, 2007
    Inventors: Chi-Ming Chen, Chien-Chung Hung, Young-Shying Chen, Lien-Chang Wang
  • Publication number: 20070030727
    Abstract: A method for writing a memory cell of a magnetoresistive random access memory (MRAM) device includes, sequentially, providing a first magnetic field in a first direction, providing a second magnetic field in a second direction substantially perpendicular to the first direction, turning off the first magnetic field, providing a third magnetic field in a third direction opposite to the first direction, turning off the second magnetic field, and turning off the third magnetic field. A method for switching magnetic moments in an MRAM memory cell includes providing a magnetic field in a direction forming a blunt angle with a direction of a bias magnetic field. A method for reading an MRAM device includes partially switching magnetic moments in a reference memory cell to generate a reference current; measuring a read current through a memory cell to be read; and comparing the read current with the reference current.
    Type: Application
    Filed: January 25, 2006
    Publication date: February 8, 2007
    Inventors: Chien-Chung Hung, Ming-Jer Kao, Yuan-Jen Lee, Lien-Chang Wang
  • Patent number: 7111382
    Abstract: Methods are provided for forming current perpendicular to the plane thin film read heads. In one embodiment, the method comprises the steps of forming a lower sensor lead, forming a lower sensor lead cladding of a low sputter yield material on the lower sensor lead, forming a sensor element on the lower sensor lead cladding, and forming an upper sensor lead coupled to the sensor element. The low sputter yield material helps to reduce redeposition of the lower sensor lead material onto side walls of the sensor element as the sensor element is being formed.
    Type: Grant
    Filed: June 18, 2002
    Date of Patent: September 26, 2006
    Assignee: Western Digital (Fremont), Inc.
    Inventors: Kenneth E. Knapp, Ronald A. Barr, Lien-Chang Wang, Benjamin P. Law, James Spallas
  • Publication number: 20060138509
    Abstract: A magnetic random access memory with lower switching field through indirect exchange coupling. The memory includes a first antiferromagnetic layer, a pinned layer formed on the first antiferromagnetic layer, a tunnel barrier layer formed on the pinned layer, a ferromagnetic free layer formed on the tunnel barrier layer, a metal layer formed on the ferromagnetic free layer, and a second antiferromagnetic layer formed on the metal layer. The anisotropy axis of the second antiferromagnetic layer and the ferromagnetic layer and that of the ferromagnetic free layer are arranged in parallel. The net magnetic moment of the antiferromagnetic layer interface between the second antiferromagnetic layer and the metal layer is close to zero. The memory has the advantages of lowering the switching field of the ferromagnetic layer and lowering the writing current.
    Type: Application
    Filed: June 20, 2005
    Publication date: June 29, 2006
    Inventors: Yuan-Jen Lee, Yung-Hung Wang, Lien-Chang Wang, Ming-Jer Kao
  • Publication number: 20060113619
    Abstract: A magnetic random access memory having reference magnetic resistance is provided. The memory includes at least one magnetic memory cell having an antiferromagnet layer, a pinned layer formed thereon, a tunnel barrier layer formed thereon, and a free layer formed thereon. The pinned layer and free layer are arranged orthogonally to form a reference magnetic resistance state. Through the provided MRAM structure, the access accuracy is greatly increased and the access speed is accelerated.
    Type: Application
    Filed: September 13, 2005
    Publication date: June 1, 2006
    Inventors: Chien-Chung Hung, Yung-Hsiang Chen, Ming-Jer Kao, Kuo-Lung Chen, Lien-Chang Wang, Yung-Hung Wang