Patents by Inventor Keyu Pi

Keyu Pi 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: 20210234092
    Abstract: A method of forming a MTJ with a tunnel barrier having a high tunneling magnetoresistance ratio, and low resistance x area value is disclosed. The method preserves perpendicular magnetic anisotropy in bottom and top magnetic layers that adjoin bottom and top surfaces of the tunnel barrier. A key feature is a passive oxidation step of a first Mg layer that is deposited on the bottom magnetic layer wherein a maximum oxygen pressure is 10-5 torr. A bottom portion of the first Mg layer remains unoxidized thereby protecting the bottom magnetic layer from substantial oxidation during subsequent oxidation and anneal processes that are employed to complete the fabrication of the tunnel barrier and MTJ. An uppermost Mg layer may be formed as the top layer in the tunnel barrier stack before a top magnetic layer is deposited.
    Type: Application
    Filed: April 14, 2021
    Publication date: July 29, 2021
    Inventors: Huanlong Liu, Jian Zhu, Keyu Pi, Ru-Ying Tong
  • Publication number: 20200127195
    Abstract: A method for etching a magnetic tunneling junction (MTJ) structure is described. A stack of MTJ layers is provided on a bottom electrode in a substrate. The MTJ stack is etched to form a MTJ structure wherein portions of sidewalls of the MTJ structure are damaged by the etching. Thereafter, the substrate is removed from an etching chamber wherein sidewalls of the MTJ structure are oxidized. A physical cleaning of the MTJ structure removes damaged portions and oxidized portions of the MTJ sidewalls. Thereafter, without breaking vacuum, an encapsulation layer is deposited on the MTJ structure and bottom electrode.
    Type: Application
    Filed: December 17, 2019
    Publication date: April 23, 2020
    Inventors: Yu-Jen Wang, Keyu Pi, Ru-Ying Tong
  • Patent number: 10516101
    Abstract: A method for etching a magnetic tunneling junction (MTJ) structure is described. A stack of MTJ layers is provided on a bottom electrode in a substrate. The MTJ stack is etched to form a MTJ structure wherein portions of sidewalls of the MTJ structure are damaged by the etching. Thereafter, the substrate is removed from an etching chamber wherein sidewalls of the MTJ structure are oxidized. A physical cleaning of the MTJ structure removes damaged portions and oxidized portions of the MTJ sidewalls. Thereafter, without breaking vacuum, an encapsulation layer is deposited on the MTJ structure and bottom electrode.
    Type: Grant
    Filed: July 30, 2015
    Date of Patent: December 24, 2019
    Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY, LTD.
    Inventors: Yu-Jen Wang, Keyu Pi, Ru-Ying Tong
  • Publication number: 20170033282
    Abstract: A method for etching a magnetic tunneling junction (MTJ) structure is described. A stack of MTJ layers is provided on a bottom electrode in a substrate. The MTJ stack is etched to form a MTJ structure wherein portions of sidewalls of the MTJ structure are damaged by the etching. Thereafter, the substrate is removed from an etching chamber wherein sidewalls of the MTJ structure are oxidized. A physical cleaning of the MTJ structure removes damaged portions and oxidized portions of the MTJ sidewalls. Thereafter, without breaking vacuum, an encapsulation layer is deposited on the MTJ structure and bottom electrode.
    Type: Application
    Filed: July 30, 2015
    Publication date: February 2, 2017
    Inventors: Yu-Jen Wang, Keyu Pi, Ru-Ying Tong
  • Patent number: 9276201
    Abstract: A method of forming a hybrid oxide capping layer (HOCL) is disclosed and used in a magnetic tunnel junction to enhance thermal stability and perpendicular magnetic anisotropy in an adjoining free layer. The HOCL has a lower interface oxide layer and one or more transition metal oxide layers wherein each of the metal layers selected to form a transition metal oxide has an absolute value of free energy of oxide formation less than that of the metal used to make the interface oxide layer. One or more of the HOCL layers is under oxidized. Oxygen from one or more transition metal oxide layers preferably migrates into the interface oxide layer during annealing to further oxidize the interface oxide. As a result, a less strenuous oxidation step is required to initially oxidize the lower HOCL layer and minimizes oxidative damage to the free layer.
    Type: Grant
    Filed: September 28, 2015
    Date of Patent: March 1, 2016
    Assignee: Headway Technologies, Inc.
    Inventors: Keyu Pi, Yu-Jen Wang, Ru-Ying Tong
  • Publication number: 20160020387
    Abstract: A method of forming a hybrid oxide capping layer (HOCL) is disclosed and used in a magnetic tunnel junction to enhance thermal stability and perpendicular magnetic anisotropy in an adjoining free layer. The HOCL has a lower interface oxide layer and one or more transition metal oxide layers wherein each of the metal layers selected to form a transition metal oxide has an absolute value of free energy of oxide formation less than that of the metal used to make the interface oxide layer. One or more of the HOCL layers is under oxidized. Oxygen from one or more transition metal oxide layers preferably migrates into the interface oxide layer during annealing to further oxidize the interface oxide. As a result, a less strenuous oxidation step is required to initially oxidize the lower HOCL layer and minimizes oxidative damage to the free layer.
    Type: Application
    Filed: September 28, 2015
    Publication date: January 21, 2016
    Inventors: Keyu Pi, Yu-Jen Wang, Ru-Ying Tong
  • Patent number: 9236558
    Abstract: A hybrid oxide capping layer (HOCL) is disclosed and used in a magnetic tunnel junction to enhance thermal stability and perpendicular magnetic anisotropy in an adjoining reference layer. The HOCL has an interface oxide layer adjoining the reference layer and one or more transition metal oxide layers wherein each of the metal layers selected to form a transition metal oxide has an absolute value of free energy of oxide formation less than that of the metal used to make the interface oxide layer. One or more of the HOCL layers is under oxidized. Oxygen from one or more transition metal oxide layers preferably migrates into the interface oxide layer during an anneal to further oxidize the interface oxide. As a result, a less strenuous oxidation step is required to initially oxidize the lower HOCL layer and minimizes oxidative damage to the reference layer.
    Type: Grant
    Filed: September 1, 2015
    Date of Patent: January 12, 2016
    Assignee: Headway Technologies, Inc.
    Inventors: Keyu Pi, Yu-Jen Wang, Ru-Ying Tong
  • Publication number: 20150372224
    Abstract: A hybrid oxide capping layer (HOCL) is disclosed and used in a magnetic tunnel junction to enhance thermal stability and perpendicular magnetic anisotropy in an adjoining reference layer. The HOCL has an interface oxide layer adjoining the reference layer and one or more transition metal oxide layers wherein each of the metal layers selected to form a transition metal oxide has an absolute value of free energy of oxide formation less than that of the metal used to make the interface oxide layer. One or more of the HOCL layers is under oxidized. Oxygen from one or more transition metal oxide layers preferably migrates into the interface oxide layer during an anneal to further oxidize the interface oxide. As a result, a less strenuous oxidation step is required to initially oxidize the lower HOCL layer and minimizes oxidative damage to the reference layer.
    Type: Application
    Filed: September 1, 2015
    Publication date: December 24, 2015
    Inventors: Keyu Pi, Yu-Jen Wang, Ru-Ying Tong
  • Publication number: 20150333254
    Abstract: A method of forming a MTJ with a tunnel barrier having a high tunneling magnetoresistance ratio, and low resistance x area value is disclosed. The method preserves perpendicular magnetic anisotropy in bottom and top magnetic layers that adjoin bottom and top surfaces of the tunnel barrier. A key feature is a passive oxidation step of a first Mg layer that is deposited on the bottom magnetic layer wherein a maximum oxygen pressure is 10?5 torr. A bottom portion of the first Mg layer remains unoxidized thereby protecting the bottom magnetic layer from substantial oxidation during subsequent oxidation and anneal processes that are employed to complete the fabrication of the tunnel barrier and MTJ. An uppermost Mg layer may be formed as the top layer in the tunnel barrier stack before a top magnetic layer is deposited.
    Type: Application
    Filed: May 15, 2014
    Publication date: November 19, 2015
    Applicant: Headway Technologies, Inc.
    Inventors: Huanlong Liu, Jian Zhu, Keyu Pi, Ru-Ying Tong
  • Patent number: 9147833
    Abstract: A hybrid oxide capping layer (HOCL) is disclosed and used in a magnetic tunnel junction to enhance thermal stability and perpendicular magnetic anisotropy in an adjoining free layer. The HOCL has a lower interface oxide layer and one or more transition metal oxide layers wherein each of the metal layers selected to form a transition metal oxide has an absolute value of free energy of oxide formation less than that of the metal used to make the interface oxide layer. One or more of the HOCL layers is under oxidized. Oxygen from one or more transition metal oxide layers preferably migrates into the interface oxide layer during an anneal to further oxidize the interface oxide. As a result, a less strenuous oxidation step is required to initially oxidize the lower HOCL layer and minimizes oxidative damage to the free layer.
    Type: Grant
    Filed: July 5, 2013
    Date of Patent: September 29, 2015
    Assignee: Headway Technologies, Inc.
    Inventors: Keyu Pi, Yu-Jen Wang, Ru-Ying Tong
  • Patent number: 9030783
    Abstract: The embodiments disclosed generally relate to a read device in a magnetic recording head. The read device uses parametric excitation to injection lock the STO to an external AC signal with a frequency that is two times the resonance frequency, or more. The field from the media acting on the STO causes a change in the phase between the STO output and the external locking signal, which can be monitored using a phase detection circuit. The injection locking improves the STO signal to noise ratio and simplifies the detection circuit.
    Type: Grant
    Filed: February 6, 2014
    Date of Patent: May 12, 2015
    Assignee: HGST Netherlands B.V.
    Inventors: Patrick M. Braganca, Samir Y. Garzon, Bruce A. Gurney, Keyu Pi, Rehan A. Zakai, Jian Zhu
  • Publication number: 20150008547
    Abstract: A hybrid oxide capping layer (HOCL) is disclosed and used in a magnetic tunnel junction to enhance thermal stability and perpendicular magnetic anisotropy in an adjoining free layer. The HOCL has a lower interface oxide layer and one or more transition metal oxide layers wherein each of the metal layers selected to form a transition metal oxide has an absolute value of free energy of oxide formation less than that of the metal used to make the interface oxide layer. One or more of the HOCL layers is under oxidized. Oxygen from one or more transition metal oxide layers preferably migrates into the interface oxide layer during an anneal to further oxidize the interface oxide. As a result, a less strenuous oxidation step is required to initially oxidize the lower HOCL layer and minimizes oxidative damage to the free layer.
    Type: Application
    Filed: July 5, 2013
    Publication date: January 8, 2015
    Inventors: Keyu Pi, Yu-Jen Wang, Ru-Ying Tong