Patents by Inventor Yuankai Zheng

Yuankai Zheng 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: 11170806
    Abstract: The present disclosure generally relates to a Wheatstone bridge array that has four resistors. Each resistor includes a plurality of TMR films. Each resistor has identical TMR films. The TMR films of two resistors have reference layers that have an antiparallel magnetic orientation relative to the TMR films of the other two resistors. To ensure the antiparallel magnetic orientation, the TMR films are all formed simultaneously and annealed in a magnetic field simultaneously. Thereafter, the TMR films of two resistors are annealed a second time in a magnetic field while the TMR films of the other two resistors are not annealed a second time.
    Type: Grant
    Filed: May 20, 2020
    Date of Patent: November 9, 2021
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Yuankai Zheng, Ming Mao, Daniele Mauri, Chih-Ching Hu, Chen-Jung Chien
  • Patent number: 11169227
    Abstract: The present disclosure generally relates to a Wheatstone bridge that includes a plurality of resistors comprising dual free layer (DFL) TMR structures. The DFL TMR structures include one or more hard bias structures on the side of DLF. Additionally, one or more soft bias structures may also be present on a side of the DFL. Two resistors will have identical hard bias material while two other resistors will have hard bias material that is identical to each other, yet different when compared to the first two resistors. The hard bias materials will provide opposite magnetizations that will provide opposite bias fields that result in two different magnetoresistance responses for the DFL TMR.
    Type: Grant
    Filed: December 30, 2019
    Date of Patent: November 9, 2021
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Chih-Ching Hu, Yung-Hung Wang, Yuankai Zheng, Chen-jung Chien, Ming Mao, Daniele Mauri, Ming Jiang
  • Patent number: 11169228
    Abstract: The present disclosure generally relates to a Wheatstone bridge that has four resistors. Each resistor includes a plurality of tunneling magnetoresistance (TMR) structures. Two resistors have identical TMR structures. The remaining two resistors also have identical TMR structures, though the TMR structures are different from the other two resistors. Additionally, the two resistors that have identical TMR structures each have an additional non-TMR resistor as compared to the remaining two resistors that have identical TMR structures. Therefore, the working bias field for the Wheatstone bridge is non-zero.
    Type: Grant
    Filed: December 30, 2019
    Date of Patent: November 9, 2021
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Yung-Hung Wang, Daniele Mauri, Ming Mao, Chen-jung Chien, Yuankai Zheng, Chih-Ching Hu, Carlos Corona, Matthew Stevenson, Ming Jiang
  • Patent number: 11171605
    Abstract: A spin torque oscillator includes a first electrode, a second electrode and a device layer stack located between the first electrode and the second electrode. The device layer stack includes a spin polarization layer including a first ferromagnetic material, an assist layer including a third ferromagnetic material, a ferromagnetic oscillation layer including a second ferromagnetic material located between the spin polarization layer and the assist layer, a nonmagnetic spacer layer located between the spin polarization layer and the ferromagnetic oscillation, and a nonmagnetic coupling layer located between the ferromagnetic oscillation layer and the assist layer. The assist layer is antiferromagnetically coupled to the ferromagnetic oscillation layer through the non-magnetic coupling layer, and the assist layer has a magnetization that is coupled to a magnetization of the ferromagnetic oscillation layer.
    Type: Grant
    Filed: May 29, 2020
    Date of Patent: November 9, 2021
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Yuankai Zheng, Zheng Gao, Susumu Okamura, James Freitag
  • Patent number: 11125840
    Abstract: The present disclosure generally relates to a tunnel magnetoresistive (TMR) device. The TMR device includes a high radiation reflective layer between the bottom shield of the TMR device and the magnetic seed layer. The high radiation reflective layer helps to maintain the TMR device temperature during transportation between processing chambers. Additionally, the high radiation reflective layer decreases the resistance area (RA) of the TMR device while also increasing the magnetoresistance (MR) of the TMR device.
    Type: Grant
    Filed: February 18, 2020
    Date of Patent: September 21, 2021
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Yuankai Zheng, Christian Kaiser, Zhitao Diao
  • Publication number: 20210255256
    Abstract: The present disclosure generally relates to a tunnel magnetoresistive (TMR) device. The TMR device includes a high radiation reflective layer between the bottom shield of the TMR device and the magnetic seed layer. The high radiation reflective layer helps to maintain the TMR device temperature during transportation between processing chambers. Additionally, the high radiation reflective layer decreases the resistance area (RA) of the TMR device while also increasing the magnetoresistance (MR) of the TMR device.
    Type: Application
    Filed: February 18, 2020
    Publication date: August 19, 2021
    Inventors: Yuankai ZHENG, Christian KAISER, Zhitao DIAO
  • Publication number: 20210201943
    Abstract: The present disclosure generally relates to a Wheatstone bridge array that has four resistors. Each resistor includes a plurality of TMR films. Each resistor has identical TMR films. The TMR films of two resistors have reference layers that have an antiparallel magnetic orientation relative to the TMR films of the other two resistors. To ensure the antiparallel magnetic orientation, the TMR films are all formed simultaneously and annealed in a magnetic field simultaneously. Thereafter, the TMR films of two resistors are annealed a second time in a magnetic field while the TMR films of the other two resistors are not annealed a second time.
    Type: Application
    Filed: May 20, 2020
    Publication date: July 1, 2021
    Inventors: Yuankai ZHENG, Ming MAO, Daniele MAURI, Chih-Ching HU, Chen-Jung CHIEN
  • Publication number: 20210063507
    Abstract: The present disclosure generally relates to a Wheatstone bridge array that has four resistors. Each resistor includes a plurality of TMR structures. Two resistors have identical TMR structures. The remaining two resistors also have identical TMR structures, though the TMR structures are different from the other two resistors. Additionally, the two resistors that have identical TMR structures have a different resistance area as compared to the remaining two resistors that have identical TMR structures. Therefore, the working bias field for the Wheatstone bridge array is non-zero.
    Type: Application
    Filed: December 30, 2019
    Publication date: March 4, 2021
    Inventors: Yuankai ZHENG, Christian KAISER, Zhitao DIAO, Chih-Ching HU, Chen-jung CHIEN, Yung-Hung WANG, Dujiang WAN, Ronghui ZHOU, Ming MAO, Ming JIANG, Daniele MAURI
  • Publication number: 20210063505
    Abstract: A method of fabricating a TMR based magnetic sensor in a Wheatstone configuration includes conducting a first anneal of a magnetic tunnel junction (MTJ) and conducting a second anneal of the MTJ. The MTJ includes a first antiferromagnetic (AFM) pinning layer, a pinned layer over the first AFM pinning layer, an anti-parallel coupled layer over the pinned layer, a reference layer over the anti-parallel coupled layer, a barrier layer over the reference layer, a free layer over the barrier layer, and a second antiferromagnetic pinning layer over the free layer. The first anneal of the MTJ sets the first AFM pinning layer, the pinned layer, the free layer, and the second AFM pinning layer in a first magnetization direction. The second anneal of the MTJ resets the free layer and the second AFM pinning layer in a second magnetization direction. An operating field range of the TMR based magnetic sensor is over ±100 Oe.
    Type: Application
    Filed: December 27, 2019
    Publication date: March 4, 2021
    Inventors: Daniele MAURI, Yuankai ZHENG, Lei WANG, Christian KAISER
  • Publication number: 20210063502
    Abstract: A tunneling magnetoresistance (TMR) sensor device is disclosed that includes four or more TMR resistors. The TMR sensor device comprises a first TMR resistor comprising a first TMR film, a second TMR resistor comprising a second TMR film different than the first TMR film, a third TMR resistor comprising the second TMR film, and a fourth TMR resistor comprising the first TMR film. The first, second, third, and fourth TMR resistors are disposed in the same plane. The first TMR film comprises a synthetic anti-ferromagnetic pinned layer having a magnetization direction of the reference layer orthogonal to a free layer. The second TMR film comprises a double synthetic anti-ferromagnetic pinned layer having a magnetization direction of the reference layer orthogonal to the magnetization of a free layer, but opposite to the magnetization direction of the reference layer of the first TMR film.
    Type: Application
    Filed: December 18, 2019
    Publication date: March 4, 2021
    Inventors: Chih-Ching HU, Yung-Hung WANG, Ann Lorraine CARVAJAL, Ming MAO, Chen-Jung CHIEN, Yuankai ZHENG, Ronghui ZHOU, Dujiang WAN, Carlos CORONA, Daniele MAURI, Ming JIANG
  • Publication number: 20210063508
    Abstract: The present disclosure generally relates to a Wheatstone bridge that includes a plurality of resistors comprising dual free layer (DFL) TMR structures. The DFL TMR structures include one or more hard bias structures on the side of DLF. Additionally, one or more soft bias structures may also be present on a side of the DFL. Two resistors will have identical hard bias material while two other resistors will have hard bias material that is identical to each other, yet different when compared to the first two resistors. The hard bias materials will provide opposite magnetizations that will provide opposite bias fields that result in two different magnetoresistance responses for the DFL TMR.
    Type: Application
    Filed: December 30, 2019
    Publication date: March 4, 2021
    Inventors: Chih-Ching HU, Yung-Hung WANG, Yuankai ZHENG, Chen-jung CHIEN, Ming MAO, Daniele MAURI, Ming JIANG
  • Publication number: 20210063500
    Abstract: Embodiments of the present disclosure generally relate to a large field range TMR sensor of magnetic tunnel junctions (MTJs) with a free layer having an intrinsic anisotropy. In one embodiment, a tunnel magnetoresistive (TMR) based magnetic sensor in a Wheatstone configuration includes at least one MTJ. The MTJ includes a free layer having an intrinsic anisotropy produced by deposition at a high oblique angle from normal. Magnetic domain formations within the free layer can be further controlled by a pinned layer canted at an angle to the intrinsic anisotropy of the free layer, by a hard bias element, by shape anisotropy, or combinations thereof.
    Type: Application
    Filed: December 27, 2019
    Publication date: March 4, 2021
    Inventors: Daniele MAURI, Alexander M. ZELTSER, Goncalo BAIAO DE ALBUQUERQUE, Yuankai ZHENG, Christian KAISER
  • Publication number: 20210063504
    Abstract: A tunneling magnetoresistance (TMR) sensor device is disclosed that includes one or more TMR sensors. The TMR sensor device comprises a first resistor comprising a first TMR film, a second resistor comprising a second TMR film different than the first TMR film, a third resistor comprising the second TMR film, and a fourth resistor comprising the first TMR film. The first TMR film comprises a reference layer having a first magnetization direction anti-parallel to a second magnetization direction of a pinned layer. The second TMR film comprises a reference layer having a first magnetization direction parallel to a second magnetization direction of a first pinned layer, and a second pinned layer having a third magnetization direction anti-parallel to the first magnetization direction of the reference layer and the second magnetization direction of the first pinned layer.
    Type: Application
    Filed: December 18, 2019
    Publication date: March 4, 2021
    Inventors: Yuankai ZHENG, Christian KAISER, Zhitao DIAO, Chih-Ching HU, Chen-Jung CHIEN, Yung-Hung WANG, Dujiang WAN, Ronghui ZHOU, Ming MAO, Ming JIANG, Daniele MAURI
  • Publication number: 20210063509
    Abstract: The present disclosure generally relates to a Wheatstone bridge that has four resistors. Each resistor includes a plurality of TMR structures. Two resistors have identical TMR structures. The remaining two resistors also have identical TMR structures, though the TMR structures are different from the other two resistors. Additionally, the two resistors that have identical TMR structures each have an additional non-TMR resistor as compared to the remaining two resistors that have identical TMR structures. Therefore, the working bias field for the Wheatstone bridge is non-zero.
    Type: Application
    Filed: December 30, 2019
    Publication date: March 4, 2021
    Inventors: Yung-Hung WANG, Daniele MAURI, Ming MAO, Chen-jung CHIEN, Yuankai ZHENG, Chih-Ching HU, Carlos CORONA, Matthew STEVENSON, Ming JIANG
  • Publication number: 20210055361
    Abstract: The present disclosure generally relates to a Wheatstone bridge array comprising TMR sensors and a method of fabrication thereof. In the Wheatstone bridge array, there are four distinct TMR sensors. The TMR sensors are all fabricated simultaneously to create four identical TMR sensors that have synthetic antiferromagnetic free layers as the top layer. The synthetic antiferromagnetic free layers comprise a first magnetic layer, a spacer layer, and a second magnetic layer. After forming the four identical TMR sensors, the spacer layer and the second magnetic layer are removed from two TMR sensors. Following the removal of the spacer layer and the second magnetic layer, a new magnetic layer is formed on the now exposed first magnetic layer such that the new magnetic layer has substantially the same thickness as the spacer layer and second magnetic layer combined.
    Type: Application
    Filed: December 30, 2019
    Publication date: February 25, 2021
    Inventors: Yuankai ZHENG, Christian KAISER, Zhitao DIAO, Chih-Ching HU, Chen-jung CHIEN, Yung-Hung WANG, Ming MAO, Ming JIANG
  • Publication number: 20210057638
    Abstract: A Wheatstone bridge array comprising a tunneling magnetoresistive (TMR) sensor and a method for manufacturing is disclosed. The bottom lead for the TMR sensor has a very small surface roughness due to not only chemical mechanical planarization (CMP) but also due to forming the bottom lead from multiple layers. The multiple layers include at least a bottom first metal layer and a top second metal layer disposed on the first metal layer. The second metal layer generally has a lower surface roughness than the first metal layer. Additionally, the second metal layer has a slower polishing rate. Therefore, not only does the second metal layer reduce the surface roughness simply be being present, but the slower polishing rate enables the top second metal film to be polished to a very fine surface roughness of less than or equal to ˜2 Angstroms.
    Type: Application
    Filed: December 30, 2019
    Publication date: February 25, 2021
    Inventors: Ronghui ZHOU, Ming MAO, Ming JIANG, Yuankai ZHENG, Chen-jung CHIEN, Yung-Hung WANG, Chih-Ching HU
  • Publication number: 20210055360
    Abstract: Embodiments of the present disclosure generally relate to a sensor of magnetic tunnel junctions (MTJs) with shape anisotropy. In one embodiment, a tunnel magnetoresistive (TMR) based magnetic sensor in a Wheatstone configuration includes at least one magnetic tunnel junctions (MTJ). The MTJ includes a free layer having a first edge and a second edge. The free layer has a thickness of about 100 ? or more. The free layer has a width and a height with a width-to-height aspect ratio of about 4:1 or more. The MTJ has a first hard bias element positioned proximate the first edge of the free layer and a second hard bias element positioned proximate the second edge of the free layer.
    Type: Application
    Filed: December 27, 2019
    Publication date: February 25, 2021
    Inventors: Daniele MAURI, Lei WANG, Yuankai ZHENG, Christian KAISER, Chih-Ching HU, Ming MAO, Ming JIANG, Petrus Antonius VAN DER HEIJDEN
  • Publication number: 20200286508
    Abstract: A read head includes a first ferromagnetic layer, a second ferromagnetic layer, a first diffusion-assist nonmagnetic metallic layer located between the first ferromagnetic layer and the second ferromagnetic layer, a second diffusion-assist nonmagnetic metallic layer located between the first ferromagnetic layer and the second ferromagnetic layer, and a semiconductor spacer layer located between the first diffusion-assist nonmagnetic metallic layer and the second diffusion-assist nonmagnetic metallic layer.
    Type: Application
    Filed: March 5, 2019
    Publication date: September 10, 2020
    Inventors: Yuankai ZHENG, Christian KAISER, Zhitao DIAO
  • Patent number: 10755733
    Abstract: A read head includes a first ferromagnetic layer, a second ferromagnetic layer, a first diffusion-assist nonmagnetic metallic layer located between the first ferromagnetic layer and the second ferromagnetic layer, a second diffusion-assist nonmagnetic metallic layer located between the first ferromagnetic layer and the second ferromagnetic layer, and a semiconductor spacer layer located between the first diffusion-assist nonmagnetic metallic layer and the second diffusion-assist nonmagnetic metallic layer.
    Type: Grant
    Filed: March 5, 2019
    Date of Patent: August 25, 2020
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Yuankai Zheng, Christian Kaiser, Zhitao Diao
  • Patent number: 10249329
    Abstract: A current perpendicular-to-the-plane magnetoresistive (CPP-MR) sensor for a magnetic recording medium has a substantially wedge-shaped free ferromagnetic layer. The free layer thickness is tapered from the back edge (the edge recessed from the medium-facing surface) to the front edge at the medium-facing surface. The thinner free layer front edge thickness reduces the read gap (the spacing between the two sensor magnetic shields), which improves the resolution of the sensor, which in turn allows the bits to be placed closer together in the along-the-track direction. The free layer is thicker at the back edge so the volume of free layer ferromagnetic material can be maintained at the level required for high amplitude of the readback signal.
    Type: Grant
    Filed: November 21, 2017
    Date of Patent: April 2, 2019
    Assignee: Western Digital Technologies, Inc.
    Inventors: Chih-Ching Hu, Yuankai Zheng, Yung-Hung Wang