Patents by Inventor Guohan Hu

Guohan Hu 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: 20230154513
    Abstract: A memory structure, i.e., magnetoresistive random access memory (MRAM) structure, is provided that includes a seeding area including at least a tunnel barrier seed layer located beneath a chemical templating layer that is wider than the magnetic tunnel junction (MTJ) structure that is located on the chemical templating layer. Redeposited metallic material is located on at least a sidewall of the tunnel barrier seed layer of the seeding area so as to shunt that area of the structure. The memory structure has reduced resistance with minimal tunnel magnetoresistance (TMR) loss penalty.
    Type: Application
    Filed: November 15, 2021
    Publication date: May 18, 2023
    Inventors: Pouya Hashemi, Jonathan Zanhong Sun, Guohan Hu, Saba Zare
  • Patent number: 11557628
    Abstract: A multilayered magnetic free layer structure is provided that includes a first magnetic free layer and a second magnetic free layer separated by a non-magnetic layer in which the first magnetic free layer is composed of an ordered magnetic alloy. The ordered magnetic alloy provides a first magnetic free layer that has low moment, but is strongly magnetic. The use of such an ordered magnetic alloy first magnetic free layer in a multilayered magnetic free layer structure substantially reduces the switching current needed to reorient the magnetization of the two magnetic free layers.
    Type: Grant
    Filed: December 28, 2020
    Date of Patent: January 17, 2023
    Assignee: International Business Machines Corporation
    Inventors: Daniel Worledge, Guohan Hu
  • Patent number: 11527707
    Abstract: A method for forming a memory device that includes providing a free layer of an alloy of cobalt (Co), iron (Fe) and boron (B) overlying a reference layer; and forming metal layer comprising a boron (B) sink composition atop the free layer. Boron (B) may be diffused from the free layer to the metal layer comprising the boron sink composition. At least a portion of the metal layer including the boron (B) sink composition is removed. A metal oxide is formed atop the free layer. The free layer may be a crystalline cobalt and iron alloy. An interface between the metal oxide and free layer can provide perpendicular magnetic anisotropy character.
    Type: Grant
    Filed: November 18, 2019
    Date of Patent: December 13, 2022
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Stephen L. Brown, Guohan Hu, Jonathan Z. Sun, Daniel C. Worledge
  • Patent number: 11501810
    Abstract: A modified double magnetic tunnel junction structure is provided which includes an amorphous spin diffusion layer (i.e., an amorphous non-magnetic, spin-conducting metallic layer) sandwiched between a magnetic free layer and a first tunnel barrier layer; the first tunnel barrier layer contacts a first magnetic reference layer. A second tunnel barrier layer is located on the magnetic free layer and a second magnetic reference layer is located on the second tunnel barrier layer. Such a modified double magnetic tunnel junction structure exhibits efficient switching (at a low current) and speedy readout (high tunnel magnetoresistance).
    Type: Grant
    Filed: March 17, 2021
    Date of Patent: November 15, 2022
    Assignee: International Business Machines Corporation
    Inventors: Daniel Worledge, Guohan Hu
  • Publication number: 20220302368
    Abstract: A modified double magnetic tunnel junction (mDMTJ) structure is provided which includes a narrow base and the use of a spin diffusion layer (i.e., non-magnetic, spin-conducting metallic layer) which gives a low resistance-area product (RA) for the tunnel barrier layer that forms an interface with the spin diffusion layer.
    Type: Application
    Filed: March 17, 2021
    Publication date: September 22, 2022
    Inventors: Daniel Worledge, Guohan Hu
  • Publication number: 20220301612
    Abstract: A modified double magnetic tunnel junction structure is provided which includes an amorphous spin diffusion layer (i.e., an amorphous non-magnetic, spin-conducting metallic layer) sandwiched between a magnetic free layer and a first tunnel barrier layer; the first tunnel barrier layer contacts a first magnetic reference layer. A second tunnel barrier layer is located on the magnetic free layer and a second magnetic reference layer is located on the second tunnel barrier layer. Such a modified double magnetic tunnel junction structure exhibits efficient switching (at a low current) and speedy readout (high tunnel magnetoresistance).
    Type: Application
    Filed: March 17, 2021
    Publication date: September 22, 2022
    Inventors: Daniel Worledge, Guohan Hu
  • Patent number: 11342115
    Abstract: A planar magnetic structure includes a closed loop structure having a plurality of core segments divided into at least two sets. A coil is formed about one or more core segments. A first antiferromagnetic layer is formed on a first set of core segments, and a second antiferromagnetic layer is formed on a second set of core segments. The first and second antiferromagnetic layers include different blocking temperatures and have an easy axis pinning a magnetic moment in two different directions, wherein when current flows through the coil, the magnetic moments rotate to form a closed magnetic loop in the closed loop structure.
    Type: Grant
    Filed: September 4, 2019
    Date of Patent: May 24, 2022
    Assignee: International Business Machines Corporation
    Inventors: Guohan Hu, Naigang Wang
  • Publication number: 20220123049
    Abstract: A multilayered magnetic free layer structure is provided that includes a first magnetic free layer and a second magnetic free layer separated by a non-magnetic layer in which the second magnetic free layer has a lower perpendicular magnetic anisotropy field, Hk, as compared with the first magnetic free layer. The multilayered magnetic free layer structure of the present application substantially reduces the switching current needed to reorient the magnetization of the two magnetic free layers. The lower Hk value of the second magnetic free layer as compared to the first magnetic free layer improves the switching speed of the second magnetic free layer and thus reduces, and even eliminates, write errors.
    Type: Application
    Filed: December 27, 2021
    Publication date: April 21, 2022
    Inventors: Daniel Worledge, Guohan Hu
  • Patent number: 11302863
    Abstract: A bottom pinned magnetic tunnel junction (MTJ) stack having improved switching performance is provided which can be used as a component/element of a spin-transfer torque magnetoresistive random access memory (STT MRAM) device. The improved switching performance which, in turn, can reduce write errors and improve write voltage distributions, is obtained by inserting at least one heavy metal-containing layer into the magnetic free layer and/or by forming a heavy metal-containing layer on a MTJ capping layer that is located above the magnetic free layer.
    Type: Grant
    Filed: February 14, 2020
    Date of Patent: April 12, 2022
    Assignee: International Business Machines Corporation
    Inventors: Guohan Hu, Daniel Worledge
  • Patent number: 11264559
    Abstract: A multilayered magnetic free layer structure is provided that includes a first magnetic free layer and a second magnetic free layer separated by a non-magnetic layer in which the second magnetic free layer is composed of a M1/M2 superlattice structure or a M1/M2 multilayer structure, wherein M1 is a first magnetic metal selected from the group consisting of cobalt (Co), iron (Fe) and alloys thereof, and M2 is a second magnetic metal selected from the group consisting of platinum (Pt), palladium (Pd), nickel (Ni), rhodium (Rh), iridium (Jr), rhenium (Re) and alloys thereof.
    Type: Grant
    Filed: January 30, 2019
    Date of Patent: March 1, 2022
    Assignee: International Business Machines Corporation
    Inventors: Daniel Worledge, Guohan Hu
  • Patent number: 11223010
    Abstract: Techniques relate to forming a magnetic tunnel junction (MTJ). A synthetic antiferromagnetic reference layer is adjacent to a tunnel barrier layer. The synthetic antiferromagnetic reference layer includes a first magnetic layer, a second magnetic layer, and a reference spacer layer sandwiched between the first magnetic layer and the second magnetic layer. A magnetic free layer is adjacent to the tunnel barrier layer so as to be opposite the synthetic antiferromagnetic reference layer. The synthetic antiferromagnetic reference layer has a thickness of at least one of 3 nanometers (nm), 4 nm, and 3-4 nm.
    Type: Grant
    Filed: May 13, 2019
    Date of Patent: January 11, 2022
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Guohan Hu, Younghyun Kim, Daniel C. Worledge
  • Patent number: 11222746
    Abstract: A planar magnetic structure includes a closed loop structure having a plurality of core segments divided into at least two sets. A coil is formed about one or more core segments. A first antiferromagnetic layer is formed on a first set of core segments, and a second antiferromagnetic layer is formed on a second set of core segments. The first and second antiferromagnetic layers include different blocking temperatures and have an easy axis pinning a magnetic moment in two different directions, wherein when current flows through the coil, the magnetic moments rotate to form a closed magnetic loop in the closed loop structure.
    Type: Grant
    Filed: October 28, 2019
    Date of Patent: January 11, 2022
    Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATION
    Inventors: Guohan Hu, Naigang Wang
  • Publication number: 20210257540
    Abstract: A bottom pinned magnetic tunnel junction (MTJ) stack having improved switching performance is provided which can be used as a component/element of a spin-transfer torque magnetoresistive random access memory (STT MRAM) device. The improved switching performance which, in turn, can reduce write errors and improve write voltage distributions, is obtained by inserting at least one heavy metal-containing layer into the magnetic free layer and/or by forming a heavy metal-containing layer on a MTJ capping layer that is located above the magnetic free layer.
    Type: Application
    Filed: February 14, 2020
    Publication date: August 19, 2021
    Inventors: Guohan Hu, Daniel Worledge
  • Publication number: 20210118949
    Abstract: A multilayered magnetic free layer structure is provided that includes a first magnetic free layer and a second magnetic free layer separated by a non-magnetic layer in which the first magnetic free layer is composed of an ordered magnetic alloy. The ordered magnetic alloy provides a first magnetic free layer that has low moment, but is strongly magnetic. The use of such an ordered magnetic alloy first magnetic free layer in a multilayered magnetic free layer structure substantially reduces the switching current needed to reorient the magnetization of the two magnetic free layers.
    Type: Application
    Filed: December 28, 2020
    Publication date: April 22, 2021
    Inventors: Daniel Worledge, Guohan Hu
  • Patent number: 10916581
    Abstract: A multilayered magnetic free layer structure is provided that includes a first magnetic free layer and a second magnetic free layer separated by a non-magnetic layer in which the first magnetic free layer is composed of an ordered magnetic alloy. The ordered magnetic alloy provides a first magnetic free layer that has low moment, but is strongly magnetic. The use of such an ordered magnetic alloy first magnetic free layer in a multilayered magnetic free layer structure substantially reduces the switching current needed to reorient the magnetization of the two magnetic free layers.
    Type: Grant
    Filed: February 4, 2019
    Date of Patent: February 9, 2021
    Assignee: International Business Machines Corporation
    Inventors: Daniel Worledge, Guohan Hu
  • Patent number: 10833253
    Abstract: A magnetoresistive random access memory device (MRAM) device is described. The MRAM device has a stack arrangement in which a tunnel barrier layer is formed over a magnetizable reference layer, a metal layer is formed over the tunnel barrier layer, a free layer of a magnetizable material is formed over the metal layer, and an oxide layer is formed over the free layer as a cap layer. The resulting MRAM device has a thin free layer that exhibits a low magnetic moment.
    Type: Grant
    Filed: February 5, 2016
    Date of Patent: November 10, 2020
    Assignee: International Business Machines Corporation
    Inventor: Guohan Hu
  • Patent number: 10804458
    Abstract: Memory devices and methods of forming the same include forming a memory stack over a bottom electrode. The memory stack has a free magnetic layer formed on the tunnel barrier layer. A first boron-segregating layer is formed directly on the free magnetic layer. An anneal is performed to cause boron to leave the free magnetic layer at an interface with the first boron-segregating layer. A top electrode is formed over the memory stack.
    Type: Grant
    Filed: January 8, 2019
    Date of Patent: October 13, 2020
    Assignees: INTERNATIONAL BUSINESS MACHINES CORPORATION, SAMSUNG ELECTRONICS, CO., LTD.
    Inventors: Guohan Hu, Younghyun Kim, Chandrasekara Kothandaraman, Jeong-Heon Park
  • Publication number: 20200259071
    Abstract: A magnetoresistive random access memory (MRAM) including spin-transfer torque (STT) MRAM is provided that has enhanced data retention. The enhanced data retention is provided by constructing a MTJ pillar having a temperature-independent Delta, where Delta is Delta=Eb/kt, wherein Eb is the activation energy, k is the Boltzmann's constant, and T is the absolute temperature. Notably, the present application provides a way for EB to actually increase with temperature, which can cancel the effect of the term kT, resulting in a temperature independent Delta.
    Type: Application
    Filed: February 8, 2019
    Publication date: August 13, 2020
    Inventors: Daniel Worledge, Guohan Hu
  • Publication number: 20200251525
    Abstract: A multilayered magnetic free layer structure is provided that includes a first magnetic free layer and a second magnetic free layer separated by a non-magnetic layer in which the first magnetic free layer is composed of an ordered magnetic alloy. The ordered magnetic alloy provides a first magnetic free layer that has low moment, but is strongly magnetic. The use of such an ordered magnetic alloy first magnetic free layer in a multilayered magnetic free layer structure substantially reduces the switching current needed to reorient the magnetization of the two magnetic free layers.
    Type: Application
    Filed: February 4, 2019
    Publication date: August 6, 2020
    Inventors: Daniel Worledge, Guohan Hu
  • Publication number: 20200243749
    Abstract: A multilayered magnetic free layer structure is provided that includes a first magnetic free layer and a second magnetic free layer separated by a non-magnetic layer in which the second magnetic free layer is composed of a M1/M2 superlattice structure or a M1/M2 multilayer structure, wherein M1 is a first magnetic metal selected from the group consisting of cobalt (Co), iron (Fe) and alloys thereof, and M2 is a second magnetic metal selected from the group consisting of platinum (Pt), palladium (Pd), nickel (Ni), rhodium (Rh), iridium (Jr), rhenium (Re) and alloys thereof.
    Type: Application
    Filed: January 30, 2019
    Publication date: July 30, 2020
    Inventors: Daniel Worledge, Guohan Hu